Module 3.1 and 3.2

Question 1

dUnicellular / singlecellular organism (amoeba)
-fresh water ponds

Answer 1

-all organisms re constanlty , eschaning materials , with their enviornment .
-e.g , amoeba carries out aerobic respirattion generae atp .
-oxygen , needed for aerobic respiration —> diffuses into he cel through the cell membrane .

Question 2

-scientists call the cell membrane an exchange surface .
-when amoeba carries our respiration , it prouduces the gas co2 .
-this co2 diffuses out of the cel via the cell membrane ,

Answer 2

In microscopic organsisms _ amoeba organism , exhange all the substance it needs directly though the cell memerbane , There is two reasons for this .

Question 3

reason one

Answer 3

-microsocopic organisms , relatively low rate of respiration as ehya rent ery active organsimss .

Question 4

reasons two

Answer 4

relatively large compared to volue of the cell . SA:V ,
-calcukae sa;v ratio using this equation

s:volume ratio = surface area / volume

sa;v=24/8 =3:1 96/64=1.5:1 for example

Question 5

-single cell organsisms have a large sa to volume ratio .

Answer 5

they can transfer all of the chemicals they need across the cell membrane .
-However , large multiceullar orgasims sa;V much less .

Question 6

-some small multicellular organsisms do rely on diffusion across their body e.g flatowrm .

Answer 6

by evolvingg a very flat and thin body size all of the cells in the flat are clsoe to the surfce .
-so diffusion corss hte body urfce is sufficne in a fla surface .

-HOWEVER , LARGE MULTICeullar organsims sa : v can not what .
-So multiceullar organsism evovles two specialsied sytems to compensate .

Question 7

evolving one

Answer 7

-evovled specialised gas exchange sytems –> very large surface area ( lungs in mammals gulls in gish .

Question 8

evovling two

Answer 8

specialsied transport sytem to carry moelcules around their bodlood

Question 9

Mammals have a very low surface to volume ratio .
-mammals are also very active animals , mammals maintain a constant body temp .

Answer 9

-this required , an increased rate of aerobic respiration .
for these reasons , mammals have an extremely high oxygen demand .

Question 10

-mammals , get their oxygen from the air , via their lungs shown , structure of human breathing system .

Answer 10

-humans have two lungs which are found in the thorax chest activity .
-the lungs are protected by the ribs .
-The ribs also plays a role in breathing .
-Along , with the intercostal muscles and diaphragm .

Question 11

stage one of breathing

Answer 11

-when humans breathe though their nose , air passes through the nasal cavity .

-hairs in the nasal cavity traps , dust particles and pathogens .
-the nasal cavity also warms and moistens the air before it enter the lungs .

Question 12

stage two of breathing

Answer 12

-The air , then makes it way down a wide tube called the trachea .
-The air then makes it way down a wide tube calle the trachea .

Question 13

the trachea two key adaptations which you need to learn .

Answer 13

-walls of the trachea contain cartilage which is a firm but flexible material .
-The cartilage prevent the walls of the trachea , for collapsing when we inhale .

Question 14

-this diagram shows a view of the trachea looking down towards the lungs .

Answer 14

-as you can see the trachea is very close to the oesophagus , which is the tube carrying food to the stomach .
-Yu’ll notice that the cartilage in the trachea forms a c shape , rather than forming the complete rings ?

Question 15

Why does it not form complete rings ?

Answer 15

The absence if cartilage in the region near the oesophagus allows the food to pass down the oesophagus easily .

Question 16

What is the second adaptation of the trachea

Answer 16

The walls are lined with ciliated epithelial and goblet cells .
-Showing cells lining the walls of the trachea .

Question 17

What s the role of goblet cells

Answer 17

Goblet cells secrete mucus which traps dust particles and pathogens .
-The ciliated epithelial cells have cilia extending from the cell membrane .
-T

Question 18

What do the cilia do ?

Answer 18

The beating of the cilia moves the mucus to the throat .
-The mucus is then swallowed and the dust and pathogens are digested by the stomach enzymes .

Question 19

Going back to our lungs , we can see trachea divide into two bronchi

Answer 19

two bronchus carries air into one of the lung .
-Just like the trachea , the bronchi contain cartilage ciliated epithelial and goblet cells .

Question 20

What does each bronchus split into ?

Answer 20

Each bronchus splits forming progressively narrower airways called bronchioles .
-The walls of larger bronchioles are supported by cartilage , they also contain smooth muscle .

Question 21

What happens when the smooth muscle reflexes ?

Answer 21

The bronchioles widen allowing more air to pass into the deeper part of the lungs .

Question 23

Deep in the lungs the bronchioles are extremely narrow .
What do these bronchioles lead to ?

Answer 23

Air sacs , called alveoli .
-Alveoli are the sites of gas exchange .
-There are hundreds of millions of alveoli in the lungs . The internal walls of the alveoli are covered with a thin layer of moisture .

Question 24

-Close up of the alveoli , the alveoli is covered with blood capillaries .,
What happens to the oxygen in the air ?

Answer 24

Oxygen in the air of the alveoli dissolves nt he mositure on the inside of the alveoli wall .
-The oxygen then diffuses into the red blood cells where it combines with haemoglobin .
-Carbon dioxide diffuses from the blood into the alvelar spcae .

Question 25

Between the alveoli , are elastic fibres which stretch and recoil during breathing .

Answer 25

As we have seen , the alveoli is where gases diffuse in and out of the blood .

Question 26

What is one way alveoli are adapted to maximise the rate of diffusion .

Answer 26

Hundreds of millions of alveoli , these provide a massive surface area for the diffusion of gases .

Question 27

Check sheet for the close up of alveolus and blood capillaries .

Answer 27

Both he wall of the alveolus and the walls of the capillary are only one cell thick . -This means there is a very short diffusion distance between the air in the alveolia nd red blood cells in the capillary .

Question 28

The narrow diameter of the capillary means that the red blood cells are close tot he capillary wall .

Answer 28

This minimises diffusion distance .

Question 29

The extensive capillary network means that once oxygen diffuses into the blood , what happens ?

Answer 29

It is rapidly carried away from the alveoli -This ensures there is always a steep concentration gradient for oxygen .

Question 30

Co2 also has a steep concentration gradient ,a s more is continually brought to the alveoli int he blood stream .

Answer 30

these concentration gradients are also maintained by breathing , which brings fresh air into the alveoli .

Question 31

This ensures there is always a high concentration of oxygen in the alveolar air .

Answer 31

as well as a low concentration of co2 , this helps to ensure a rapid rate of diffusion of these gases .

Question 32

What is breathing also known as ?

Answer 32

Ventilation . -Ventilation brings fresh air from outside of the body into the alveoli . -THIS , increases the concentration of oxygen in the alveoli air spaces whilst decreasing the concentration of co2 . -The effect of this , is to increase the concentration of these gases thus increasing the rate of reaction .

Question 33

What is the mechanism for ventilation ?

Answer 33

Simplified version of the lungs . -Ventilation involves the action of two sets of muscles .

Question 34

Muscle one involved in ventilation

Answer 34

intercostal muscles - which lie between the ribs and the diaphragm . -Which separates the thorax (chest cavity ) from the abdomen . -The two sets of muscles work together to change the volume of the thorax . -

Question 35

What happens if we change the volume of the thorax ?

Answer 35

By changing the volume of the thorax , this changes the pressure of air in the lungs . -The effect of this , is to draw air into the lungs (inhalation ) . Or to expel air from the lugs (exhalation )

Question 36

There are the two sets of intercostal muscles . What are they ?

Answer 36

These are called the external and internal intercostal muscles as they are involved in regular breathing . focus on external -The internal intercostal muscles are involved in stronger breathing , this is what happens when we inhale / breathe in .

Question 37

Stage one of inhalation

Answer 37

during inhalation ,t he external intercostal muscles contract aka they shorten . -this pulls the ribs upwards and outwards l

Question 38

stage two of inhalaiton

Answer 38

at the same time ,t he diaphragm also contracts which causes it tot flatten . The effect of these is to increase the volume of the thorax and lungs . -This reduces the air pressure in the lungs .

Question 39

stage thee of inhalation

Answer 39

as the air pressure in he lungs is now less than atmosphere pressure , air is drawn into he lungs . -air is moves into the alveoli and the elastic fibres between the alveoli stretch . BECAUSE - inhalation involve muscles constrain , inhalation active process .

Question 42

Stage one of exhalation

Answer 42

during regular breathing , exhalation is essentially process as the muscles relax . -Therefore exhalation does not require a great deal of energy .

Question 43

stage two of exhalation

Answer 43

-during exhalation ,the external intercostal muscles relax and return to their original length .

Question 44

stage three of exhalation

Answer 44

the diaphragm also relaxes returning to its usual dhape . -The effects of this is to reduce there volume of the thorax and lungs . -now air pressure in the lungs is gretaher than atmospehrec pressure . -air ispushed out of the lugns .

Question 45

-The elastic fibres between the alveoli also recoil helping to push out he air

Answer 45

scientists call this elastic retraction .

Question 46

volume of lungs changes when we inhale and exhale

Question 47

lungs are surrounded by a pleural membrane . what do theyd o ?

Answer 47

between these membranes there is plural fluid which acts as a lubricant as the lung volume changes

Question 48

As we have seen . during regular breathing exhalation is mainly a passive process .

Answer 48

This is not the case ,when we exhale strongly , as during this internal intercostal macules contract as we exhale strongly . -this pulls the ribs down and inwards forcing air out of the lungs .

Question 49

At the same time , the external intercostal muscles relax

Answer 49

As the internal intercostal muscles relax which the external interoctysal muscles contract . Scientists descrier this as antagnote .

Question 50

What are bony fish and give examples

Answer 50

They are a large group of fish which have evolved a skeleton made of bone Tuna salmon cod and trout

Question 51

Whag js the significant issue when it comes to gas exhange in fish ?

Answer 51

Bony fish are large and active organisms with a very high oxygen requirement -because of their large size they have a very low surface area to volume ratio . 2. The SCALY surface of bony fish does not allow gasses to pass through

Question 52

How do fish get their oxygen ? But what is problem

Answer 52

From the water , but concentration of oxygen in the water is MUCH LOWER than in air . So for these reasons , bony fish have evolved a specialised gas exchange system . Which extracts MAZOMUM AMOUNT of oxygen from water

Question 53

Bony fish have a flap of tissue on either side , slightly behind their head function ? .

Answer 53

This is called operculum I’m and we have behind this the operculum cavity . INSIDE the operculum cavity , we find gills .

Question 54

S1 gas exchange in fish

Answer 54

Oxygen rich water enters the fish through the mouth

Question 55

S2 gas exchange in fish

Answer 55

Water then passes over the gills , In gills oxygen diffuses from the water into the blood . And carbon dioxide diffuses from the blood into the water . Finally water passes through the operculsr opening .

Question 56

Structure of gills ( go all the way to card 397 to continue then come back to do insects )

Answer 56

gills consists of several bony arches , extending from each gill arch are a large number of gill filaments .

