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A level Biology - Regular > Chapter 8 - Transport in animals > Flashcards

Chapter 8 - Transport in animals Flashcards

1
Q

Why do animals need specialised transport systems ?

A
  • High metabolic demand
  • Small SA:V ratio as multicellular organisms size increases hence diffusion distance increases
  • Waste products need to be removed from cells
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2
Q

What are the common features of animals specialised circulatory systems ?

A
  • Liquid transport medium around the body
  • Vessels that carry transport medium
  • Pumping mechanism to move fluid around
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3
Q

What are the 2 types of circulatory systems ?

A

1 - Open circulatory system
2 - Closed circulatory system

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4
Q

What are the features of open circulatory systems ?
(in insects)

A
  • very few vessels to contain transport medium (haemolymph)
  • pumped straight from the heart to the body cavity (Haemocoel)
  • medium is under low pressure in Haemocoel and comes into direct contact with tissues and cells for gas exchange
  • medium returns to heart in open ended vessel
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5
Q

What are the features of the structure of insecrs circulatory systems ?

A
  • Body cavity is split by a membrane
  • Heart extends along the thorax and abdomen of the insect
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6
Q

What are the two types of closed circulatory systems ?

A

1 - Single closed
2 - Double circulatory

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7
Q

What are the overall features of a closed circulatory system ?

A
  • Blood is enclosed in vessels; does not come into direct contact with the cells of the body
  • Heart pumps blood around body under pressure and quickly then blood returns directly to the heart
  • Amount of blood flowing to a particular tissue can be adjusted by widening or narrowing vessels
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8
Q

How does a single closed circulatory system look like ?

A
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9
Q

What are the features of single closed circulatory systems ?

A
  • Blood flows through heart and is pumped out to travel all around the body before returning to the heart
  • Travels through 2 sets of capillaries before returning to the heart
  • In the 1st set of capillaries O2 and CO2 are exhanged
  • In the 2nd substances are exchanged between blood and cells = Drop in B.P
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9
Q

What are the features of single closed circulatory systems ?

A
  • Blood flows through heart and is pu,ped out to travel all around the body before returning to the heart
  • Travels through 2 sets of capillaries before returning to the heart
  • In the 1st set of capillaries O2 and CO2 are exhanged
  • In the 2nd substances are exchanged between blood and cells = Drop in B.P
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10
Q

Why is a single closed circulatory system inefficient ?

A

Passing through two sets of narrow capillaries means b.p. drops
This leads to blood returning to the heart slowly
Hence gas exchange cannot occur quickly enough
Hence animals with this tend to be less active = lower metabolic demand

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11
Q

What are the advantages of double circulatory systems ?

A

Allows an organism to maintain their body temperature

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12
Q

What are the features of a double circulatory system ?

A
  • Blood is pumped from heart to lungs to pick up oxygen and unload CO2 and then returns to heart
  • Blood flows through heart and is pumped around the body before returning to the heart
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13
Q

What are the 3 components utilised in blood vessels ?

A

1 - Elastic fibres
2 - Smooth muscle
3 - Collagen

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14
Q

What are the features of Elastic fibres ?

A
  • Comprised of elastin and recoil, providing vessel walls with flexibility
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15
Q

What are the features of smooth muscles ?

A
  • Contracts or relaxes, which changes size of the lumen
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16
Q

What are the features of collagen ?

A
  • Provides structural support to maintain the shape and volume of the vessel
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17
Q

What are the features of arteries ?

A
  • Carry oxygenated blood away from the heart except in the pulmonary artery which carries deoxygenated blood from heart to lungs
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18
Q

What are the features of umbillical arteries ?

A

Carry deoxygenated blood from the fetus to the placenta

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19
Q

What are the structural adaptations of the arteries ?

A

Artery walls contian all three structures, elastic fibres, smooth muscles and collagen.

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20
Q

How is the presence of elastic fibres an adaptaion in arteries ?

A
  • Elastic fibres enable them to withstand the force of the blood pumped out of the heart and stretch
  • Elastic fibres cause recoiling of the vessels and return back to their normal shape
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21
Q

How is the presence of smooth muscle an adaptation in arteries ?

A
  • Smooth endothelium so blood can flow easily
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22
Q

What are arteroiles ?
What is their composition ?

A

Vessels that link arteries and the capillaries
More smooth muscle, less elastin than arteries

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23
Q

What is the function of arterioles ?

A
  • Can constrict or dilate to control flow of blood into individual organs.

Smooth muscle contract = Arterioles constrict

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24
Q

What are arterioles ?

A

Microscopic blood vessels that link arterioles with venules

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25
Q

How are substances exchanged in capillaries ?

