Heart

Question 1

Some babies are born with hole between right and left ventricle

These babies are unable to get enough oxygen to their tissues
Explain why

2 marks

Answer 1

1) Deoxygenated and oxygenated blood travel the wrong way - deoxygenated and oxygenated would mix

2) Lowers the volume of oxygenated blood that leaves the left ventricles

3) less oxygen reaches tissues

Question 2

Explain how arteriole can reduce blood flow into the capillaries?

2 marks

Answer 2

Muscle contracts
Narrows lumen

Question 3

What do you always mention when talking about values being shut.

Answer 3

That there will be no back flow.

Question 4

In a healthy person, blood moves in one direction as it passes through the heart.

Give two details which this is achieved

2 marks

Answer 4

valves stop backflow

Pressure gradient - moves from high to low pressure
Ventricle pressure rises so blood can flow into the aorta through SL valve being open

Question 5

Explain how the pressure in ventricle is related to blood flow into the aorta

2 marks

Answer 5

The increase in ventricle pressure, reduces the volume of ventricle
So blood flow into the aorta increases through the SL valve being open
When aorta pressure is higher than ventricle the valve closes

The ventricle pressure decreases so does the blood flow

Question 6

Explain how pressure in ventricle is related to thickness of ventricle wall

2 marks

Answer 6

Thickness of the wall increases because ventricle wall contracts

Increases pressure

Question 7

How is the atrium adapted?

Answer 7

Has elastic walls to stretch when blood enters

Question 8

There is a small increases in pressure and in rate of blood flow in the aorta

Explain how this happens and its importance

2 marks

Answer 8

1. Elastic recoil
2. Smooth the blood flow
   Maintain rate of blood flow
   Maintain blood pressure

Question 9

On a cardiac cycle graph the right and left ventricle was plotted on the same grid

Name the similarity
1 mark

Answer 9

Peak/ contraction happen happen at same/ similar time

Same / similar pattern

Question 10

Name the blood vessel that carry blood to the heart muscle

1 mark

Answer 10

Coronary artery

Question 11

Explain how the highest blood pressure is produced in left ventricle

1 mark

Answer 11

Strongest / stronger contractions (1)

Can say thicker muscular wall compared to right ventricles

Question 12

If given a table with the time/sec and the volume of blood in left ventricle /cm3

How could you identify the heart rate in beats per minute

1 mark

Answer 12

Look for where the volume of blood begins the pattern of numbers again

Meaning when the pattern starts to repeat that is equal to one heartbeat

So you correlate it to the time taken

Question 13

Outline the steps to calculate vol of blood pumped from cardiac cycle graph

Answer 13

1. Find the value of one square
2. Find how many squares between two peaks
3. Do the number of squares between peaks times value of one square
4. 1 divided by number you just worked out
5. Times the answer you just got by 60
   (= Heart rate)
6. For the volume do highest point - lowest point on graph with line
   Times that by the heart rate