Question 57

Insects can be extremely active organisms so what would there oxygen demand be like ?

Answer 57

They would have a very high oxygen demand , for example , during flight .

Question 58

Key , how have gas exchange systems evolved in insects ?

Answer 58

to provide oxygen directly to cells . -although insects do have a specialised transport system , this transfers nutrients and not oxygen .

Question 59

What are insects covered with ?

Answer 59

A protective exoskeleton made of the polysaccharide chitin . -Gases such as oxygen and carbon dioxide do not easily pass though . -so on the surface of the exoskeleton ,t here are small openings called spircales .

Question 60

What do spiracles do ?

Answer 60

Spiracles allow gases such as oxygen and carbon dioxide to diffuse into the body of the insect .

Question 61

What can spiracles leads to ?

Answer 61

Spircales can lead into a network of tubes called the trachea . (trachea are relatively wide tubes with a diameter of around 1 mm) . -trachea extends down into the body of t he insect . -trachea are relatively wide tubes with a diameter of around 1 mm . -trachea extends down and along the insect's body .

Question 62

what is the trachea reinforced with

Answer 62

spirals of chitin . -the chitin prevents the trachea from collapsing example when an insect moves . -extending from the trachea are very fine tubes called tracheoles .

Question 63

What are the adaptations of tracheoles ?

Answer 63

Tracheoles have a diameter of around 1 micrometre , or less . -In fact they are much narrower than shown in the diagram . -each trachea is a single cell that has extended to form a hollowtube .

Question 64

insects

Answer 64

-a huge number of tracheoles extend down inbetween the cells of the insects body .

Question 64

adaptations 2 of tracheoles

Answer 64

unlike trachea , tracheoles are not supported by chitin . -This is because tracheoles have such a narrow diameter and are extremely close to cells , there is a very short diffusion distance for gases moving between the cells and the tracheoles .

Question 65

adaptation 3 of tracheoles

Answer 65

huge number of tracheoles provide a very large surface area for gas exchange . -this allows insects to maintain a very rapid rate of aerobic respiration ( example flight ) .

Question 66

What are the ends of the trachea filled with ?

Answer 66

They are filled with fluid also known as tracheal fluid . -during intense activity , the cells around the tracheoles undergo anaerobic respiration . -anaerobic respiration which produces lactic acid lowering the water potential of the cells .

Question 67

what does lowering the water potential of cells do to the tracheal fluid ?

Answer 67

causes the water in the tracheal fluid to move into the cell . -this reduces the volume of the tracheal fluid drawing air into the tracheoles . -also shows more tracheole surround avoidable for diffusion of oxygen and carbon dioxide .

Question 68

Is gas exchange active or passive in insects ?

Answer 68

It is essentially a passive process . This is because , oxygen diffuses down its co2 gradient from a high concentration in the external air into the lower concentration .

Question 69

describe co2 diffusion in insects

Answer 69

co2 , diffuses down its conc tracheoles gradient . -with a relatively high concentration in the tracheoles out to the external air . rate of diffusion decreases with distance meaning insects tend to be small .

Question 70

smaller size of insects , reduces distance required for diffusion to take place .

Answer 70

...

Question 71

However , what is one problem that insects have ?

Answer 71

This is loss of water . -The walls of the tracheoles are moist and the ends contain tracheal fluid . -Meaning , water vapour can diffuse out of an insect via the spiracles .

Question 72

However , what is one problem that insects have ? (2)

Answer 72

muscular sphincter . -This means insects can reduce water loss by closing their spiracle (example insects oxygen req)

Question 73

ocr , --> how have some insects evolved to increase rate of gas exchange ?

Answer 73

-If , we look at insects ,w e can see they have three main body segments . Head --> Thorax--> Abdomen -Some insects can also contract muscles to change the volume of the thorax and abdomen .

Question 74

ocr , --> how have some insects evolved to increase rate of gas exchange ? (2)

Answer 74

causing , pressure changes in the trachea pushing air in and out . -this bulk movement is called mass movement .

Question 75

-in some insects , the trachea contain expanding sections called air sacs . -What are the adaptations of the air sacs ?

Answer 75

-changes in the volume of the thorax and the abdomen can squeeze the air sacs , causing air to move from the air sacs into the tracheoles . -insects can also use the oxygen in the air sacs during when the spiracles have been closed for water conservation .

Question 76

Larger organisms , have a much lower surface area to volume ration , so what does this mean ?

Answer 76

The vast majority of cells are a large distance from the surface of organisms . -also , large organsisms , are often , very active , and have a high demand of oxygen for aerobic respirations /

Question 77

so , if larger organisms , cannot rely on diffusion alone for the exchange of material , what else do they rely on ?

Answer 77

-we have already seen , how insects fish and humans have specialised gas exchange systems . -This ensures a very efficent gas exchnage sytem for oxygen and carbondioixde .

Question 78

how have insects adapted to their gas exchange system ?

Answer 78

so that gases diffuse directly .

Question 79

How does diffusion work in fish and humans ?

Answer 79

gases dissolve in blood , which acts as a transport system . -The blood then moves around the circulatory system , transferring the gases between the cells and the gas exchange system .

Question 80

what else does blood transfer , other than oxygen ?

Answer 80

Other essential molecules like glucose and amino acids . -when molecules are carried in a transport medium such as blood through a circulatory system , scientists call this mass transport .

Question 81

circulatory system of fish (1)

Answer 81

deoxygenated blood , is pumped by the heart , through the blood vessels to the gills .

Question 82

circulatory system of fish (2)

Answer 82

In the gills , blood passes though narrow blood vessels called capillaries . -oxygen diffuses from the water into the blood .

Question 83

circulatory system of fish (3)

Answer 83

the oxygenated blood now passes from the gills though the blood vessels to the body tissues .

Question 84

circulatory system of fish (4)

Answer 84

when it reaches the body tissues , the blood again passes though narrow capillaries , where oxygen diffuses from the blood to the cells that needd it .

Question 85

circulatory system of fish (5)

Answer 85

finally , the deoxygenated blood , now returns in blood vessels back to the heart .

Question 86

circulatory system of fish (6)

Answer 86

so blood , only passes though the heart only once . -as it moves around the circulatory system scientists call this a single circulatory system .

Question 87

problem with single circulatory system ?

Answer 87

when the blood passes through two sets of narrow capillaries . -firstly , -firstly , in the gills . and secondly , as it passes into the body tissues when the blood passes though capillaries' , blood flows down and looses pressure . -MEANING --> once ,, the blood passes though the gills , blood is moving relatively slowly . -limiting how rapidly oxygen can be delivered to body cells .

Question 88

circulatory system in mammals (1)

Answer 88

deoxygenated blood is pumped under high pressure from the heart to the lungs .

Question 89

circulatory system in mammals (2)

Answer 89

in the lungs , blood passes though the narrow capillaries and oxygen diffuses from air into the blood.

Question 90

circulatory system in mammals (3)

Answer 90

As the blood , has passed though the capillaries , it is moving slowly with lower pressure .

Question 91

circulatory system in mammals (4)

Answer 91

however , now the oxygenated blood returns back to the heart . Pumping blood at high pressure around the body .

Question 92

circulatory system in mammals (5)

Answer 92

as it passes though the body , blood passes through the capillaries and oxygen diffuses to the body cells .

Question 93

circulatory system in mammals (6(

Answer 93

the low pressure , deoxygenated blood now makes it way back to the heart to be pumped again .

Question 94

so double circualtory system , blood passes though twice

Answer 94

this makes sure the blood makes it ways to the body tissues rapidly and under high pressure . -so a double circulatory system can carry oxygen more efficiently , than a single circulatory system .

Question 95

what is a closed sytem ?

Answer 95

-fish and mammmals , blood is always contained in blood vessels as it travels form the heart . this is a closed ciruclaotry sytem . -in a closed cirulatory sytem , blood can move relatively rapidly , and the amout of blood pumped to differen ooorgans can be controlled by constricting or dialiating blood vessels .

Question 96

What is an open circulatory sytem ?

Answer 96

insects have it , insects do not contain blood . -instead , they contain a fluid called haemolymph . -haemolymph carries nutrients also like sugar's but do not carry oxygens // -haemolymph is pumped out of the insects heart and passes directly into the body cavity called haermoroel . -moelcuels are then transferred , becween the haemolymp and body ells an d hten the haemolymph makes its way back into the heart .

Question 97

what is key about haemolymph

Answer 97

It is not carried in Venule , so it is an example of an open circulatory system . -as the haemolympg is not Carried in vessels and jf moves rapidly around the insect . -Also. (!3 insect is nkg essily change or cannot of how how much is moving to different parts of its body .

Question 98

What do arteries branch to form

Answer 98

They form narrow blood vessels called arterioles. Arteries carry the blood to the capillaries from each organ .

Question 99

How does molecules diffuse in the capillaries

Answer 99

-Morley les diffuse from the body cells back into the blood . -finally . The blood then passes from capillary to blood vessels called Venules and the which carry the blood back k tk the heart .

Question 100

What way does the arteries carry the blood ?

Answer 100

Arteries carry the blood away from the heart to the organs blood on the arteries is under high pressure .

Question 101

What is the pulse ?

Answer 101

When the heart beats , a surge of even higher blood Pressure is pushed down the arteries scientists call this PULSE

Question 102

What way does the heart beat even when the heart beats ?

Answer 102

It moved FORWARD -cross ex goin of w typical artery - although I should point out , that very large artistes can have a wide diameter

Question 103

Adaptation of arteries

Answer 103

The first thing to notice is that the artery wall is relatively thick . -l this alllsws the artery to withstand high pressure of the blood .

Question 104

The walls of the artery consist of several layers

Answer 104

…

Question 105

The outer layer of the artery EXPLAIN

Answer 105

The other layer of the artery is rich in the fibrous protein collagen . -collagen plays a structural role in, strengthening the artery wall against the pressure of the blood .

Question 106

Next , the artery has a layer containing smooth malice

Answer 106

When the smooth muscle contracts , the diameter of the artery narrows . THis alllws the body to control how much blood flows to different organs .

Question 107

Different between large and small muscles

Answer 107

Smaller arteries tend to have a greater proportion of SMOOTJ muscles than larger ateries . -that js bevause smaller attire is okay a great role in controlling blood pressure

Question 108

Next layer w shave is elastic fibres

Answer 108

Elastin fibres contain the protein elastin which can stretch . /when the heart contracts a surge of high blood pressure passes down the artery .

Question 109

-as fhe surge moves through , the elastic fibres stretch , fhen recoil , once the surge has passed .

Answer 109

Elastic recoil helps the blood moving smoothly forward , inbetween contractions of the heart .

Question 110

What is the. Entrap. about of the artery. Called ? Lumen

Answer 110

The linen is where the blood flows through. Lumen is lined with a thin layer of endothelial cells . - this presents a very smooth surface to reduce the friction as blood flows through .

Question 111

What do arteries branch into ?

Answer 111

Smaller blood vessels called arterioles .

