heart 2

Question 1

Describe co-operative binding

Answer 1

1- After the first oxygen binds, the second one binds easier.

2- The first oxygen binding changes the quaternary structure of the haemoglobin, so it changes shape.

3- This uncovers another haem binding site for the second oxygen to bind to.

Question 2

Describe and explain the level and type of protein comprising haemoglobin

Answer 2

Globular (specific shape for binding). Quaternary. 4 polypeptide chains, and 4 haem binding groups.

Question 3

Describe and explain the process of oxygen loading to haemoglobin

Answer 3

Occurs in lungs

where p(O2) is high

Haemoglobin has a high affinity for oxygen.

Oxygen will load/associate with haemoglobin more readily, forming oxyhaemoglobin.

Question 4

Describe and explain the process of oxygen unloading from haemoglobin

Answer 4

Occurs at respiring tissues

where p(O2) is low

As oxygen is required by respiring tissues for aerobic respiration, to release energy.

Haemoglobin has a low affinity for oxygen.

Oxygen will unload/dissociate with haemoglobin more readily.

Unloading is linked to a high concentration of carbon dioxide - Bohr effect.

Question 5

Describe the red curve

Answer 5

Foetal haemoglobin.

Oxygen transferred to foetus from mother at placenta.

Haemoglobin has a higher affinity for oxygen.

Oxygen will load/associate more readily with haemoglobin.

Question 6

Describe the blue curve

Answer 6

Haemoglobin for a smaller mammal.

Haemoglobin has a lower affinity for oxygen.

Oxygen unloads/dissociates more readily

supply respiring tissues with more oxygen for increased rate of aerobic respiration to release more energy.

Question 7

Blood vessel taking blood into left atrium

Answer 7

Pulmonary vein

Question 8

Blood vessel taking blood into right atrium

Answer 8

Vena cava

Question 9

Blood vessel taking blood out of left ventricle

Answer 9

Aorta

Question 10

Blood vessel taking blood out of right ventricle

Answer 10

Pulmonary artery

Question 11

Valves separating atria and ventricles

Answer 11

AV Valves

Question 12

Valves separating ventricles and arteries

Answer 12

Semi-Lunar Valves

Question 13

Function of the coronary arteries

Answer 13

Supply the heart muscle cells with oxygen and glucose for respiration.

Question 14

Why does the left ventricle have the thickest wall

Answer 14

Produce a stronger contraction to create a high blood pressure, as aorta supplies whole body with blood.

Question 15

Blood vessel taking blood to liver

Answer 15

Hepatic artery

Question 16

Blood vessel taking blood away from liver

Answer 16

Hepatic vein

Question 17

Blood vessel taking blood into kidney

Answer 17

Renal artery

Question 18

Blood vessel taking blood away from kidneys

Answer 18

Renal vein

Question 19

How does blood flow remain unidirectional

Answer 19

Blood moves from high to low pressure. AV and semi-lunar valves close to prevent backflow into atria and aorta.

Question 20

Q
What are the 3 stages of the cardiac cycle?

Answer 20

Diastole, atrial systole, ventricular systole.

Question 21

Describe and explain atrial systole

Answer 21

both atria contract
higher pressure in atria than ventricles
blood moves into the ventricles
Increase ventricular volume, decreases atrial volume,
atrial walls contract
AV values open, semi lunar close

Question 22

Describe and explain ventricular systole

Answer 22

Ventricle contracts

causing an increase in pressure in ventricles

So pressure in ventricle is greater than pressure in artery.

So semi-lunar valve opens, AV valve closed.

Blood moves from ventricle to artery.

Volume of ventricle decreases, volume of artery increases.

Question 23

diastole

Answer 23

The atria and ventricular muscles are relaxed.

This is when blood will enter the atria via the vena cava and pulmonary vein.

The blood flowing into the atria increases the pressure within the atria.

