Lecture 10

Question 1

Which structure generates pressure for systemic circulation?

Answer 1

Left ventricle generates lots of power which is needed to highly pressurise the system

Question 2

Why is a large pressure difference importance?

Answer 2

Used to drive blood around our system.If there was a decrease in pressure there would be reduced circulation to the brain

Question 3

Describe the change in blood pressure throughout systemic circulation?

Answer 3

BP high in major arteries (oscillatory) - falls around arterioles, capillaries and venules (oscillatory. nature is reduced) - very low in veins

Question 4

How does blood flow in affect arterial blood volume and pressure?

Answer 4

Fills arteries
Increases arterial blood volume
Raises arterial pressure

Question 5

How does blood flow out affect arterial blood volume and pressure?

Answer 5

Drains arteries
decreases arterial blood volume
Lowers arterial pressure

Question 6

What determines mean arterial blood pressure?

Answer 6

balance between flow in and flow out

Question 7

what is cardiac output?

Answer 7

flow of blood out of ventricles into arteries

Question 8

What is cardiac output dependent on?

Answer 8

Resistance of drainage of blood out of arteries into capillary beds

Question 9

What happens if mean arterial pressure is too low?

Answer 9

Cardiac output increases

Question 10

what happens if mean arterial pressure is too high?

Answer 10

Increases resistance, making it more difficult for blood to flow out into capillary beds which will increase pressure again

Question 11

What is the equation for mean arterial pressure?

Answer 11

MAP = CO x TPR

Question 12

What is stroke volume?

Answer 12

Volume of blood that is getting pushed out every time your heart beats (measured in L per minute)

Question 13

What is the purpose of stroke volume?

Answer 13

Determines how strongly and quickly our heart is contracting

Question 14

How can cardiac output be driven differently?

Answer 14

Low stroke volume but very fast heart beat.

Or High stroke volume but slow heartbeat

Question 15

Heart disease?

Answer 15

When the walls of the heart become stiff and don’t contract as well, stroke volume goes down however metabolic needs stay the same. To compensate for this the heart rate increases which puts the heart under immense stress

Question 16

Ids cardiac output s set value?

Answer 16

No, it is highly variable considering our metabolic needs fluctuate.

Question 17

How is homeostasis of arterial blood pressure maintained?

Answer 17

The brain is able to determine blood pressure out in our arteries and then make changes to it if necessary

Question 18

What is afferent input?

Answer 18

Communication/signals from various parts of the body which the brain receives

Question 19

What is efferent output?

Answer 19

Signals sent from brain to make changes around the body

Question 20

What are baroreceptors?

Answer 20

Blood pressure sensors that measure blood pressure.

Question 21

Where are baroreceptors located?

Answer 21

Heavily concentrated in aortic and carotid sinus/arteries

Question 22

How do baroreceptors measure BP?

Answer 22

They sense a stretch in arteries. They are constantly sending afferent input (signal with a pce) to the brain.

Question 23

How does gravity effect stroke volume?

Answer 23

In an upright position blood vessels are working against gravity which decreases stroke volume. This means cardiac output also falls slightly. Only slightly because as stroke volume falls , heart rate will compensate by increasing