Question 112

What is the job of the arterioles

Answer 112

The jobs of the arterioles is to deliverto to the capillaries . -the walls of the arterioles contain the same layers as arteries . -but as you will see they differe in their relative thickness .

Question 113

Blood pressure in arterioles

Answer 113

-the blood pressure is lower than in arteries and the effect of the pulse is weak . This means , that in arterioles the collagen - rich outer mager and the elastic kager are relatively thin compared to the arteries .

Question 114

What about the smooth muscle layer in arterioles

Answer 114

-is Much thicker than in arteries . - that is because arterioles are invovled in. Contracting the amount of blood passing through the capillaries .

Question 115

What happens when the smooth muscles on the arterioles contact

Answer 115

Blood flow through the cappillaties ir reduced . -scientists call this vasoconstriction /hwo ded fhe smooth muscle in the arteries relaxes . - blood flow through the capillaries increases , scientists call this vasodilation .

Question 116

When does vasodilation take place ?

Answer 116

Vasodilation takes place when an organ requires an in increased amount of oxygen .

Question 117

There is an extensive network of.Capillaries in every organ ?

Answer 117

As you can see , cappilladies are extensively branched and no body cell is very far from a capillary .

Question 118

What is a network of capillaries called ? What happens here ?

Answer 118

It is called a capillary bed . _the capillary hed is where substances are e change between the blood and body cells . -for example , oxygen and glucose diffuse from the blood to the body cells .

Question 119

How do waste products diffuse ?

Answer 119

Waste products such as carbon dioxide diffuse from the cells back to the blood .

Question 120

What does the extensive branching of capillaries provide ?

Answer 120

It provides a massive surface area for the exchange of. Materials . - the structure of capillaries has evolved tk maximise the rate of diffusion for molecules such as oxygen .

Question 121

What are the walls of capillaries like in the blood vessels ?

Answer 121

They ade extremely thin walls -in fact , the walls of the capillaries consist of a single layer of endothelial cells .

Question 122

What is the outside membrane like of capillaries ?

Answer 122

There is a thin membrane called the basement membrane . -consists of a single layer of cells . -making there is a short diffusion distance between the blood and the cells near the capillary .

Question 123

Why does the shift diffuse distance of the capillaries help ?

Answer 123

-it increases the rate of diffusion for molecules . -between the blood and the cells for example oxygen and carbon dioxide .

Question 124

What is the diameter of the capillary lumen like compared to. Red blood cell

Answer 124

It is only slighted higher than a red blood cell . —this means that when red blood cells pass through the capillary , they are pressed against the capillary wall .

Question 125

What is the effect of the red blood cells being pressed against the wall !

Answer 125

This reduces the distance for diffusion fo oxygen . -from the red blood s tk the tissue cells . - as the lumen of the capillaries is only slightly wider than a red blood cell . -meaning ew e blood cells reve Though capillaries in a single file. /

Question 126

What does it mean as red blood cells are travelling in single file ?

Answer 126

Because of this , red blood cells Love though the capillaries More Slowly than on arteries and arterioles . -this relative movement , increases the time available for molecules to diffuse in and out of the blood S

Question 127

Last adaptation of capillaries -if we look at the capillaries we can see gaps between endothelial cells .

Answer 127

These gaps allow fluid to pass out of the blood and scientists flak this tissue fluid . - tissue fluid ? Bathes the cells providing essential molecules such as glucose and amino acids .

Question 128

What do the gals in the capillary wall do ?

Answer 128

Allow white blood cells to leave the blood steam .

Question 129

Where does the blood goe after it passes though the capillary ?

Answer 129

It makes its way though very small veins called the venules .

Question 130

What do venules connect into . S

Answer 130

Venules connect into larger veins . - these veins carry deoxygenated blood to the venavava where it passes into the heart .

Question 131

How does blood in the Venules travel ?

Answer 131

Unlike arteries the blood in the Venules and veins flow under flow pressure and it is not travelling in pulses . -this means that the structure of the veins is different to the arteries .

Question 132

Why do veins have thinner s than arteries ?

Answer 132

This is because the walls of the veins do not need to withstand high blood pressure.

Question 133

Why do veins have a larger lumen ?

Answer 133

To carry a greater volume of blood compared to the arteries . - the smooth muscle layer and the elastic.are thinner in veins compared to the arteries .

Question 134

Rememebr , the blood on veins does not travel in pulses , so there is no elastic. Recoil .

Answer 134

However , just like arteries. (!: lumen of the veins has an internal lining of endothelial cells . The smooth surfaces reduces the friction between the old and the walls of the veins .

Question 135

Another important adaptation of grind er nerd yo learning that veins contain valves .

Answer 135

These valves keep the blood flowing in the forward direction. - rememebr , the blood vessels are moving back to the heart . Meaning blood may well be moving against gravity especially in legs and arms

Question 136

Problem of blood in the veins ?

Answer 136

It is travelling slowly and under low pressure q

Question 137

Quesfion ? What makes blood in the veins move back to the heart

Answer 137

Many veins are found lying between the skeletal muscles such as the large muscle of the arms and legs . - when these muscles contract e.g during normal movement , they stayed: between the veins lying between them .

Question 138

Blood flowing back to the heart part two

Answer 138

As we have seen xx veins have relatively thin walls . So when they squeeze they change shape . This squeezing forces the blood along . If the blood moves forward then the valves. Remain open XD s /however if the blood starts to move backwards fhen then the valves shut

Question 139

The combined egg feed kd the muscles Darryl’s and the grind Ed erll Ed the action of the valves

Answer 139

Helps to keep the blood moving towards the heart .

Question 140

What are the two main components of blood

Answer 140

Cells —> red blood cells which transport oxygen and white blood cells which play a role in the immunity . - blood cells are suspended and cell fragments platelets are in a water solution invovled in blood clotting called blood plasma .

Question 141

What does blood plasma contain

Answer 141

Blood plasma contains a range of dissolved molecules such as glucose and amino acids and ions such as sodium ions xx

Question 142

- blood plasma also cotnains dissolved oxygen which ?

Answer 142

Blood plasma also contains contains dissolved oxygen which doffusss out of the red blood cells. . - another very important of blood plasma are proteins such as Albanian scientists refer to these as plasma proteins. .

Question 143

What does the fluid do in the capillaries ?

Answer 143

The fluid passes out of the blood and bathed the tissue cells . - scientists call it tissue fluid .

Question 144

What does tissue fluid do ?

Answer 144

Tissue fluid leaves the bloood at the part of the capillary which is near the artery . / tissue fluid transfers molecules such as oxygen and tissue cells .

Question 145

What do waste meocluels from tissue cells do ?

Answer 145

Did exmsd co2 pass into the tissue fluid - the tissue fluid then truths bsck I my o the bloodstream. Af parts of the capillary which are near the vein ,

Question 146

Stage one of how tissue fluids move on and out of the blood (1)

Answer 146

Tissue fluid is forced out of the blood at the arterial end of the blood capillary . And returns back to the blood at the venous end of the blood capillary ,

Question 147

In order to understand the tissue fluid process we need to look at two competing factors

Answer 147

-. These are calllrd hydrostatic pressure and on proof oressure / structural end of capillary whrte tisdru fluid it reached - at the end of the capillary , the blood ha: .

Question 148

end of the capillary the blood has just passed into an arteriole

Answer 148

-because of this , the blood at the arterial and of the capillary is still under relatively high pressure , -scientists call this hydrostatic pressure

Question 149

what does hydrostatic pressure do ?

Answer 149

hydrostatic pressure tends to force fluid out of the blood into the tissue . -remember , in blood plasma , got plasma proteins like abeli .

Question 150

what do plasma proteins do ?

Answer 150

-plasma proteins are hydrophilic so they try to lower the water potential , of the blood plasma . -because the plasma proteins , there is a tendency for water to move back into the blood by osmosis . -scientists call this oncotic pressure .

Question 151

what is the hydrostatic pressure like at the arterial end ?

Answer 151

the hydrostatic pressure is greater than the oncotic pressure . -this means tissue fluid is forced out of the capillary through the gaps between the endothelial cells . -scientists call this process ultrafiltration .

Question 152

do proteins and blood plasma leave ?

Answer 152

no , they are too large so they remain in the blood plasma .

Question 153

What is the hydrostatic pressure like ,a t the venous end ?

Answer 153

The hydrostatic pressure is much lower , as a large amount of water has left the blood .

Question 154

how is the oncotic pressure like at the venous end ?

Answer 154

the oncotic pressure is still high due to the plasma proteins in the blood plasma . - so , because of this ,a t the venous end , the hydrostatic pressure is less than the oncotic pressure . Causing , water to move back to the blood by osmosis .

Question 155

Around 90% of the tissue fluid is reabsorbed back into the blood . what happens to the remaining ten percent .

Answer 155

the remaining ten percent of the tissue fluid drains into a series of blind-ended valves called lymph capillaries .

Question 156

What do lymph capillaries do ?

Answer 156

Lymph capillaries connect into large lymph vessels forming the lymphatic system . -the lymphatic fluid moves along to the lymph vessels are squeezed by nearby skeletal muscles .

Question 157

There are also valves in the lymph valves , why ?

Answer 157

valves into he lymph help to keep the lymph fluid . -eventually , the lymph fluid returns to the blood stream via blood vessels under the collar bone . -the lymphatic system also plays a role in immunity .

Question 158

what is the activity of insects ?

Answer 158

insects can be extremely active organisms with a very high oxygen demand . For examples , during flight .

Question 159

What is key about the gas exchange in insects ?

Answer 159

gas exchange systems in insects have evolved to provide oxygen directly to cells . -although insects do have a specialised transport system , this only tansfers nutrients not oxygen .

Question 160

What are insects covered in to aid gas exchange ?

Answer 160

insects are covered with a protective exoskeleton , made from the polysaccharide chitin .

Question 161

-gases such as oxygen and carbon dioxide cannot easily pass through the exoskeleton , so what does the exoskeleton have to aid this ?

Answer 161

-On the surface of the exoskeleton , we have small openings called spiracles . -Spiracles allow gases such as oxygen and carbon dioxide to diffuse into the body of the insect .

Question 162

what do spiracles lead to ?

Answer 162

spiracles can lead into a network of tubes called trachea . -The trachea are relatively wide tubes with a diameter of 1 mm . -trachea extends down and along an insects body .

Question 163

what are the walls of the trachea reinforced with ?

Answer 163

they are reinforced with spirals of chitin .

Question 164

what does the chitin do in the trachea ?

Answer 164

-the chitin prevents the trachea from collapsing example when an insect moves . -extending from the trachea are very fine tubes called tracheoles .

Question 165

give one adaptation of tracheoles

Answer 165

tracheoles have a diameter of around 1mm or less / So in fact , they are much mroe narrow then shown . -each trachea is a single cell that has extendfed to forma hollow tues .

Question 166

where do the tracheoles extend into ?

Answer 166

down in-between the insects body .

Question 167

another adaptation of tracheoles

Answer 167

-unlike trachea , tracheoles are not supported by chitin . Because , tracheoles have such a narrow diameter and have an extremely close to cells .. there is a very short diffusion distance for gases moving in between the cells and for gases moving between he cells and the tracheoles .