A
  • Exhange through capillary walls between tissue cells and blood inside the capillaries
  • Substances pass thorugh the gaps between endothelial cells
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26
Q

What are the adaptations of capillaries ?

A

1) Small lumen so blood vessels travel in single file
2) Large SA:V ratio for diffusion of substances
3) Total cross sectional area of capillaries is greater than arteroile that supplies it with blood hence b.p decreases hence blood flow decreases hence more time to exchange materials
4) Walls are single endothelial cells thick hence thin layer for diffusion

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27
Q

What are the functions of veins and what are the exceptions ?

A

Carry deoxygenated blood away from cells of the body towards the heart
2 exceptions :
1. Pulmonary vein - carries oxygenated blood from lungs to heart
2. umbillical vein - carries oxygenated blood from placenta to fetus

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28
Q

How does blood flow into the veins ?

A

Deoxygenated blood flows from capillaries into very small veins called venules and then into larger veins.
Finally it reaches two main vessels, inferior vena cava and superior vena cava

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29
Q

Why are there no surges from the heart pumping in the veins ?

A

The surges from the heart pumping are lost as the blood passes through narrow capillaries

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30
Q

What are the structural features of veins ?

A
  • Lots of collagen
  • Little elastic fibre
  • Wide lumen and thin endothelium lining
    henc blood flows easily
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31
Q

What is the function of a venule ?
What are its structural features ?

A
  • Link capillaries with the veins
  • Thin walls with little smooth muscle
  • Many venules join to form veins
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32
Q

What are the adaptations of veins ?

A
  1. One way valves at intervals, If blood flows backwards the valves will close to prevent this from happening
  2. Big veins run lie between large active muscles. When the muscles contract they put pressure on the veins thereby forcing blood towards the heart
  3. Breathing movements of the chest act as a pump. The pressure changes and the squeexing actions move blood in the veins of the chest and abdomen to the heart
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33
Q

What does blood mainly consist of ?

A

Plasma

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34
Q

What does plasma carry ?

A
  • Glucose
  • Ions
  • Hormones
  • Albumin
  • Fibrinogen
  • Globulins
  • Red blood cells
  • White blood cells
  • Platelets
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35
Q

What are platelets ?
What is their function ?

A

Fragments of large cells found in bone marrow
Involved in clotting mechanisms of the blood

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36
Q

What are the functions of the blood ?

A

Transport of :
- O2 to and CO2 from respiring cells
- Digested food from small intensitines
- Nitrogenous waste products from cells to excretory organs
- Hormones to act as chemical messengers
- Food molecules from storage compounds to cells that need them
- Platelets to damaged areas
- Cells and antibodies

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37
Q

What is osmotic effect ?

A

When blood in capillaries have a high solute concentrations therefore water diffuses into the blood vua osmosis

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38
Q

What leads to a high osmotic effect in capillaries ?

A
  • substances in plasma can pass through holes (fenestrations) in capillary walls except albumin
  • Precense of albumin causes an increased solute conc.
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39
Q

What is the definition of oncotic pressure ?

A
  • Tendency of water to move into the blood via osmosis
40
Q

Why is fluid still moved out of the capillaries if there is a high oncotic pressure ?

A

As blood flows from the arterioles into capillaries it is under pressure from the surge of blood that occurs every time the heart contracts - Hydrostatic pressure which is higher than oncotic pressure - hence forcing fluid out

41
Q

Where does the fluid coming out of the capillaries diffuse into ?

A

Fills spaces between cells and is called tissue fluid

42
Q

What does tissue fluid contain ?

A
  • Same composition as plasma minus RBC and plasma proteins
43
Q

What medium does the diffusion of O2 and CO2 between cells and capillaries occur in ?

A

Through the tissue fluid

44
Q

How does pressure change moving from capillary to venous end ?

A

Hydrostatic pressure falls - as fluid has been moved out. Oncotic pressure remains the same

Hence oncotic pressure is stronger than hydrostatic pressure - water moves back into the capillaries via osmosis as it approaches the venous end

45
Q

What is Lymph ?

A

When 10% of the liquid that leaves the blood vessels drains into a system of blind-ended tubes known as lymph capillaries

46
Q

What is the composition of Lymph ?

A

Similar to plasma with less oxygen and fewer nutrients and contains fatty acids

47
Q

How do lymph capillaries work ?

A

join up to form larger vessels and fluid is transported through them by squeezing of the body muscles

48
Q

What is an adaptation of lymph capillaries ?

A

One way valves like veins to prevent backflow of lymph

49
Q

What are the functions of lymph nodes ?

A

Store Lymphocytes
Intercept bacteria and debris from the lymph

50
Q

What occurs at the lymph nodes ?

