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alevel bio > Chapter 8; Circulatory System > Flashcards

Chapter 8; Circulatory System Flashcards

1
Q

Why do large organisms need a circulatory system

A

-large diffusion distance
-bc made up of many layers of cells
-so takes too much time to gain reactants of metabolism

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2
Q

Explain what the human circulatory system is

A

Closed and double
-closed bc blood is contained within a network of blood vessels
-doub le bc passes throuhg the heart twice

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3
Q

What is an open circulatory system

A

Blood is pumped directly into tissues,
So is not contained within vessels

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4
Q

Difference between systemic and pulmonary circulatory system

A

Systemic ciruvclation allows for blood to be pumped around the body at high pressures,
(High pressures are produced from the left ventricle bc there is more muscle here so it can produce stronger muscle contractions than the right. )
-so this ensures blood reaches every part of the body quickly and efficiently

Pulmonary pumps blood at much lower pressures got ensure no damage to capillaires

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5
Q

Explain the difference between elastic arteries and muscular arteries and state which ones are closer to the heart

A

-elastic arteries are closer to the heart than muscular arteries are

-elastic arteries have a thicker tunica media, and more elastic fibres present in it.
-this is to stretch and recoil to withstand high pressures and so prevent likelihood of bursting
-and also to keep blood flowing, so in line with pulsating flow of blood

-muscular arteries have a thinner tunica media
-have more muscular tissue than elastic
-can constitute the diameter of the artery and so control volume of blood flow, and this also lets to maintain pressure

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6
Q

State the components and functions of the tunica media in an artery

A

Elastic fibres,
-stretch and recoil to withstand pressures and so reduces the likelihood of bursting
-keeps blood moving so in line with the pulsating flow of blood

Muscle fibres,
-maintain blood pressure,
-and constrict diameter of the artery so control volume of blood flow to different tissues

Collagen fibres,
-withstands high pressures and prevents rupture of blood vessels

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7
Q

Describe the tunica intima/ endothelium of an artery

A

Tunica intima is folded

-made up of squamous epithelial cells,(flattened and one cell thick)
-so smooth surface which reduces friction so less damage to cells in the artery

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8
Q

What is the tunica externa in an artery made up of

A

Elastic fibres and collagen fibres

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9
Q

Explain 4 features and their functions in an artery

A

-narrow lumen, to maintain high blood pressures
-thick wall to withstand high pressures
-elastic fibres to stretch and recoil and so withstand high pressures and so prevent bursting
-muscle fibres to maintain high pressures and to construct diameter of artery, controls how much blood flows

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10
Q

Give 4 differences between arteries and veins

A

-arteries have a folded endothelium, but veins have a straight endothelium
-arteries have a narrow lumen in relation to walls thickness but veins have a wide lumen in relation to wall thickness
-arteries have a thick tunica media, veins have a thin tunica media
-arteries have a well defined oval shape, veins have an irregular flattened oval shape

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11
Q

Otherwise than the lumen and walls of veins, give two otehr features and their functions in veins

A

Skeletal muscles, which contract to push blood towards the heart
Valves, which prevent the back flow of blood

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12
Q

Which components in veins are responsible for the low pressures in them

A

-distance away from the heart
-tissue fluid formation bc the blood loses substances
-bc blood passes through capillaires before this, where blood flow is already slowed down

(Never ask about muscular fires or elastic tissue in terms of pressure in the veins bc pressure is negligible in veins)

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13
Q

Give three adaptions of a capillary and their functions

A

-one cell thick, so reduced diffusion distance between capillary and neighboring cells
-has fenstrations, which allows small components of blood such as water, ions, glucose to pass through and form tissue fluid
-small lumen diameter, so red blood cells are in contact with the capillary wall, so this increases resistance, so slows down flow of blood, so better exchange of substances, and also reduces pressure
(The small lumen diameter also reduces diffusion distance)

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14
Q

Explain the difference between an arteirole and an artery and why this is important