Question 168

another adaptation of tracheoles (2)

Answer 168

this allows , oxygen to diffuse rapidly from the air in the trachea , into the cells . -the oxygen is needed for aerobic respiration which produces the gas carbon dioxide . -the carbon dioxide can also rapidly diffuse back into the air in the tracheoles .

Question 169

Give a third adaptation of tracheoles

Answer 169

huge number of tracheoles provide a very large surface area for gas exchange . -this allows insects to maintain a very rapid rate of aerobic respiration (flight) -the ends of the trachea are filled with fluid aka tracheal fluid .

Question 170

what happens during intense activity in insects

Answer 170

cells undergo anaerobic respiration . -anaerobic respiration produces lactic acid , lowering the water potential of cells.# -This then causes the water in the tracheal fluid to move into the cells . -This reduces the volume of the trachea fluid drawing air into the tracheoles. -also means more tracheole surface is available for diffusion of carbon dioxide and oxygen

Question 171

In many insects , gas exchange is essentially an a passive process , explain ?

Answer 171

-oxygen diffuses down the co2 gradient and from high concentrations in the external air . -rate of diffusion decreases with distance meaning insects tend to be small . -smaller size insects reduces distance for diffusion to take place .

Question 172

What is the significant problem that insects face ?

Answer 172

Loss of water . -walls of the tracheoles are moist and the ends of the tracheoles contain tracheal fluid . -meaning water vapour can diffuse out of the insect via the spiracles .

Question 173

however , what is the spiracles surrounded

Answer 173

each spiracle is surrounded by a muscular sphiniser, this means that insects can reduce water loss by closing their spiracles . (e.g insects increase oxygen requirement )

Question 174

some insects have evolved to gas exchange

Answer 174

if we look at insects we can see we have three main body segments . -head -thorax -abdomen . -some insects can also contract muscles to change the volume of the thorax and the abdomen -causing pressure changes in the trachea and tracheoles , pushing air in and out this bulk movement of air is called mass transports .

Question 175

in some insects , the trachea contain expanding sections called air sacs . Explain what the air sacs do ?

Answer 175

changes in the volume of the thorax and the abdomen can squeeze the air sac causing air to move from the airspaces into the tracheoles . -insects can also use the oxygen in airsacs during ... when spiracles have been closed for water conservation .

Question 176

what do larger organisms have compared to smaller organisms ? 1

Answer 176

-larger organisms have a much lower surface area to volume ration with the vast majority of cells a large distancer form he surface of the organisms .

Question 177

what do larger organisms have compared to smaller organisms ? 2

Answer 177

also larger organisms often are very active and have a high demand for aerobic respiration . -meaning larger organisms cannot rely on diffusion alone for the diffusion if exchange in materials .

Question 178

we have already seen how insects fish and humans have specialised gas exchange systems. however , what is different in humans and fish ?

Answer 178

gases dissolve in blood , which acts as a transport system . -The blood , then moves around the circulatory system . transferring gases between the cells and gas exchange system .

Question 179

What other essential molecules does blood transfer ?

Answer 179

other essential molecules include glucose and amino acids . -when molecules are carried in a transport medium such as blood through a circulatory system scientists call this mass transport .

Question 180

stage one of circulatory system of fish

Answer 180

deoxygenated blood is pumped by the heart through blood vessels to gills .

Question 181

stage two of the circulatory system of fish

Answer 181

- in the gills , blood passes though narrow blood vessels called capillaries. -Oxygen diffuses from the water into the blood .

Question 182

stage three of the circulatory system of fish

Answer 182

the oxygenated blood now passes from the gills through the blood vessels to the body tissues .

Question 183

stage four of the circulatory system of fish

Answer 183

when it reaches the body tissues , the body again passes through narrow capillaries , where oxygen diffuses from the blood to the cells that need it .

Question 184

stage five of the circulatory system of fish

Answer 184

finally , the deoxygenated blood ,only returns in blood vessels back to the heart . -so blood only passes , through the heart once , as i moves around the circulatory system , scientists call this a single circulatory system .

Question 185

what is the problem with the circulatory system of fish ?

Answer 185

when blood leaves the heart , the pressure of the blood is high , and the blood is moving rapidly . -however blood then passes through narrow capillaries where oxygen diffuses from the blood to the cells that need it .

Question 186

stage six of the circulatory of fish

Answer 186

finally , the deoxygenated blood now returns in blood vessels back to the heart .-so blood only passes through the heart once . -as it moves around the circulatory system ,scientist call this a single circulatory system :)

Question 187

problem with single circulatory system ?

Answer 187

when the blood leaves the heat , the pressure of the blood is high , and this means blood is moving rapidly ,.. -however , blood then passes through two sets of narrow capillaries

Question 188

problem with single circulatory system ? (2)

Answer 188

firstly in the gills and secondly as it passes through the body tissue when the blood passes through the capillaries , blood flows down and looses pressure . -MEANING , once the blood passes through the gills it is moving relatively slowly . -This limits , how rapidly oxygen can be delivered to the body cells

Question 189

circulatory system in mammals (1)

Answer 189

deoxygenated blood is pumped under high pressures from the heart to the lungs .

Question 190

circulatory system in mammals (2)

Answer 190

in the lungs , blood passes through narrow capillaries and oxygen diffuses from the air into the blood .

Question 191

circulatory system in mammals (3)

Answer 191

as the blood , has passed through the capillaries is its moving at a relatively lower pressure .

Question 192

circulatory system in mammals (4)

Answer 192

however , now oxygenated blood returns back to the heart , pumping blood at high pressure around the body .

Question 193

circulatory system in mammals (5)

Answer 193

as it passes through the body , blood passes through the capillaries and oxygen diffuses to the body cells .

Question 194

circulatory system in mammals (6)

Answer 194

the low pressure , deoxygenated blood molecules it way , back to the heart and to be pumped again .

Question 195

what happens in a double circulatory system ?

Answer 195

in a double circulatory system , blood passes through the heart twice . -this ensures blood moves to the bodyt issues rapidly under high pressure . -so a double circulatory system can something oxygen more efficiently than a single circulatory system .

Question 196

where is blood contained in fish and mammals ?

Answer 196

blood is always contained in blood vessels as it travels to and from the heart . -scientists this is a closed circulatory system .

Question 197

what is a closed system ?

Answer 197

in a closed circulatory system , blood can move relatively rapidly , and the amount of blood passing to different organs can be controlled constricted by dilating blood vessels .

Question 198

WHat do insects have?

Answer 198

Insects have an open circulatory system . Insects do not contain blood .

Question 199

What do insects have instead of blood ?

Answer 199

Instead ,they contain a fluid called haemolymphs . -Haemolymph carried nutrients aka sugars but does not carry oxygen .

Question 200

Where is haemolymph situated , how is it transported ?

Answer 200

haemolymph is pumped out of the insect's heart and passes directly into the body cavity is called haemocoel .

Question 201

how is haemolymph transported ?

Answer 201

molecules are then transferred between the haemolymph and body cells and them haemolymph makes its way back into the heart . -key ; haemolymph is not carried in vessels so it si an exmpa,e of an open circulatory system .

Question 202

speed of haemolymph

Answer 202

As the haemolpyh is not carried in vessels it does not move rapidly around the isnect . -also the insect , does not easily change conc of hameolpyh moving to different parts of the body .

Question 203

What to arteries branch to form ?

Answer 203

arterioles

Question 204

what is the function of arterioles

Answer 204

arterioles carry the blood to the capillaries in each organism .

Question 205

how do molecules diffuse in the capillaries ?

Answer 205

In the capillaries , molecules diffuse from the blood to the cells example glucose and oxygen -other molecules diffuse from the body back to the heart .

Question 206

what direction do arteries carry the blood ?

Answer 206

away from the heart to the organs . -blood in the arteries is under high pressure . -when the heart beats , a surge even high blood pressure is pushed down in the arteries calls this pulse .

Question 207

blood is always moving forwards between heart beats for arteries .

Answer 207

...

Question 208

cross section of arteries -how thickkk is she

Answer 208

4-10mm is the cross section of a typical artery . -however , some arteries do have a wide diameter .

Question 209

what is the first thing to notice about artery walls ?

Answer 209

artery walls are relatively thick . -this allows the artery to withstand the high pressures of the blood . -the walls of the arteries consist of several layers .

Question 210

what is the outer layer of the artery like ? -what does it have that helps w structure ?

Answer 210

the outer layer is rich in fibrous protein collagen . Which we looked at previously . -Collagen plays a role structurally , strengthening the artery wall against the pressure of the blood .

Question 211

explain the next layer of the artery that contains smooth muscle , not like isaacs bum ?

Answer 211

-when the smooth muscle contracts when isaac needs to take a dump , the diameter of the artery narrows . -this allows body to control how much blood flows to different organs , like isaac controlling his plops .

Question 212

what do smaller arteries have compared to larger arteries and why ?

Answer 212

smaller arteries tend to have a GREATER proportion of smooth muscles than larger arteries . -That's because smaller arteries play a great role in controlling bloodflows .

Question 213

next layer we have in arteries is elastic fibres , what do they do part one

Answer 213

elastic fibres contain the protein elastin , which can stretch . -when the heart contains a surge of high pressure , passes down the artery .

Question 214

elastic fibres part two

Answer 214

-as the surge moves through , the elastic fibres stretch , then recoi . one of the surges have passed . -elastic recoil , helps the blood move smoothly forward , inbetween contractions of the heart .

Question 215

what is the central cavity of the artery called , what happens here ?

Answer 215

the central cavity of the artery is called the lumen . -the lumen is where the blood flows though lumen is lined with a thin layer of endothelial cells. -this presents a very smooth surface to reduce friction as blood flows throuh .

Question 216

what do arteries branch off into ? what do they do

Answer 216

arteries branch into smaller arterioles . -arteries branch is to deliver blood to the capillaries . -the wall of the arterioles contain the same layer as arteries . -but they differ in their relative thickness

Question 217

what is the blood pressure like in the arterioles ? -What is the effect of this on the pulse, what does this mean ?

Answer 217

;-The blood pressure is lower than in the arteries . -the effect of this is that the pulse is weaker .

Question 218

What does a weaker pulse mean in the arterioles ?

Answer 218

This means that in the arterioles the collagen - rich outer layer . -rich outER LAYER and the elastic layer are relatively thin compared to the cells .

Question 219

what is the thickness of the connective tissue and smooth muscle layer like and why ?

Answer 219

it is relatively thicker in arterioles compared to arteries . -That's because arterioles are involved in controlling the amount of blood passing through the capillaries .

Question 220

What happens when the smooth muscle in the arteries contract ?

Answer 220

-Blood flows through the capillaries is reduced . -scientists call this vasoconstriction .

Question 221

what happens when the smooth muscles in the arteries relax ?

Answer 221

-blood flow increases through the capillaries scientists call this vasodilation .

Question 222

when does vasodilation happen ?

Answer 222

takes place when an organ requires an increased amount of oxygen .

