Mass Transport PPQs

Question 1

During the cardiac cycle changes in pressure cooker and the left atrium and left ventricle. Used graph and your own knowledge to explain these differences. (5)

Answer 1

(mp1) Difference: pressure changes in atrium are smaller than pressure changes in ventricles

Explanation:

(mp2) - bc atrium has less cardiac muscle than ventricles
(mp3) - because DOESNT have to pump blood as far as ventricles (to rest of body)

(mp4) Difference: atria increase in pressure before ventricles increase in pressure

Explanation:

(mp5) - atriole systole must happen before ventricular systole so ventricles can fill with blood
(mp6) - increase in atrial pressure caused increase in pressure in ventricles

mp7 - pressure in atrium larger than pressure in ventricle so atrioventricular valve opens preventing further significant increase in pressure in atrium

Question 2

At which time does the valve between the atrium and ventricle close? (1)

Answer 2

0.10s

Thought process:
Ventricular pressure is rising
Ventricular pressure only rises once the atrioventricular valve has shut
So the valve must shut when the ventricular pressure starts rising
Which is at 0.10 seconds

Question 3

To risk factors of coronary heart disease

Answer 3

Smoking

High blood cholesterol

Question 4

Use information from the figure to explain how the pressure in the dogs ventricle is related to bloodflow

Answer 4

Pressure increases THEN blood flows into aorta

Because increasing pressure CAUSES semi lunar to open

Ventricle pressure starts to fall to blood flow to aorta starts to fall

Question 5

Use information from the figure to explain how the pressure in the dogs ventricle relates to the thickness of the ventricle wall (2)

Answer 5

Thickness increases because the ventricle contracts

Contraption causes an increase in pressure

Question 6

Explain the importance of maintaining a constant blood pH(3)

Answer 6

Hb affected by change in pH

Change to tertiary structure

Less oxygen binds to Hb

Question 7

Although the speed of bloodflow in an arterial is greater than the speed of bloodflow in a capillary, large does not accumulate in the arterioles.

Explain why (1)

Answer 7

More capillaries an artériole

Area of capillaries is larger than the area of the artériole

Question 8

Other than causing slow bloodflow explain one advantage of the capillaries being narrow (1)

Answer 8

Larger surface area of blood in contact with capillary walls

Short diffusionpathway (distance between blood and outside of capillaries)

Question 9

What factor limits the minimal internal diameter of the lumen of a capillary?

Answer 9

Size of red blood cell

Question 10

The volume of blood leaving the capillary network into the vein is less than the volume of blood entering from the arteries.

Explain why. (1)

Answer 10

Fluid from blood has been squeezed out to form tissue fluid

Question 11

During a heart attack part of the heart muscle dies explain why (3)

Answer 11

Coronary arteries blocked
NOT ENOUGH oxygen reaches respiring cells
Respiration stops

Question 12

The thickness of the iota wall changes all the time during the cardiac cycle. Explain why (3)

Answer 12

Aorta wall stretches because ventricle contracts

Aorta wall recoils because ventricle relaxes

To maintain blood pressure

Question 13

Describe how tissue fluid is formed and how is returned to the circular Tory system (6)

Answer 13

X

Question 14

Describe how haemoglobin on loads and loads oxygen in the body (3)

Answer 14

Loads at high partial pressures and has high affinity and is in LUNGS
Unloads at low partial pressures and has low affinity

Question 15

Smaller mammals have

Answer 15

LARGER SA:V

Question 16

What does a larger SA:V mean ??

Answer 16

More heat loss

Question 17

Heat from respiration helps mammals to maintain a constant body temperature.

Useless information to explain the relationship between the surface area to volume ratio of mammals and oxygen dissociation curve of the haemoglobins.

Answer 17

Small animals have larger SA:V so lose more heat

So have a greater rate of respiration

So Hb curves shifts right

Hb has lower affinity and lower partial pressures so easier unloading of oxygen to repairing cells

Question 18

What is meant by the term partial pressure (1)

Answer 18

Measure of the concentration of the gas in a mixture of gases

Question 19

Why is oxygen partial pressure at the tissues lower during exercise?

Answer 19

Increased oxygen consumption Lowes tissue partial pressure of oxygen

Question 20

Does enriching inspired air with oxygen have any effect on the amount of oxygen reaching the tissues? Support your answer with evidence from the graph and table 2.

XXX

Answer 20

X

Question 21

Give two ways in which the total oxygen supply to the muscles during exercise is increased. (3 ways)

Answer 21

Increased depth of pulmonary ventilation

Increased heart rate

Greater proportion of bloodflow to the muscles by arterioles dilating

Question 22

Explain the role of the heart in the formation of tissue fluid. (2)

Answer 22

High hydrostatic pressure produced from ventricle contracting

Forces water out of the capillaries

Question 23

Cause of lymphoedema

Answer 23

Excess tissue fluid builds up

Question 24

The scientist concluded that treatment with hydroxyurea would increase the concentration of oxygen in the blood of babies with sickle-cell disease.

Suggest how the graph and the table above support this conclusion. (3)

Answer 24

After treatment mean concentration of HBF in the babies blood significantly increased

HBF has a higher affinity for oxygen

High proportion of HBF in the blood means more oxygen is carried

Question 25

Explain how the changes in the shape of haemoglobin result in the sigmoid Oxy haemoglobin dissociation curve (2)

Answer 25

First oxygen binds to haemoglobin causing it to change shape Allows other oxygen to bind more easily

Question 26

Use the graph to explain why this change is an advantage for the baby (2)

Answer 26

HP a has a lower affinity for oxygen at low partial pressures So easier unloading of oxygen for respiration

Question 27

Explain for ways in which the structure of the aorta is related to its function (4)

Answer 27

Elastic tissues allows stretching Smooth endothelium reduces friction Musculaire all withstands high pressures Aortic valve prevents back flow Muscle for contraction Elastic tissues stretches when ventricles contract

Question 28

How many milliseconds in one second

Answer 28

1000

Question 29

Explain how the heart muscle and the heart valves maintain a one-way flow of blood from the left atrium to the a water (5)

Answer 29

Atrial pressure exceeds ventricular pressure Causing atrioventricular valve to open Ventricular pressure exceeds atrium pressure Causing atrioventricular valve to close Ventricular pressure exceeds a water pressure Causing semilunar valve to open Aorta pressure exceeds ventricle pressure (as the heart relaxes) Causing semilunar valve to close Contraction causes an increase in pressure

Question 30

Suggest where the left ventricle requires the help of the artificial heart but the right ventricle does not (2)

Answer 30

Left ventricle produces a greater pressure (must pump blood at higher pressure is) Because it must pump blood to the WHOLE of the body

Question 31

What do these data show about the effect of glycaemic load on the diet has on the risk of developing coronary heart disease ? (1)

Answer 31

No affect on risk in diet groups one and two For diet group 2 and above increased risk of CHD as GL increases

Question 32

Use the information provided to explain the effect that glycaemic load of the diet has on the risk of developing coronary heart disease (2)

Answer 32

For diet groups two and above, and increase risk of CHD as GL increase is because increase concentration of harmful lipids in the blood So increased risk of atheroma Atheroma leads to blockage of coronary artery