A

-arterioles are smaller than arteries to produce resistance and therfore slow down the pressure of blood bc slower blood flow is better of exchange of substances once it enters into the capillaries

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15
Q

Explain the formation of tissue fluid

A

-high hdyiortstic pressure at the arterial end, bc coming form the left ventricle of the heart
-hydroststic pressure in capillary is greater than the fluid surrounding it

-although capillaries also have high ocnotic pressure, due to many protiens dissolved in it which all of do not pass into issue fluid(so u would assume that water would move into the capillaries via osmosis)

-hydrostatic pressure>on optic pressure

-so blood plasma is forced out of the capillary through fnestrations and becomes tissue fluid.
(Water, glucose, amino acids, some white blood cells, some protiens, carbon dioxide and oxygen)

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16
Q

State the substances present in tissue fluid

A

Water
Glucose
Amino acids
Some white blood cells
Some proteins
Carbon dioxide
Oxygen

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17
Q

Explain the return of tissue fluid back to the blood

A

Lower hydrtatic pressure at the venue end of capillary
(Bc blood is at lower pressure,
and also because capillaires have lower water potential bc large amount of fluid has been lost previously to the tissue fluid, therfore large amount of solutes dissolved in it)

Also high ocncoitc pressure in capillary due to many protiens and cells left in capillary,

So ocnotic pressure more than hdyortstic pressure, so overall net movement of water out of tissue fluid into capillary via osmosis

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18
Q

How is lymph formed, and then how is it returned back tot he blood

A

Most tissue fluid reenters into capillaries,
But some excess fluid consisting of water materials is drained into lymph capillaries

Eventually renters blood through veins close to the heart(so any plasma protiens previously escaped form the blood can be returned again)

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19
Q

Estate 4 features of lymph capillaries

A

Contain lymph nodes, so filter out bacteria using lymphocytes
Skeletal muscle, to cause movement of blood
Valves, to prevent backflow of blood
Large pores to allow large meocluels to pass through

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20
Q

Centruged blood consists of three main sections. State what these are from most abundant to least abundant

A

Plasma
Red blood cells
Platelets and white blood cells

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21
Q

Give two functions of tissue fluid

A

-bathes cells to enable exchange of substances between the blood
-maintains homeostasis

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22
Q

Give 7 components of blood plasma and state one thing that it does not have

A

-water
Ions
Nurtrients (amino acids and glucose)
Urea
Carbon dioxide
Water
Protiens

BUT HAS NO CELLS

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23
Q

Explain the strutcure of haemoglobin

A

Globular strutcure,(compact and roughly spherical and soluble in water bc of hydrophilic r groups)
Quarternary sturtcure, (2 alpha globulin chains and 2 beta globin chains)
Cosnmisst of 4 prosthetic haem groups, each with an iron 2 plus in them. (S each haem group can bind to one oxygen molecule, so in total haemoglobin carries 8 oxygen atoms)

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24
Q

Give three features and adaptions of red blood cells

A

-small and flexible, so able to deform, and squeeze through capillaries which reduces diffusion distance
-no nucleus, mitochondria or er, to maximize haemoglobin and so amount of oxygen carried
-bioconcave disk, to increase surface area for disunion of oxygen to cells

25
Q

Give three differences between red blood cells and white blood cells

A

-white blood cells larger than red blood cells, (excpet form lymphocytes which are smaller than red blood cells)
-white blood cells have a nucleus but red blood cells do not
-white blood cells have a spherical irregular shape but red blood cells have a bioconcave disk shape

26
Q

Differences and similarities between neutrophils and monocytes

A

Neutrophils are short lived, monocytes are long lived
Neutrophils have a multilobed nucleus, monocytes have a lobed nucleus

-both have repcoter proteins on surface
-both have granular cytoplasm

27
Q

Explain the sturtcure of a lymphocyte

A

-Large round nucleus that takes up most of cytoplasm of a cell
-smaller than phagocytes