Semi- lunar valves close, AV valves open

Question 24

Cardiac output equation

Answer 24

stroke volume x heart rate

Question 25

State the features of the arteries

Answer 25

Thick muscular layer thick elastic layer, thick wall , narrow lumen, smooth endothelium.

Question 26

State the features of the arterioles

Answer 26

Thick muscular layer, thick elastic layer, narrow lumen, smooth endothelium.

Question 27

State the features of veins

Answer 27

Thin muscular layer, thin elastic layer, wide lumen, smooth endothelium, valves.

Question 28

Explain the function of the thick muscular wall in arteries

Answer 28

Can contract to maintain pressure (vasoconstriction).

Question 29

Explain the function of the thick elastic layer in arteries

Answer 29

Stretch when ventricles contract, recoil when ventricles relax. Maintains blood pressure.

Question 30

Explain the function of the thick wall in arteries

Answer 30

Withstand high blood pressure to prevent bursting.

Question 31

Explain the function of narrow lumen in arteries

Answer 31

Maintain blood pressure.

Question 32

Explain the function of smooth endothelium in arteries

Answer 32

Reduce friction.

Question 33

Explain the function of thick muscular layer in arterioles

Answer 33

Can constrict (vasoconstriction) and relax (vasodilation) to control changes in rate of blood flow.

Question 34

Explain the function of thick elastic layer in arterioles

Answer 34

Stretch and recoil to accommodate changes in blood pressure.

Question 35

Explain the function of narrow lumen in arterioles

Answer 35

Maintain blood pressure.

Question 36

Explain the function of smooth endothelium in arterioles

Answer 36

Reduce friction.

Question 37

Explain the function of thin muscular layer in veins

Answer 37

Some ability to contract (vasoconstriction) to maintain pressure.

Question 38

Explain the function of thin elastic layer in veins

Answer 38

Some ability to stretch and recoil to accommodate changes in blood pressure.

Question 39

Explain the function of wide lumen in veins

Answer 39

Reduce friction.

Question 40

Explain the function of smooth endothelium in veins

Answer 40

Reduce friction.

Question 41

Explain the function of valves in veins

Answer 41

Close to prevent backflow.

Question 42

Why is blood slowed in capillaries

Answer 42

More time for exchange of substances.

Question 43

Why is the capillary comprised on a single endothelial cell

Answer 43

Short diffusion pathway, so quick exchange of substances.

Question 44

Explain the formation of tissue fluid

Answer 44

Ventricle contracts to produce a high blood pressure. High blood pressure = high hydrostatic pressure. Hydrostatic pressure is higher at capillary arteriole end than capillary venule end. This pushes water and other small molecules (like glucose) out of capillaries arteriole end, forming tissue fluid.

Question 45

Explain the return of tissue fluid

Answer 45

Plasma proteins remain in blood, as too large to leave. So their concentration at the venule end of the capillary increases. This decreases the water potential of the blood. So water moves into the capillaries venule end by osmosis. Excess tissue fluid is reabsorbed by the lymphatic system.

Question 46

What blood vessel brings oxygenated blood from the lungs to the left atrium?

Answer 46

pulmonary vein

Question 47

heart key

Answer 47

LORD Tri before you bi

Question 48

What blood vessel brings oxygenated blood from the left ventricle to the rest of the body?

Answer 48

Aorta.

Question 49

What blood vessel brings deoxygenated blood from the body to the right atrium

Answer 49

Vena cava.

Question 50

Q What blood vessel brings deoxygenated blood from the right ventricle to the lungs?

Answer 50

Pulmonary artery.

Question 51

What does the vena cava do?

Answer 51

Carries deoxygenated blood from the body to the right atrium.

Question 52

What does the pulmonary vein do?

Answer 52

Carries oxygenated blood from the lungs to the left atrium.

Question 53

What does the pulmonary artery do?

Answer 53

Carries deoxygenated blood from the right ventricle to the lungs.

Question 54

What does the aorta do?

Answer 54

Carries oxygenated blood from the left ventricle to the rest of the body.