A
  1. Lymphocytes produce antibodies and secrete them when necessary
  2. Phaggocyted ingest the built up bacteria
51
Q

What are swolen lymph nodes a sign of ?

A
  • Body is fighting off invading pathogens
52
Q

What is the main function of an Erythrocyte ?

A

Transport Oxygen to the cells that need it

53
Q

What are the main adaptations of Erythrocytes ?

A
  1. Biconcave shape - this shape has a larger SA:V ratio hence diffusion of gases occurs faster
  2. Small size - Helpsthem to pass through capillaries
  3. No nucelei - maximises the amount of Haemoglobin that fits into the cells
54
Q

What allows Erythrocytes to carry Oxygen ?

A

Haemoglobin
- Conjugates protein made up of four peptide chains, wach with a Haem prosthetic group

55
Q

What is the equation for the reaction between Oxygen and Haemoglobin ?
What is Positive cooperativity ?

A

Positive cooperativity is when one oxygen molecule binds to Haemoglobin the prosthetic group changes shape; making it easier for the other oxygen molecules to bind

56
Q

How does Oxygen flow into the blood from the capillaries ?

A
  1. As Erythrocytes enter the capillaries in the lings, O2 conc. in the RBC are low hence there is a steep conc. gradient
  2. Oxygen moves into the Erythrocytes and binds with the haemoglobin
  3. As Oxygen is bound to the Haemoglobin the free oxygen concentration in the Erythrocyte stays low, so a steep conc. gradient is maintained until all the Harmoglobin is saturated
57
Q

How is the process different when blood flows into body tissues ?

A

Situation is reversed
- Conc. of O2 in cytoplasm of the body cells is lower than the Erythrocytes
- Oxygen moves out of the erythrocytes down a conc. gradient

58
Q

What does a dissociation curve show ?

A
  • Percentage saturation of haemoglonin against partial pressure of oxygen
  • Shows the affinity of haemoglobin for oxygen
59
Q

Why do small changes in partial pressures of oxygen cause large changes to the saturation of the haemoglobin ?

A
  • Once the first molecule becomes attached,the change in the shape of haemoglobin is saturated and cannot take up any more
60
Q

Describe a dissociation curve

A
61
Q

What is the Bohr effect ?

A

When the partial pressure of CO2 rises haemoglobin gives up oxygen more easily

62
Q

What are the results of the Bohr effect ?

A
  • In active tissues with high partial pressures of CO2, Haemoglobin gives up its O2 more easily
  • In the lungs, where partial pressures of CO2 are low, oxygen binds to the haemoglobin molecules easily
63
Q

What is fetal haemoglobin ?
Why is it necessary ?

A

Fetal Haemoglobin is the Haemoglobin present for fetus’. It has a higher affinity for oxygen

This is necessary as if the affinity were the same between fetal haemoglobin and regular haemoglobin. The fetus will not be able to deffuse into it any Oxygen

64
Q

What are the 3 ways in which Carbon dioxide are transported from tissues to lungs ?

A
  • 5% is carried dissolved in plasma
  • 10-20% is combined with amino groups in polypeptide chains of haemoglobi to form carbaaminohaemoglobin
  • 75-85% converted into hydrogen carbonate ions in cytoplasm of the RBC
65
Q

How are hydrogen carbonate ions made in the RBC ?

A
66
Q

What enzyme catalyses the reaction from carbon dioxide into hydrogen carbonate ions ?

A

Carbonic anydrase

67
Q

What is chloride shift ?

A

Negatively charged hydrogen carbonate ions move out of erythrocytes into the plasma by diffusion down a conc. gradient and negatively charged chloride ions move into the erythrocytes - maintaining electrical balance

68
Q

What occurs with hydrogen carbonate when the blood reaches the lungs ?

A
  • There is a relatively low conc. of Carbon dioxide in the lungs
  • Carbonic anhydrous catalyses the reverse reaction; breaking down Carbonic acid into CO2 and H2O
  • CO2 will then diffuse into the lungs and chloride ions will diffuse out of the RBC back into the plasma down an electrochemical gradient
69
Q

What is the purposs of Haemoglobin when CO2 moves out of the RBC ?

A

Acts as a buffer to prevent changes in the pG by accepting free Hydrogen ions to form Haemoglobinic acid

70
Q

What is the basic purpose of the heart ?

A
  • Deoxygenated blood from the body flows to the right side of the heart
  • Which pumps the blood to the lungs
  • Oxygenated blood from the lungs returns to the left side of the heart
  • Which pumps blood to the body
71
Q

What is the structure of the heart ?

A
72
Q

What is the dissected structure of the heart ?

A
73
Q

How does blood enter the heart ?