28
Q

For the different phagocytes and for erythrocytes, state in ascending order of size form smallest to biggest

A

Lymphocytes
Erythrocytes
Neutrophils
Monocytes
Macrophage (matured monocyte)

29
Q

What is cardiac output and how can this be increased

A

Volume of blood pumped per minute

-can be increased by decreasing aortic pressure(bc it will then do the opposite to counteract this)
-increasing carbon dioxide leevels

30
Q

Difference between semi lunar valves and atriovenriuvlar valves,
And then give examples of semi lunar valves

A

Semi lunar valves are between the ventricles and arteries
(There is the aortic valve and the pulmonary valve)
Atrioventricular valves are between the ventricles and the atria

31
Q

Function of ther septum in the heart

A

Separates oxygenated and oxygenated blood

32
Q

What is oedema (hyper tension) and how does this occur

A

When hydrostatic pressure is too high at the arterial end and so
-pushes too much fluid out of the capillary
-which accumulates around the tissue and so causes swelling

33
Q

Explain how the structure of the ventricles differs from the structure of the atria and explain how this is

A

Ventricles are thicker and more muscular than the atria
-therfore when they contract they generate much more pressure than the atria
-so blood can reach other organs efficiently

34
Q

Explain how left ventricle differs form the right and state why this is

A

Left ventricle thicker than left
To generate more pressure
Because needs to be pumped to the rest of the body

35
Q

What are the papillary muscles, where are they found ad what are their role

A

Found in left ventricles
Role is to prevent the inversion of valves during ventricular siastole

36
Q

What is the role of the tendon

A

Prevent atrioventirucvalr valves from turning inside out and so help maintain the unidirectional flow of the heart

37
Q

Role of the coronary arteries

A

Supply cardiac muscles with nutrients and remove waste products

38
Q

Why should coronary arteries remain clear of plaque

A

Bc if blocked
Less oxygen to heart muscle cells
S less respiration
So less atp produced
So less contract of heart muscle
So less oxygen to other body cells
And so this can lead to fatigue

39
Q

Explain what happens in diastole

A

Blood simultaneously begins to enter both atrial throuhg the pulmonary vein and vena cava
Pressure in the aorta and pulmonary artery is more than the pressure in the ventricles, so the semi lunar valves close
Pressure in the atria is more than in the ventricles, so the AV valves open,(so blood flows passively in the ventricles)

40
Q

Explain what happens in atrial siastole

A

Atrial walls contract so the pressure in the atria is more than that in the ventricles.
So the AV valves open
And remaining blood is forced into the ventricles
The semi lunar valves remain closed.

41
Q

Explain what happens in ventricular siastole

A

-ventricles contract and pressure in ventricles is more than in the aorta and pulmonary artery so semi lunar valves open.
-pressure in the ventricles is more than in the atria, so the av valves close to prevent the backflow of blood

42
Q

What causes the ‘lug dub’ sound during the cardiac cycle

A

When the av valves close in ventricular siastole and when the semi lunar valves close in diastole

43
Q

Explain the process of how heartbeat is initiated and controlled

A

-the SAN initiates a wave of depolarization (a wave of excitement)
-this wave of excitement causes both the atria to contract through atrial siastole
-atria and ventricles are separated by a layer of non conducting tissue which prevents the depolaristaion from travelling straight down to the ventricles
-instead it travels to the avn
-after a short delay the avn is stimulated and passes the simulation along down the bundle of his
(Short delay occurs so that the ventricles contract after the atria,so gives ventricles time to fill up with blood)
-bundle of his divides into purkeyne fibres which carry the wave of excitation along them into the muscle in the ventricles walls
-this indicators the depolarization of the ventricles, causing therm to contract so contract from the apex upwards

44
Q

What is the SAN and where in the heart is it located

A

It is the pace maker of the heart so sets the heart beat of the heart. It is a group of cells located in the wall of the right atrium

45
Q

What is meant by the heart being myogenic

A

It can beat without external stimuli so by itself

46
Q

Explain the chloride shift

A

Carbon dioxide diffuses into red blood cells
Carbon dioxide combines with water to form carbonic acid, which by using the Carbonic anhydrase enzyme forms carbonic acid
Carbonic acid dissociates into into h plus ions and hydrogen carbonate ions
Hydrogen carbonate Ions are transported out of the cell into the plasma through a transport protein.
Negatively charged chloride ions are transported in throuhg the same transport protein
(This is done to prevent an electrical imbalance so that there is not a build up of h plus ions in the red blood cell.)