Question 223

extensive networks of capillaries adaptations

Answer 223

capillaries are extensively broad and no body cell is very far from a capillary . -a network of capillaries is called a capillary bed .

Question 224

What happens in the capillary beds ?

Answer 224

-The capillary beds are where substances are exchanged between the blood and body cells . -for example , oxygen and glucose diffuse from the blood into the body cells . -while , waste products such as carbon dioxide diffuse from the cells back into the blood .

Question 225

what does the extensive branching of capillaries provide ? -give the adaptation

Answer 225

-the extensive branching provides a massive surface area for the exchange of materials . -the structure of capillaries has evolved to maximise the rate of diffusion for molecules such as oxygen .

Question 226

what are the thickness of the walls of the capillaries like ?

Answer 226

capillaries have extremely thin walls. -the walls consists of single endothelial cells .

Question 227

what is on the outside of the capillary walls ?

Answer 227

the outside of the capillary walls , there is a thin membrane called the basement membrane .

Question 228

what is the advantage of thin walls for capillaries ?

Answer 228

-as the capillary wall consists of a single layer of cells , this means that there is a very short diffusion distance between the blood and the cells near the capillary / -this short distance increases the rate of diffusion of molecules between the blood and the cells for example oxygen and carbon dioxide .

Question 229

what is the diameter of the lumen of the capillary like , and what does this mean ?

Answer 229

-the diameter of the capillary lumen is only slightly bigger than red blood cells . -this means that when red blood cells pass through the capillary , they are pressed against the capillary wall .

Question 230

adaptations of the lumen of the capillary part two

Answer 230

-this reduces the distance for the diffusion for the distance of diffusion of oxygen ., -from the blood cells to the tissue cells .

Question 231

how do blood cells travel through the capillary ?

Answer 231

-this means red blood cells travel through capillaries in single file . -because of this , red blood cells move through the capillaries more slowly in arteries than in arterioles . -This relatively slow movement , increases the time available for molecules to diffuse in and out of the b lood /

Question 232

what is the final adaptation of capillaries

Answer 232

-if we look at the capillary wall , we can see small gaps between the endothelial cells . -these gaps allow fluid to pass out of the blood , scientists call this tissue fluid .

Question 233

What does tissue fluid do ?

Answer 233

tissue fluid , bathes the cells , providing essential molecules such as glucose and amino acids .

Question 234

What do gaps in the capillary wall do ?

Answer 234

the gaps in the capillary wall , also allow white blood cells to leave the bloodstream

Question 235

once blood passes through the capillaries , where does it go ?

Answer 235

-It makes its way through very small veins called venules .

Question 236

where do veins connect to ?

Answer 236

venules , then connect into larger veins . -these veins carry deoxygenated blood into the vena cava , where it passes into the heart .

Question 237

what is the pressure of the blood like in the veins and venules .

Answer 237

it is under low pressure , and it is not travelling in pulses . -this means that the structure of the veins is different to arteries .

Question 238

why do veins have thinner walls ?

Answer 238

veins have thinner walls than arteries as the walls of the veins do not need to withstand high blood pressure .

Question 239

what is the lumen of the veins like and why ?

Answer 239

veins have a larger lumen and carry a greater volume of blood compared to arteries .

Question 240

what are the walls like in veins ? (endothelial etc )

Answer 240

the smooth muscle layer and the elastic layer are thinner in veins compared to the arteries . -As the blood in the veins does not travel in pulses , so there is no elastic recoil .

Question 241

What is the internal lining of the lumen like ?

Answer 241

the internal lining of endothelial cells . -the smooth surface reduces friction between the blood and the walls of the vein .

Question 242

veins contain valves , explain why

Answer 242

-these valves keep the blood flowing in the forward direction . -remember , blood in veins is moving back to the heart , meaning blood may well be moving against gravity example in the legs and arms .

Question 243

problem , blood is travelling in veins at a relatively low pressure . -question what makes blood in veins move back to the heart ?

Answer 243

-many veins are found lying between skeletal muscles , such as the large muscles in arms and legs . -when the muscles contract , during movement , they squeeze between he veins lying between them .

Question 244

problem , blood is travelling in veins at a relatively low pressure . -question what makes blood in veins move back to the heart ? part two

Answer 244

as we have seen , veins have relatively thin walls , so when they squeeze , they change shape . -this squeezing , forces the blood along .if the blood moves forward then the valves remain open . -however if the blood starts to move backward then the valves shut . -tis combined effect of the muscles squeezing and the veins , as well as the action of the valves helps the blood move towards heart ,

Question 245

what is another factor that makes blood in the veins move back to the heart ?

Answer 245

when we inhale , the pressure of the chest cavity decreases . -this decrease in pressure , helps t he blood in the chest veins to move forwards towards the heart .

Question 246

blood has two components , what is the first component ?

Answer 246

cells , red blood cells which transport oxygen and while blood cells play a role in immunity , blood cells are suspended and cell fragments and platelets in watery solutions , are involved in blood clotting , scientist call this blood plasma .

Question 247

What doe

Question 248

What does blood plasma contain ?

Answer 248

it contains a range of dissolved molecules such as glucose , amino acids and ions such as sodium ion na+ .

Question 249

what else does blood plasma contain ?

Answer 249

blood plasma also contains dissolved oxygen which diffuses out of the red blood cells . -another very important part of blood plasma are proteins such as albumin . -scientists refer to these as plasma proteins .

Question 250

what is the fluid like in the capillaries ?

Answer 250

fluid is pushed out of the blood and bathes the tissue cells . -scientists call this tissue cells .

Question 251

what do waste products do in the tissue cells ?

Answer 251

waste molecules from the tissue cells such as co2 , pass into the tissue fluid . -the tissue fluid then returns back into the blood stream and passes out of the capillary which is near the vein .

Question 252

how does tissue fluid move in and out of the blood part one ?

Answer 252

-tissue fluid is forced out of the blood at the arterial end of the blood capillary and reutrn back to the blood at the venous end of the capillary /

Question 253

in order to understand how tissue fluid is moving need to understand two competing factors , what are they ?

Answer 253

hydrostatic and oncotic pressure .

Question 254

what happens at the arterial end of the capillary ?

Answer 254

blood has just passes through an arteriole . -because of this , the blood at the arterial end of the capillary , is still under relatively high pressure . -scientists call this hydrostatic pressure ?

Question 255

what way does hydrostatic pressure push blood ?

Answer 255

hydrostatic pressure tends to force fluid out of the blood and into the tissue . -remember in blood plasma , got plasma proteins as alb thatthing .

Question 256

what do plasma proteins do in relation to hydrostatic pressure.

Answer 256

plasma proteins are hydrophilic so they lower the water potential of the blood plasma . - because of this , the plasma proteins , there is a tendency for the water to move back into the blood by osmosis . -scientists call this oncotic pressure .

Question 257

what is the blood pressure like at the arterial end of the capillary ?

Answer 257

the hydrostatic pressure is greater than the oncotic pressure . -this means that tissue fluid is forced out of the capillary through the gaps between the endothelial cells . scientist call this process ultrafilitiriatiom /

Question 258

does blood cells and plasma proteins leave the blood ?

Answer 258

no ,t hey are too big

Question 259

what happens at the venous end of the capillary ?

Answer 259

hydrostatic pressure is much lower as a large amount of water has left the blood . -however , oncotic pressure is still high due to plasma proteins in the blood plasma , because of this , at the venous end , the hydrostatic pressure is less than the oncotic pressure . -causing water to move in by osmosis into the blood

Question 260

how much of the tissue fluid is reabsorbed back into the blood

Answer 260

around 90 %

Question 261

what happens to the remaining ten percent of tissue fluid ?

Answer 261

it drains into a series of blind-ended vessels called lymph cappillaries .

Question 262

what happens in lymph capillaries

Answer 262

-lymph capillaries connect into large lymph vessels forming the lymphatic system . -lymphatic fluid something when lymph vessels are squeezed by nearby skeletal muscles .

Question 262

what do valves in the lymph valves do ?

Answer 262

they gelp to keep the lymph fluid move forward . -eventually , the lymph fluid returns to the blood system via blood vessels under the ...

Question 263

where else does the lymphatic system play a crucial role ?

Answer 263

in immunity .

Question 264

what are red blood cells also known as and what do they do ?

Answer 264

erythrocytes , and they transport oxygen .

Question 265

adaptation one of erythrocytes ?

Answer 265

they have a biconcave structure giving them an increased surface area to volume ration , allowing oxygen to diffuse in and out rapidly .

Question 266

second adaptation of erythrocytes

Answer 266

each erythrocyte contains around 300 million molecules of the oxygen carrying protein haemoglobin .

Question 267

third adaptation of erythrocytes

Answer 267

although erythrocytes initially have a nucleus , this is lost before the erythrocytes enter circulation . -absence of this means more erythrocytes volume is available to carry haemoglobin .

Question 268

describe the structure of haemoglobin

Answer 268

4 polypeptide chains . -each binds to a prosthetic group haem -iron ion fe2+ -so it is an example of a conjugated protein .

Question 269

check sheet for equation , and explain it -is it a reversible reaction ? explain the effect of this

Answer 269

each of the fe2+ in the haem molecule can combine with one molecule of oxygen l. -as there are four haem groups in each haemoglobin molecule . --as it is a reversible reaction , oxyhaemoglobin can also release the oxygen when required .

Question 270

how can we measure the amount of oxygen that combines with haemoglobin ? what does this thing show

Answer 270

-oxygen dissociation curve . -on the y axis shows the percentage saturation of haemoglobin with oxygen . x axis is partial pressure of oxygen . -as oxygen is a gas wee do not say it is the CONC of oxygen

Question 271

what shape does the graph have ?

Answer 271

s shape - sigmoid curve

Question 272

what does the graph tell us about haemoglobin ?

Answer 272

-sample of haemoglobin , as we increase the kpa , the percentage saturation of haemoglobin increase restively slowly .

Question 273

what does star one of the oxygen dissociation curve .show

Answer 273

at around 4 kpa , 25% saturation , each haemoglobin molecule -bound to ne oxygen molecule . -meaning low partial pressure of oxygen has haemoglobin has a low AFFINITY for oxygen .

Question 274

what does affinity mean

Answer 274

how strongly the oxygen binds to the haemoglobin

Question 275

what happens if one oxygen molecule binds ?

Answer 275

the affinity of haemoglobin of oxygen increases , and becomes much easier to bind to further oxygen molecules .

Question 276

what will happen if we increase the partial pressure of oxygen to around 7 KPA

Answer 276

WEACHIEVE 75% SATURATION , AKA 2 more oxygen molecules have bound .

Question 277

can explai8n the 75% saturation by looking at the structure of haemoglobin molecule

Answer 277

remember , haem contians 4 polypeptides . -each polypeptide contains 4 haem groups whhich can bind to oxygen . -if there is NO oxygen , then rthe haem graph will show low affinity for oxygen moelcules .

Question 278

what does a low affinity for oxygen mean ?

