A3 Cardiovascular and respiratory system

Question 1

What are the four blood vessels in the heart?

Answer 1

Aorta, vena cava, pulmonary vein, pulmonary artery

Question 2

What are the valves in the heart?

Answer 2

2 semilunar valves, 2 AV valves

Question 3

Describe blood circulation

Answer 3

Deoxygenated blood from the body enters the heart from vena cava into the right atrium down through other valves then the right ventricle then the pulmonary artery then the lungs then the pulmonary vein, left atrium valves left v aorta

Question 4

What are the main chambers in the heart?

Answer 4

Right atrium, right ventricle, left atrium, left ventricle

Question 5

What is the role of SAN?

Answer 5

Stimulates the cardiac muscle contract

Question 6

What is the role of purkinje fibres?

Answer 6

To conduct electrical impulses to the bottom of the heart so that it contracts from the base upwards

Question 7

How is the cardiac cycle controlled?

Answer 7

SAN produce a wave of electrical activity - spreads through atrium causing artia walls to contract
Lack of conducting tissue between SAN and AVN causes time delay for electrical activity allowing atria contraction to finish before ventricular contraction starts.
The electrical activity is then taken up by the AVN and passed down to the base of the heart by the bundle of His
The electrical activity then spreads into the ventricular walls causing ventricles to contract from base upwards
Blood gets pushed up the aorta and pulmonary artery

Question 8

What is the pulmonary circulatory system?

Answer 8

The heart, lungs and all associated blood vessels that circulate blood to and from the lungs

Question 9

In what order, what helps to make the heart beat?

Answer 9

SAN, AVN, bundle of his then purkinji fibres

Question 10

What is blood composed of?

Answer 10

Red blood cells, plasma cells and white blood cells

Question 11

Describe one adaptation of the artery

Answer 11

Thick walls so blood can be carried at a high pressure

Question 12

How is heart rate controlled?

Answer 12

It is controlled by the autonomic nervous system

Question 13

How is blood pressure measured?

Answer 13

Systolic and diastolic blood pressure

Question 14

What can cause high blood pressure?

Answer 14

Eating too much salt, being overweight, drinking too much alcohol

Question 15

What is the typical blood pressure reading?

Answer 15

120/80 mmHg (this can vary from person to person).
120 refers to pressure in the artery when the ventricle contracts and is the systolic pressure
80 refers to the pressure in the artery when the heart relaxes and is the diastolic pressure.

Question 16

How does the sphygmomanometer work?

Answer 16

1)
2)
3)

Question 17

What causes the heart rate to slow down?

Answer 17

The parasympathetic nerve stimulates it

Question 18

What causes the heart rate to speed up?

Answer 18

When the sympathetic nerve stimulates it

Question 19

What happens when we inhale carbon dioxide?

Answer 19

It goes into the blood and it become carbonic acid which lowers blood pH (makes it more acidic)

Question 20

What are baroreceptors and why is it considered a reflex?

Answer 20

Cells that detect blood pressure and it is a reflex because it is automatic

Question 21

Why is the baroreflex considered a negative feedback loop?

Answer 21

The body responds to counteract change

Question 22

What are chemoreceptors and what it is involved in?

Answer 22

Cells that detect changes in blood pH. It is sensitive to the levels of CO2 levels in the blood. It is also involved in controlling breathing rate using intercostal muscles and the ventilation centre in the medulla.

Question 23

How does the autonomic nervous system control heart rate?

Question 24

What does blood pressure affect?

Answer 24

The cardiac output

Question 25

Where are the baroreceptors located?

Answer 25

In the sinuses of the carotid arteries in the neck and the aorta

Question 26

Where is the chemoreceptor located?

Answer 26

In the aorta and carotid arteries

Question 27

What happens when CO2 levels increase?

Answer 27

pH of blood goes down.
This is detected by chemoreceptors which is aorta
They send impulses along the sensory neurone to the cardiac centre.
This results in an increased number of impulses travelling along the sympathetic nerve releasing more noradrenaline onto the SAN to stimulate the heart more.
This leads to an increase in heart rate, giving increased blood flow to the lungs which speeds up the removal of CO2 from the blood.

Question 28

What happens when CO2 levels decrease?

Answer 28

pH of blood goes up.
This is detected by chemoreceptors
They send electrical impulses to the cardiac centre via sensory nerve
Cardiac centre sends reduced number of impulses along the sympathetic nerve to the heart

Question 29

Where are the lungs located?

Answer 29

The thoracic cavity surrounded by pleural membranes which encloses an airtight space

Question 30

What does the space contain in the lungs and what does it allow for?

Answer 30

The space contains small amount of fluid to allow friction - free m