47
Q

How is haemoglobinic acid formed and explain why this is beneficial

A

When h plus ions combine with haemoglobin it is formed.
It acts as a buffer so prevents the ph of the blood from decreasing (bc it does not change the ph of the blood)

48
Q

Explain how oxygen is released form a red blood cell due to the presence of carbon dioxide

A

Carbon dioxide diffuses into the red blood cell
Combines with water to form carbonic acid catalyses by carbonic anydhrase
This dissociates into h plus ions and hydrogen carbonate
H plus ions combine with haemoglobin to form haemoglobin c acid

H plus ions have a higher affinity for haemoglobin than oxygen does.
So they therfore lower the affinity of haemoglobin for oxygen
So oxygen is released more readily

49
Q

which two substances can lower haemoglobin affinity for oxygen and explain how

A

CO2, bc production of carbonic acid which dissociates into h plus ions.
Where h plus ions combine w haemoglobin to produce haemoglobin acid
And bc haemoglobin has higher affinity for h plus ions than for oxygen oxygen is released more readily

Carbon monoxide
Which combine with haemoglobin to form carboxyhaemkglobin
Haemoglobin has higher affinity for carbon monoxide than it does does for oxygen
So oxygen is therfore relaxed

50
Q

explain how,
Carbonic acid
Carboxyhameoglobin
Haemoglobin acid
Carbaminohaemoglobin

Are all formed

A

-co2 plus water in the red blood cell
-co binds to haemoglobin
-h plus ions bind to haemoglobin
-carbon dioxide binds directly to haemoglobin

51
Q

give 4 pathways that co2 in the blood can take

A

-can diffuse into red blood cells and with water form carbonic acid
-can bind directly to haemoglobin and form carbaminohaemoglobin
- can dissolve dorvekty into blood plasma
- can dissociate into hco3 ions in the blood plasma, by combining with water

52
Q

explain why less hco3 ions in blood plasma than in red blood cells

A

-less carbonic anyhdarse in blood plasma
So less formation of carbonic acid
so less dissociation into hco3 ions

53
Q

One feature that the trachea and bronchus have but the bronchiole does not

A

Cartilage

54
Q

Explain the difference between the cartilage in the trachea and in the bronchus

A

In the trachea it is C shaped.
In the bronchus it is not,

In the trachea its function is to support the trachea and keep it open whilst breathing
But in the bronchus, its role it to prevent it form collapsing

55
Q

State three components of the ciloated epithelium and their functions

A

Cilia cells- beat to move musics away for, the lungs and up towards the mouth

Goblet cells-produce mucus to trap dust, bacteria and other microorganisms, preventing them from reaching the lungs

Mucous glands-produce mucus to trap bacteria and dirt

56
Q

Function of elastic fibres in the gas exchange system and function of smooth muscle in gas exchange system

A

Elastic fibres,
Stretch for inspiration
Recoil for expeirtaion

Smooth muscle
Relax when more air is needed
Constrict when less air is needed

57
Q

Desicribe the squamous epithelium and explain its function

A

Thin and flat.
Permeable so allow for diffusion of gases
Short so short diffusion distance

58
Q

Give three components of the alveoli

A

Alveolar space
Alveolar duct
Squamous epithelium

59
Q

Explain what could happen if the elastic fibers in the alveoli are damaged

A

Aleveoli can no longer stretch
So they burst
And so less recoil and so less air out

alevel bio (11 decks)

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