Answer 278

this means it takes a relatively large partial pressure for oxygen , so the first oxygen molecule can bind to a haem group . -however , when one oxygen binds , the quaternary structure of the haemoglobin molecule changes . -this now increases the affinity of the haem groups for oxygen .

Question 279

so binding more oxygen molecules ...

Answer 279

only ,,, protein haemoglobin .

Question 280

when does partial pressure of oxygen decrease ?

Answer 280

-as tissue cells take up oxygen for aerboic respiration .

Question 281

-at a certain partial pressure , an average of oxygen molecule can now what , and what does this mean ?

Answer 281

one oxygen molecule can now unload each haemoglobin molecule . -when one oxygen molecule unloads , this changes the quaternary structure of the haemoglobin and the effect of this is to reduce the affinity of the haem groups for oxygen .

Question 282

what happens to the pressure of the blood , if the blood passes though a very active site for example muscles

Answer 282

then the partial pressure of oxygen will fall even further . -as the haemoglobin has a reduced affinity for oxygen it is now more easy for oxygen molecules to unload .

Question 283

another factor that needs to be considered is the partial pressure of co2 , and the effect it has on the oxygen dissociation curve .

Answer 283

-highlighted line in yellow , shows the carbon dioxide . -shows haemoglobin when the co2 , is relatively low , partial pressure of c02 increased , in muscle tissue .

Question 284

what way does co2 , shift the curve ?

Answer 284

it shifts the oxygen dissociation curve to the right . -what this means is that co2 k,, causes the oxygen affinity of haemoglobin o decrease , scientist call this the bohr effect .

Question 285

explain the bohr effect using the graph

Answer 285

if the partial pressure of co2 is low , then the haemoglobin is 75% saturated at a partial pressure of o2 at 7kpa ;/

Question 286

what is the partial pressure of oxygen , when partial pressure of co2 is high ?

Answer 286

then the haemoglobin is only 25 % saturated at the same partial pressure of 02 ,a s before . -so the effect of co2 , is to reduce the affinity of haemoglobin for oxygen .

Question 287

start with this cardd - a relatively small increase in the oxygen partial pressure , what do scientist call this ?

Answer 287

positive cooperativity .

Question 288

why does the fourth haem group , only bind to oxygen at a fairly high partial pressure ?

Answer 288

that is because , 3 of the 4 haem groups have already been filled . -so the chances of an oxygen molecule colliding with a 4th haem gorop is relatively low .

Question 289

where is the partial pressure of oxygen high , and what happens here ?

Answer 289

-in the alveoli , the partial pressure of oxygen is high and the haemoglobin , in red blood cells is around 97% saturated . -

Question 290

-however m at a certain point , one oxygen molecule now unloads from the haemoglobin molecule . -what does this unloading do to the structure .

Answer 290

-however m at a certain point , one oxygen molecule now unloads from the haemoglobin molecule . -the effect of this is to decrease oxygen affinityo f the remaining haem groups .

Question 291

what will happen if the red blood cells moves into more active tissue ?

Answer 291

then the oxygen partial pressure will be even lower and two more oxygen molecules will rapidly unload from the haemoglobin molecule .

Question 292

what will happen when the final oxygen molecule unloads ?

Answer 292

-the partial pressure of oxygen has to be very low . -this is unlikely to happen under normal conditions but it could take place in very active tissue example muscle tissue during intense exercise .

Question 293

if we plot the percentage of haemoglobin with oxygen against the partial pressure , what do we get ?

Answer 293

-oxygen dissociation curve . -aka affinity of haemoglobin or oxygen , how strongly haemoglobin bind to oxygen depends on the partial pressure of oxygen .

Question 294

check sheet for rest .

Answer 294

...

Question 295

what is the first important effect co2 has

Answer 295

haemoglobin , has a higher affinity for oxygen , in conditions where the partial pressure of co2 is low , in the left hand side .

Question 296

In what places will oxygen and carbon dioxide be high ?

Answer 296

-in he lungs , haemoglobin has a high level of oxygen saturation . -however , partial pressure of co2 , will be high when undergoing aerobic respiration , in muscle tissue .

Question 297

in blood , what can carbon dioxide form ?

Answer 297

it can form the , the acidic molecule carbonic acid . -carbonic acid , released hydrogen ions h+ , the h+ combines with haemoglobin ,, causing the quaternary structure of haemoglobin to change . -therefore , haemoglobin , has a lower affinity for oxygen , causing haemoglobin o unload oxygen more easily .

Question 298

how is the circulatory system of a foetus linked with maternal circulatory system ?

Answer 298

in the placenta , the fetal blood and the maternal blood pass closely to each other but they do not mix .

Question 299

what does the maternal blood have compared to the foetal blood ?

Answer 299

-the maternal blood has a high level of oxygen than foetal blood -this causes , oxygen to diffuse across the placenta and into the foetal blood . -to make oxygen transfer more efficiently , foetal haemoglobin is different to adult haemoglobin .

Question 300

look at the oxygen dissociation curve difference between foetus and an adult . What does it show ?

Answer 300

-oxygen dissociation curve has shifted to the left compared to adult haemoglobin . -meaning foetal haemoglobin has a higher affinity for oxygen , then adult haemoglobinn .

Question 301

what does this higher affinity for oxygen do ?

Answer 301

it increases , the oxygen transfer across the placenta from the maternal haemoglobin to the foetal haemoglobin .

Question 302

notice that oxygen affinity of fetal haemoglobin is only slightly greater than in adult haemoglobin , why is this ?

Answer 302

-if the foetal haemoglobin had a very high oxygen affinity , this could prevent it from unlading oxygen the foetal tissues . -so the oxygen affinity is only slightly greater than in adult .

Question 303

however , in foetal haemoglobin , to of the polypeptide changes are different than in adult haemoglobin .

Answer 303

due to this difference in gene , explain the foetus compared to adult . -this difference , in polypeptide chains in the fetal haemoglobin means it has a higher oxygen affunity .

Question 304

what is the last factor to consider about foetal blood ?

Answer 304

carbon dioxide from the foetus , dissolve's into the maternal blood . this carbon dioxide lowers the oxygen affinity for maternal haemoglobin . -combined with a higher oxygen affinity of foetal haemoglobin , this makes oxygen transfer from maternal blood to foetal blood extremely efficient .

Question 305

all cells produce co2 , during what and what happens to the co2 ?

Answer 305

co2 , can be added to respiring tissues in the lungs where it is broken down .

Question 306

what is one way carbon dioxide can be transported in the blood ?

Answer 306

around 5% of the carbondioxide dissolves directly in the blood plasma

Question 307

what is another way carbon dioxide can be transported in the blood

Answer 307

around 20 % forms a compound with haemoglobin molecules in the red blood cells . -remember , haemoglobin contains 4 polypeptide chain . -in each of polypeptides the one amino aid has a free amino group . -each of these amino groups can react with a molecule of co2 , so one molecule of haemoglobin can react with 4 molecules of co2 .

Question 308

look at the reversible reaction , when blood passes through respiring tissue -how does co2 , get broken down in this reaction ?

Answer 308

the lack of carbon dioxide is high and Carboxyhaemoglobin , forms . -however , in the lungs , the level of carbon dioxide is low and the carboaminohaemoglobin breaks down releasing co2 .

Question 309

now we have seen how around 25 & of the co2 is in the blood . -how is the remaining 75 % transported ?

Answer 309

as hydrogen carbonate ion sin the blood plasma .

Question 310

explain the next reversible reaction with carbon dioxide and water

Answer 310

-as you can se , this is a reversible reaction , this reaction usually takes place slowly , however , the red blood cells contain an enzyme which speed up the reaction .

Question 311

what is the enzyme called , and what does it do ?

Answer 311

carbonic anhydrase . -when co2 , diffuses into red blood cells it rapidly . forms carbonic acid . -by cobverting co2 k into carbonic acid . -this ensures the level of c02 , in red blood cells is low .

Question 312

what does a low concentration of co2 in red bloood cells mean ?

Answer 312

- meaning there is a steep concentration gradient for co2 . -due to the steep concentration gradient , there is a high rate of diffusion of co2 , inot the blood cells .

Question 313

once the carbonic acid is formed , what does it dissocisate into ?

Answer 313

-hydrogen ions and hydrogen carbonate ion .

Question 314

what happens to the hydrogen carbonate ion ?

Answer 314

-the hydrogen carbonate ion now diffuses out of the red blood cells into the blood plasma .

Question 315

what is the problem with the hydrogen carbonate ion ? and how do we prevent this

Answer 315

-hydrogen carbonate ion has a negative charge . -when the hydrogen carbonate ion now diffuses out of the red blood cell this creates a charge something .

Question 316

-what do we do to pevent the charge for hydrogen carbonate tion ?

Answer 316

to prevent this hdyrogen carbonate ion diffuses out of red blood cell . -negative chlorate ion diffused out of he red blood cell , the chll prvents the charge imablance in red blood cell .

Question 317

we also release hydrogen ion , what does that do to the blood ?

Answer 317

-hydrogen ion , causes the ph of the blood to falls . -to prevent htis , haemoglobin binds to thehydrogen ions aso haemoglobina cts as buffer we call it lactic acid .

Question 318

-when the level of of carbon dioxide is high , for example in respiring tissue , what happens ?

Answer 318

-the carbon dioxide forms carbonic acid and then the hydrogen carbonate ions .

Question 319

however mw hen the level of carbon dioxide is low , for example in the lungs what happens ?

Answer 319

-in this case , the level of carbon dioxide is low , so hydrogen carbonate ions diffuse back into the red blood cells in exchange for chloride ions . -the hydrogen carbonate ions then combine with hydrogen ions to reform carbonic acid .

Question 320

-then when is carbonic acid broken down by

Answer 320

carbonic anhydrase , forming carbon dioxide . -carbon dioxide diffuses out of the red blood cells and into the blood p0lasma . -once in the blood plasma , the co2 , ca be exhaled from the lungs where the blood passes though the alveoli .

Question 321

once in the blood plasma , what happens to the co2

Answer 321

the co2 , can be exhaled from the lungs ,when the blood passes through the alveloi .

Question 322

how s the heart always shown ?

Answer 322

-heart is always shown as if you are facing the person . -lhs of the heart is shown as the right of the diagram and vice versa .

Question 323

what is heart formed from

Answer 323

cardiac muscles and have two completely separate sides .

Question 324

what are the top two chambers of the heart ?

Answer 324

-top two are called atria , these have relatively thin muscular walls .

Question 325

what are the bottom two chambers of the heart ?

Answer 325

bottom two are called ventricles . -ventricles have much thicker muscular walls than atria .

Question 326

how are the atria separated from the ventricles /

Answer 326

by the atrioventricular valves .

Question 327

what is the left and right av valve called ?

Answer 327

-called the bicupsid valve . -the right av valve is called the trcapsid valve .

Question 328

what are the valves attached to ?

Answer 328

they are attached to tendons which ensure the valves open in the right direction .

Question 329

the right and left side of the heart are completely separated by what ,and what does it do ?