A

From the top of the body via the superior vena cava and the bottom of the body via the inferior vena cava. The blood enters at low pressures.

74
Q

How does blood travel into the right ventricle ?

A
  • Enters via vena cavas
  • Pressure builds up until the tricuspid valve opens and lets blood enter pass into right ventricle
  • When both atrium and ventricle are filled up atrium contracts; forcing all the blood into the right ventricle
  • As the tricuspid valve contracts the tricuspud valve closes again
75
Q

What is the purpose of the tendious cords ?

A

Make sure valves are not turned inside out by pressures exterted when the ventricle contracts

76
Q

How does deoxygenated blood enter the lungs ?

A
  • Right ventricle contracts fully
  • This pumps deoxygenated blood through the semilunar valves into the pulmonary arteries
  • The blood travels to the lungs in the pulmonary arteries
77
Q

How does oxygenated blood enter the heart ?

A
  • Enters the left atrium from pulmonary vein
  • As pressure in the atrium builds up valves open
  • Blood enters the left ventricle
  • When both atrium and ventricle are filled up the atrium will contract aand will force all the blood into the ventricle
  • Ventricle then contracts and pumps blood through semi-lunar valves into aorta around the body
78
Q

What are the adaptations of the heart ?

A
  1. Muscular wall of the left side of the heart is much thicker than that of the tight - The left ventricle transports blood to the whole body hence more resistance of pulmonary circulation
  2. Septum that divides the heart which prevents micing of deoxygenated and oxygenated blood
  3. Valves are unidirectional
  4. Made up of cardiac muscle
79
Q

What does a caridac cycle show ?

A
  • Describes the events in a single heartbeat
80
Q

What occurs in a diastole ?

A
  • Heart relaxes
  • Atria and then ventricles fill with blood
  • Volume and pressure of the blood in the heart build as the heart fills, but the pressure in the arteries is at a minimum
81
Q

What occurs in a systole ?

A
  • Atria contract
  • Follows by ventricles contracting
  • Pressure inside the heart increases dramatically and blood is forced out of the right sideof the heart to lungs and left side from heart to body
  • Volume and pressure of the blood at the end are low
82
Q

How does a caridac cycle look like ?

A
83
Q

What causes a heartbeat ?

A
  • Blood pressure closing the heart valves
84
Q

What is a lub-dub and how does it arise ?

A
  • Two sounds of a heartbeat
  • First sound comes as the blood is forced against the atrio-ventricular valve
  • Second sound comes as a backflow causing valves to close
85
Q

What is Myogenic ?

A

Cardiac muscle
- Has its own intrisinic rhythm

86
Q

What is the first step to maintaining a heartbeat ?

A
  1. Wave of electrical exitation occurs in teh pacemaker known as sin-atrial node; causing the atria to contract and initiates the heartbeat
87
Q

What is the second step to maintaining a heartbeat ?

A
  1. Electrical activity from SAN picks up by atrio ventricular node which stimulates bundle of His (conducting tissue known as Purkyne fibres) which penetrates through septum
88
Q

What is the third step to maintaining a heart beat ?

A
  1. Bundle of His is split into two branches and conducts wave of excitration to the apex which is the bottom of the heart
89
Q

What is the fourth step to maintaining a heart beat ?

A
  1. At the apex the Purkyne fibres spread out through the walls of the ventricles on both sides this spread of excitation triggers the contraction of ventricles, starting at the apex; maing the emptying of ventricles more efficient
90
Q

What is the reason for the delay between the excitation spread from SAN and AVN delay ?

A
  • Makes sure that atria have stopped contracting before ventricles start
91
Q

What are electrodiagrams used for ?

A
  • Used to measure the spread of electrical excitation through the heart as a way of recording what happens as it contracts
92
Q

What are the 4 commonly shown heatt rhythym abnormalities ?

A
  1. Tachycardia
  2. Bradycardia
  3. Ectopoc heartbeat
  4. Atrial fibrillation arrhthymia
93
Q

How does a normal ECG look like ?

A
94
Q

What are the features of Tachycardia ?
What does its ECG graph look like ?

A
  • Rapid heartbeat which is over 100bpm
  • Relates to exercise or fever
95
Q

What are the features of Bradycardia ?
What does its ECG graph look like ?

A
  • Heart rate slows down to below 60bpm
  • Related to fitness
96
Q

What are the features of Ectopic heartbeat ?
What does its RCG graph look like ?

A
  • Extra heartbeats that are out of rythym
97
Q

What are the features of Atrial fibrillation ?
What does its ECG graph look like ?

A
  • Example of Arrythmia
  • Abnormal rythym with rapid electrical impulses generated in the atria

A level Biology - Regular (14 decks)

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