Question 55

Describe the mammalian circulatory system:

Answer 55

Closed and double circulatory.

Question 56

Q What does it mean that the mammalian circulatory system is closed?

Answer 56

The blood remains within the blood vessels.

Question 57

Q What does it mean that the mammalian circulatory system is double circulator

Answer 57

The blood passes through the heart twice.

Question 58

Q What blood vessel transports blood from the gut to the liver?

Answer 58

hepatic portal vein

Question 59

How can an arteriole reduce blood flow into capillaries

Answer 59

Muscle contracts, constricting/narrowing the lumen of the arteriole.

Question 60

ow does high blood pressure lead to an accumulation of tissue flu

Answer 60

High blood pressure = high hydrostatic pressure increases outward pressure from arterial end of capillary, so more tissue fluid is formed.

Question 61

What is the role of the heart in the formation of tissue fluid?

Answer 61

A Contraction of the left ventricle produces a high blood/hydrostatic pressure, forcing water and some dissolved substances out of the blood capillaries.

Question 62

What is the X axis of the oxygen dissociation curve?

Answer 62

Partial pressure of oxygen/ kPa --

Question 63

What is the Y axis of the oxygen dissociation curve?

Answer 63

saturation of haemoglobin with oxygen (%)

Question 64

Explain the Bohr effect:

Answer 64

as the amount of CO2 increases, there is a fall in pH which reduces the affinity of haemoglobin for oxygen the haemoglobin changes shape and cannot hold onto the oxygen as easily the Hb moves into a more tense state means that more oxygen unloads in the tissue (for aerobic respiration)

Question 65

Q Give the formula for calculating the percentage saturation of haemoglobin with oxygen. (1)

Answer 65

oxygenated haemoglobin/ maximum saturation) x 100

Question 66

Q Suggest one advantage of the change in the affinity of haemoglobin for oxygen.

Answer 66

allows for the release of oxygen in the tissues

Question 67

Describe the role of haemoglobin in supplying oxygen to the tissues of the body. (2)

Answer 67

haemoglobin binds/associates with oxygen in an area of higher partial pressure of oxygen (lungs) oxygen is released/dissociates in areas of lower partial pressure of oxygen (tissues)

Question 68

Explain how oxygen is loaded, transported and unloaded in the blood. (6)

Answer 68

haemoglobin carries oxygen/has a high affinity for oxygen haemoglobin associates oxygen in the lungs at a high partial pressure of oxygen dissociates to respiring tissues/cells at a low partial pressure of oxygen unloads at a higher carbon dioxide concentration (due to LOWER pH).

Question 69

Explain how the shape of a red blood cell allows it to take up a large amount of oxygen in a short time. (2)

Answer 69

large surface area to volume ratio = for diffusion flat/thin = short diffusion pathway

Question 70

Explain how aerobic respiration in cells leads to a change in the pH of blood plasma. (2)

Answer 70

CO2 is produced in respiration forms carbonic acid

Question 71

What is the advantage to tissue cells of a reduction in the affinity of haemoglobin for oxygen when the plasma pH decreases?

Answer 71

low pH due to a high rate of respiration (more CO2 produced) Cells need more O2 More O2 released/released faster.

Question 72

Q What happens to hemoglobin’s affinity for oxygen when the dissociation curve shifts right?

Answer 72

affinity for oxygen decreases

Question 73

The data in Table 7 show differences between the oxyhaemoglobin dissociation curve for a mouse and the oxyhaemoglobin dissociation curve for a horse. Suggest how these differences allow the mouse to have a higher metabolic rate than the horse [2 marks] the horse.

Answer 73

A Mouse haemoglobin/Hb has a lower affinity for oxygen For the same pO2 the mouse haemoglobin/Hb is less saturated At oxygen concentrations found in tissue mouse haemoglobin/Hb is less saturated; More oxygen can be dissociated/released/unloaded (for metabolic reactions/respiration);