Answer 329

by a wall called the septum . -the septum prevents any blood from passing directly between two sides of the heart .

Question 330

transport of blood part one

Answer 330

deoxygenated blood , enters the right atrium through the vena cava . -the vena cava has two branches .

Question 331

what does the superior vena cava do ?

Answer 331

the superior vena cava brings blood from the head and upper parts of the body .

Question 332

what does the inferior vena cava do ?

Answer 332

brings blood from the lower parts of the body .

Question 333

transport of blood part two

Answer 333

the deoxygenated blood is now pumped from the right atrium to the right ventricle . -the right ventricle now pumps the deoxygenated blood out of the heart to the lungs through the pulmonary artery /

Question 334

transport of blood part three

Answer 334

in the lungs , the blood becomes oxygenated , oxygenated blood now returns from the lungs back to the heart inthe pulmonary vein .

Question 335

transport of blood part 4

Answer 335

the pulmonary vein brings blood into the left atrium . -blood then passes into the left ventricle which passes the blood out of a large blood vessel called the aorta .

Question 336

transport of blood part 5

Answer 336

the aorta , transfers deoxygenated blood to all the other parts of thebodt including the heart .

Question 337

what is the right side of the heart like compared to the left ?

Answer 337

you can see that the left ventricle is a thicker muscular wall than the right ventricle . -that is because , the left ventricles pump blood around the whole body . -whereas the right ventricles only pump blood to the lungs

Question 338

what parts contain valves ?

Answer 338

the pulmonary artery and the aorta

Question 339

what are the coronary arteries ?

Answer 339

-blood vessels that directly branch from the aorta . -aka - coronary artery , this supplies the heart muscle with oxygen and nutrients .

Question 340

how is the heart beat initiated ?

Answer 340

the heart beat is initiated from within the heart itself . -aka ,the heart does not need an external signal to beat . -as the heart triggers its own beat , scientists say its myogenic .

Question 341

where is the pacemaker ?

Answer 341

pacemarker is in the right astrium -sinatrial node san aka pacemaker .

Question 342

how does a pacemaker work ?

Answer 342

- the cells in the san , depolarise , they become electrically excited . -this triggers a wave of electrical excitation to spread across the atria ,causing the atria to contract .

Question 343

what is the contraction of the atria called

Answer 343

the systole .

Question 344

the wave of electrical excitation , crossing the atria cannot directly pass down the ventricles , why ?

Answer 344

that is because the ventricles are separated from the atria , by a layer of non-conducting tissue . -this layer of tissue , will not pass the electrical excitation through it .

Question 345

between the atria , there is another group of specialised cells , what are they called and what do they do ?

Answer 345

atrioventricular node - avn . -the avn is connected to conducting fibres called parylune fibres .

Question 346

what do the parlyne fibres do ?

Answer 346

initially , the parlyne fibres are budnled together , scientits call this the b unde . -

Question 347

what do the parlyne fibred so ?

Answer 347

-run down to the apex . -or abse of the heart and then up the walls of the ventricles .

Question 348

what do the atrioventricular valves do ?

Answer 348

they detect the elastic sxcitation passing over the atria . -after a short delay , the avn , then transmits the electrical excitrtation down the parlyne fibred , this eletrical excitation causes the ventricles to contract .

Question 349

where do the ventricles contract ?

Answer 349

from the apex upwards . -this ensures maximum volum eof blood is pumpd out of the ventircles .

Question 350

why is there a slight delayw hen avn triggers electrical excitation ?

Answer 350

this ensures that the ventricles contract after the atria has contracted .

Question 351

what is blood moving to the heart in what cycle ?

Answer 351

the cardiac cycle

Question 352

key word in cardiac cycle - systole , what does it mean ?

Answer 352

contracting -- example atria systole , contraction of the atria .

Question 353

key word in the cardiac cycle - diastole , what does it mean ?

Answer 353

diastole means relaxing , example ventricualr diastole , relaxation of the ventricles .

Question 354

cardiac cycle stage one

Answer 354

both the atria and ventricles are in diastole , aka they are relaxed . -blood flows into the atria via the vena cava and pulmonary vein . -causing the pressure in the atria to rise .

Question 355

cardiac cycle stage two

Answer 355

at a certain point ,the pressure in the atria , is greater than the pressure in the ventricles , causing the atrioventricualr valves to open . -allowing blood to flow down from the atria into the ventricles .

Question 356

cardiac cycle part three

Answer 356

now , the atria contract ,a ka atrial systole takes place . -this pushes the remaining blood from the atria down to the ventricles .

Question 357

cardiac cycle part four

Answer 357

-after a short period of time , the ventricles contract aka they enter ventricular systole ., -pressure in the ventricles now rise rapidly . -because the ventricular pressure is now greater than the arterial pressure , the atrioventricular valve closes . -

Question 358

why does the atrioventricular valve close ?

Answer 358

as this prevents any blood from moving back into the atria from the ventricles .

Question 359

cardiac cycle part five

Answer 359

the semilunar valves and in the pulmonary aorta are all open .

Question 360

cardiac cycle part six

Answer 360

blood is pumped out of the ventricles to the heart . -you will notice when the ventricles contracted ,t he atria are relaxed.

Question 361

cardiac cycle part seven

Answer 361

finally , the ventricles relax . aka they enter ventricular diastole . -at some point , the pressure in the ventricles falls below the pressure in the pulmonary artery and the aorta .

Question 362

cardiac cycle part 8

Answer 362

this causes , the semilunar valve to shut . -preventing blood from flowing back into the ventricles , at this point hear is ready to enter next cardiac cycle .

Question 363

scientists have determined the blood pressure in different places of the heart during the cardiac cycle , what does the graph show ?

Answer 363

-graph applies to the left side of the heart . -top graph shows the pressure changes taking place . -bottom graph shows valve of left ventricle .

Question 364

reference keys

Answer 364

top graph first , shows pressure in left atrium . black line pressure in left ventricle blue line shows pressure ina orta - which takes blood out of the ventricle .

Question 365

(focus on black line ) --> what does star one show ?

Answer 365

at the start , the left atrium is undergoing systole . -aka contracts , causing the pressure in the left atrium to increase . -the atrioventricular valve is also open , so blood flows down the left ventricle causing pressure of left ventricle to increase .

Question 366

what does star two show (black line focus )

Answer 366

now the left ventricle contracts , aka enters systole , pressure in the elft ventricle massively increases . -as the pressure in the left ventricle is now greater than in the left atrium ,t he atrioventricular valve shuts .

Question 367

what does star three show ?

Answer 367

when the pressure in the left ventricle is now greater than in the aorta , the semi-lunar valve in the aorta opens . -blood now flows out of the left ventricle through the aorta .

Question 368

what does star four show

Answer 368

the pressure in the left ventricle now falls as the blood is leaving .

Question 369

what does star five show ?

Answer 369

at a certain point , the pressure in the left ventricle is less than in the aorta . -now the semilunar valve in the aorta closes preventing blood from being drawn back into the ventricle .

Question 370

what hap[pens while the left ventricle is contracting ?

Answer 370

the left atrium is relaxing , (yellow line ) . -this means the left atrium is now refilling with blood .

Question 371

focus on yellow line part two

Answer 371

the left ventricle begins to relax , causing the pressure of the left ventricle to fall . -eventually , the pressure in the left ventricle falls bellow the pressure in the left atrium . -at this point ,the atrioventricular valve opens and blood begins ro now move into the left ventricle form the left atrium .

Question 372

what happens as the atria and ventricles refill ?

Answer 372

the heart is ready to enter the next cardiac cycle /

Question 373

what does star six do ?

Answer 373

- we can see , blood volume increased as it is pumped into the left ventricle where the atrium contracts .

Question 374

what does star seven show

Answer 374

when the left ventricle contracts , the blood valve falls as blood moves out through the aorta.

Question 375

what does star eight show

Answer 375

finally the blood volume increases and again , when left ventricle relaxes . blood flows down from left atrium l

Question 376

How can we analyse the electrical activity of the heart ?

Answer 376

by attaching electrodes to the surface of the skin .

Question 377

check the sheet , what does the pattern show , and what does it tell us ?

Answer 377

-the resulting trace is called an electrocardiogram / ECG -pattern of ecg tells us what is taking place in the heart , this can be divided into three sections .

Question 378

what does the p wave show ?

Answer 378

p wave shows the contraction of the atria , aka atrial systole

Question 379

what does the qrs wave show ?

Answer 379

it shows the contraction of the ventricles aka ventricular systole .

Question 380

what does the t wave show ?

Answer 380

T wave shows the relaxation of the ventricles aka ventricular diastole .

Question 381

how does the ecg correlate with the cardiac cycle ?

Answer 381

-we can map the ecg onto the graph we saw of pressure changes during the cardiac cycle . -can see the different stages during a heart beat .

Question 382

check the ecg , what does each division show , and how is heart rate measured ?

Answer 382

-each division shows 0.2 seconds , The heart rate is showed in beats per minute

Question 383

how do we calculate bpm ?

Answer 383

-measure the time take for one heart beat . -to do this , measure the time between the start of the p wave and the start of the next p wave .

Question 384

Some people have a slow resting heart rate , what is this called .

Answer 384

-If the heart rate is below 60 bpm , this s called bradycardia .

Question 385

when can bradycardia happen ?

Answer 385

bradycardia can happen due to athletic training , -which increases the stroke volume of the heart .

Question 386

what is the bpm like in bradycardia ,and why ?

Answer 386

-as the heart pumps a greater blood volume per beat , the number of bats per minute decreases .

Question 387

why may someone develop bradycardia ?

Answer 387

some people may develop bradycardia as a result of a disease , these people may require an artificial pacemaker .

Question 388

some people have a heart rate greater than 100 bpm , what is this called ?

Answer 388

This is called tachycardia . -tachycardia , can be caused by short term effects such as fear , panic or exercise .

Question 389

what cab long term tachycardia be caused by ?

Answer 389

problems with the sinoatrial node , or other medical problems . -in this surgery or drugs may be required .

Question 390

what is an example of an ectopic heartbeat ?

Answer 390

an ectopic heartbeat is an extra heartbeat , that is not part of the heart's usual rhythm . -heart contracts again before first contraction has finished . This is then followed by a short pause , before the normal rhythm continues .

Question 391

what is the severity of an ectopic heartbeat ?

Answer 391

ectopic heartbeat is relatively common and does not pose any health risks . -however , if a person experiences an ectopic heartbeat , that might indicate a more serious heart condition .

Question 392

what happens in atrial fibrillation ?

Answer 392

-in atrial fibrillation , irregular waves of electrical excitation pass over the atria . -this causes the atria to contract randomly and rapidly up to several times per minute .

Question 393

is the electrical excitation transmitted to the ventricles ?

Answer 393

no , as you can see , the ventricles contract less frequently m than the atria . -as the normal rhythm of he heart is disrupted ,atrial fibrillation is a type of arrhythmia .

Question 394

how is atrial fibrillation treated ?

Answer 394

atrial fibrillation is treated with medication or surgery .

Question 395

GILLS CONTINUED

Answer 395

Many pairs of gill filaments extend from each gill arch . - gill filaments are covered with numerous gill lamellae which are also called gill plates . Hill lamellae are where gas exchange takes place .

Question 396

GILLS CONTINUED

Answer 396

Many pairs of gill filaments extend from each gill arch . - gill filaments are covered with numerous gill lamellae which are also called gill plates . Hill lamellae are where gas exchange takes place .

Question 397

Gas exchange lart four fish

Answer 397

Water flows between the fill lamellae , oxygen diffuses from the water , into the bloodstream . And carbodnxifoide diffuses from blood stream to waye d

Question 398

Gas exchange lart four fish

Answer 398

Water flows between the fill lamellae , oxygen diffuses from the water , into the bloodstream . And carbodnxifoide diffuses from blood stream to waye r

Question 399

Gill lamellae are adapted for efficient diffusion of gases - adaption 1

Answer 399

Firstly girll lamellae have a MASSIVE surface area for gases to diffuse over time.

Question 400

Gill lamellae are adapted for efficient diffusion of gases - adaption 1

Answer 400

Firstly girll lamellae have a MASSIVE surface area for gases to diffuse over time.

Question 401

Gill lamellae adaptation 2

Answer 401

There is a very short diffusion distance through the walls of the lamellae and blood stream.

Question 402

Gill lamellae adaptation 2

Answer 402

There is a very short diffusion distance through the walls of the lamellae and blood stream.

Question 403

Gill lamalelae adaption 3

Answer 403

They have an extensive network of blood capillaries .

Question 404

Gas exchange in fish part 5

Answer 404

Once oxygen diffuses into the blood it is carried away , and this maintains a steep conecnrtrarion gradient for oxygen

Question 405

Gas exchange in fish part 5

Answer 405

Once oxygen diffuses into the blood it is carried away , and this maintains a steep conecnrtrarion gradient for oxygen

Question 406

Another way thag bony fish are adapted for efficient diffusion of gas .

Answer 406

Counter current exchange system

Question 407

Another way thag bony fish are adapted for efficient diffusion of gas .

Answer 407

Counter current exchange system

Question 408

In order to understand counter current exchange system need to take a closer look at the full lamellae .

Answer 408

Blood with a LOW CONC of oxygen passes into the capillaries of the hill lamellae . - as blood passes through the full lamellae oxygen diffuses from the water into the blood .

Question 409

In order to understand counter current exchange system need to take a closer look at the full lamellae .

Answer 409

Blood with a LOW CONC of oxygen passes into the capillaries of the hill lamellae . - as blood passes through the full lamellae oxygen diffuses from the water into the blood .

Question 410

In order to understand counter current exchange system need to take a closer look at the full lamellae . Part two

Answer 410

Oxygen rich blood now passes out of the hill lamellae and leaves the gills . Key : the FLOW OF BLOOD is opposite direction to flow of water . / as the blood and water move in opposite directions this is called a counter current system . () blood uo n down and —-> water

Question 411

In order to understand counter current exchange system need to take a closer look at the full lamellae . Part two

Answer 411

Oxygen rich blood now passes out of the hill lamellae and leaves the gills . Key : the FLOW OF BLOOD is opposite direction to flow of water . / as the blood and water move in opposite directions this is called a counter current system . () blood uo n down and —-> water

Question 412

One major advantage of a counter current system

Answer 412

It always a maintains a steep conc gradient for oxygen .

Question 413

One major advantage of a counter current system

Answer 413

It always a maintains a steep conc gradient for oxygen .

Question 414

In fish , what would happen if blood and water flow in same direction !

Answer 414

Parallel flow Initially water has a much greater concentration than blood so high diffusion from water to blood teen . However , after a short distance the concentration of oxygen is the same on both blood and water , acid digs call fhis equilibrium at this point diffusion stops SO NO MORE THAN 50% of the available oxygen in the water can diffuse into the blood. .

Question 415

At HWOEBER if the blood flows in the opposite direction to water in case hony fish

Answer 415

There is ALWAYS A CONCNETRATION HRSIDEKT FOR OFYGEN SO EWUOLIBORUM IS NEVER EACHES AND DIFDUSION FAKES PLACE RIGHT ACROSS THE LENGTH OF LAMELLAE WITH a countercurrent flow up to around 80% of ofygen in water diffused into the blood stream .

Question 416

How bony fish maintain constant water flow through the gas exchange system ? 

Answer 416

In non bony fish like shark the flow of water theu the moth and over the gills is caused by fish swimming forward but bony fish evolved a different mechanical which allows water flow to occur even when fish is not swimming

Question 417

How bony fish maintain constant water flow through the gas exchange system ? (2)

Answer 417

Wheh a bony fish opens its mouth wayer flows into the mouth space , which is also called BUCCAL CAVITY - the floor of the bucks csviity drops down increasing the volume for available water

Question 418

How bony fish maintain constant water flow through the gas exchange system ? (2)

Answer 418

Wheh a bony fish opens its mouth wayer flows into the mouth space , which is also called BUCCAL CAVITY - the floor of the bucks csviity drops down increasing the volume for available water

Question 419

(3) How bony fish maintain constant water flow through the gas exchange system ?

Answer 419

The fish then shuts the operculum . And increase the volume of the operculuf cavity which contains the gills . - due to the increased volume the pressure in the opercular cavity falls , at the same time the floor of the buccal cavity lifts upwards . -

Question 420

(3) How bony fish maintain constant water flow through the gas exchange system ?

Answer 420

The fish then shuts the operculum . And increase the volume of the operculuf cavity which contains the gills . - due to the increased volume the pressure in the opercular cavity falls , at the same time the floor of the buccal cavity lifts upwards . -

Question 421

Part four, how old does bony fish take hold of water flow through the gas exchange system? ?

Answer 421

this increases the pressure of the water causing the water to flow over the gills ingot the opercular cavity , now the fish closes its mouth and opens its operculum . At the same time the sides of the opercular cavity squeeze inwards on the water , incresss the pressure of water , forcing it out of the operculum.

Question 422

Part four, how old does bony fish take hold of water flow through the gas exchange system? ?

Answer 422

this increases the pressure of the water causing the water to flow over the gills ingot the opercular cavity , now the fish closes its mouth and opens its operculum . At the same time the sides of the opercular cavity squeeze inwards on the water , incresss the pressure of water , forcing it out of the operculum.

Question 423

Now return back to insects !!!

Answer 423

Hehehe

Question 424

What is a spirometer

Answer 424

Lung volumes can be measured using a sprig meter , this is a device that measures the movmemenf of air in and out of the longs as a Perok breathes . During inspiration aid ks drawn from the chamber’s so lid moved down air returns to chambers raiding the lid during expiration . Co2 exhaled passing into soda like which absorbs co2 allowing the masient ox ox hehe consumption .

Question 425

What is a spirometer

Answer 425

Lung volumes can be measured using a sprig meter , this is a device that measures the movmemenf of air in and out of the longs as a Perok breathes . During inspiration aid ks drawn from the chamber’s so lid moved down air returns to chambers raiding the lid during expiration . Co2 exhaled passing into soda like which absorbs co2 allowing the masient ox ox hehe consumption .

Question 426

Precautions that must be taken when you get spirometer

Answer 426

The tablet should be healthy and in particular free from last month. The soda lime should be fresh and functioning. There should be no leaks in operator as invalid results. Should be sterilised. The water chamber must not be overfilled.

Question 427

Precautions that must be taken when you get spirometer

Answer 427

The tablet should be healthy and in particular free from last month. The soda lime should be fresh and functioning. There should be no leaks in operator as invalid results. Should be sterilised. The water chamber must not be overfilled.

Question 428

What does the total lung volume consist of?

Answer 428

The total log consist of the vert capacity, which can be measured at the residual volume, which cannot be measure uring the spirometer

Question 429

What is the vital capacity? Also check the graph.

Answer 429

What capacity is the maximum volume of air that could be moved by the long breath. This is taking deep breath and exploring all the possible belts. Capacity depends upon a number of factors such as The size of Bullet point agent gender. The level exercise capacity may rise and athletes usually for everyone it’s usually 2.5 to 5.0 decimetres cubed

Question 430

What is the vital capacity? Also check the graph.

Answer 430

What capacity is the maximum volume of air that could be moved by the long breath. This is taking deep breath and exploring all the possible belts. Capacity depends upon a number of factors such as The size of Bullet point agent gender. The level exercise capacity may rise and athletes usually for everyone it’s usually 2.5 to 5.0 decimetres cubed

Question 431

What is the residual volume?

Answer 431

The residual volume is the volume of air that remains in the lungs, even after forced expiration, the air remains in the airways of this approximately 1.5 dm cubed

Question 432

What is the residual volume?

Answer 432

The residual volume is the volume of air that remains in the lungs, even after forced expiration, the air remains in the airways of this approximately 1.5 dm cubed

Question 433

What is the tidal volume

Answer 433

The title volume is the volume of moved in and out with each breath. It is normally the rest. A typical heart of water is 0.5 decimated cubed. This is usually sufficient display all the required body arrest. Check the graph.

Question 434

Oxygen uptake

Answer 434

Breathing supplies alternative for respiration remove carbon oxide respiration. – as a person bruised from the spiral of oxygen is absorbed by the blood replaced by the crocodile. – This spiral so the volume of the decreases. Decrease can be observed and measured to trace. We can assume that the volume of carbon dioxide at least and absorbed by the total line equals the volume of ocean absorbed by the blood. Therefore, the grade of the decrease of volume enables us to calculate the road ox optic. Road Oxy optic..

Question 435

Oxygen uptake

Answer 435

Breathing supplies alternative for respiration remove carbon oxide respiration. – as a person bruised from the spiral of oxygen is absorbed by the blood replaced by the crocodile. – This spiral so the volume of the decreases. Decrease can be observed and measured to trace. We can assume that the volume of carbon dioxide at least and absorbed by the total line equals the volume of ocean absorbed by the blood. Therefore, the grade of the decrease of volume enables us to calculate the road ox optic. Road Oxy optic..

Question 436

Calculating oxygen uptake from a spirometer trace chrck sheet

Answer 436

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Question 437

Calculating oxygen uptake from a spirometer trace chrck sheet

Answer 437

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Question 438

Breathing rate

Answer 438

The breathing rate can also be measured by a spirometer trace, possibly cure a number of peaks in each minute, so it’s usually 12 to 14 breaths per minute at rest

Question 439

Breathing rate

Answer 439

The breathing rate can also be measured by a spirometer trace, possibly cure a number of peaks in each minute, so it’s usually 12 to 14 breaths per minute at rest

Question 440

Oxygen uptake

Answer 440

So Oxid table depend on the number of factors are higher oxide. Obtainable result from increase, such as during exercise when the muscles are spiral. Increase result from increased breathing rate and deeper breaths.

Question 441

Oxygen uptake

Answer 441

So Oxid table depend on the number of factors are higher oxide. Obtainable result from increase, such as during exercise when the muscles are spiral. Increase result from increased breathing rate and deeper breaths.