4: Feedback control of the cardiovascular system

Question 1

What is blood pressure?

Answer 1

The outward pressure exerted by the blood on blood vessel walls

Question 2

What is systolic blood pressure?

Answer 2

The pressure exerted on the walls of the blood vessels when the heart contracts

Question 3

What value (mm Hg) is systolic blood pressure usually LESS THAN?

Answer 3

140

Question 4

What is diastolic blood pressure?

Answer 4

The pressure exerted on the walls of the blood vessels when the heart relaxes

Question 5

What value (mm Hg) is diastolic blood pressure usually LESS THAN?

Answer 5

90

Question 6

What is Mean Arterial Blood Pressure (MAP)?

Answer 6

The average arterial blood pressure during a single cardiac cycle

Question 7

Why ISN’T MAP taken by averaging the systolic and diastolic blood pressures?

Answer 7

Time taken for relaxation is twice as long as that taken for contraction

Question 8

How is MAP calculated

Answer 8

MAP = [(2x Diastolic) + Systolic)] divided by 3

Question 9

What is the normal range of Mean Arterial Blood Pressure (MAP) in mm Hg?

Answer 9

70 - 105

Question 10

What is the minimum MAP (in mm Hg) needed to perfuse the coronary arteries, brain and kidneys?

Answer 10

60

Question 11

In which two areas are baroreceptors found?

Answer 11

1. Aortic arch (Aortic baroreceptors)

2. Carotid sinus (Carotid baroreceptors)

Question 12

What are baroreceptors?

Answer 12

Receptors responsible for regulating blood pressure

Question 13

What happens to the firing rate of baroreceptors when MAP increases?

Answer 13

It also increases

Question 14

What happens to the firing rate of baroreceptors when MAP decreases?

Answer 14

It also decreases

Question 15

What is the cardiovascular control centre called?

Answer 15

Medulla

Question 16

What is the cardiac output (CO)?

Answer 16

The volume of blood pumped by EACH VENTRICLE of the heart PER MINUTE

Question 17

What is the stroke volume?

Answer 17

The volume of blood pumped by EACH VENTRICLE of the heart PER HEARTBEAT

Question 18

Give an equation for cardiac output.

Answer 18

Cardiac output = Stroke volume x Heart rate

Question 19

Give an equation for MAP.

Answer 19

Mean Arterial Pressure = Cardiac Output x Total Peripheral Resistance

Question 20

What is Total Peripheral Resistance?

Answer 20

The sum of all the resistance in all of the systemic circulation

Question 21

What is autorhythmicity?

Answer 21

The heart being able to beat automatically in the absence of any external stimuli

Question 22

Which nervous division ACCELERATES the heart rate?

Answer 22

Sympathetic

Question 23

Which nervous division SLOWS the heart rate?

Answer 23

Parasympathetic

Question 24

What is tachycardia?

Answer 24

Increase in heart rate

Question 25

What is bradycardia?

Answer 25

Decrease in heart rate?

Question 26

Which nervous division is involved in regulating stroke volume?

Answer 26

Sympathetic

Question 27

What type of controls regulate stroke volume?

Answer 27

Intrinsic (within the heart)

Question 28

What type of muscle regulates total peripheral resistance?

Answer 28

Smooth muscle

Question 29

Where is the majority of TPR found?

Answer 29

Arterioles

Question 30

What does vasoconstriction do to TPR and MAP?

Answer 30

Increases them both

Question 31

What does vasodilation do to TPR and MAP?

Answer 31

Decreases them both

Question 32

Vascular smooth muscles are partially constricted at rest. This is called _____ ____.

Answer 32

Vasomotor tone

Question 33

What controls vasomotor tone?

Answer 33

Discharge of sympathetic nerves resulting in continuous release of noradrenaline

Question 34

What neurotransmitter is involved in sympathetic control of vascular smooth muscle?

Answer 34

Noradrenaline

Question 35

Increased sympathetic discharge will ____ vasomotor tone resulting in ________.

Answer 35

increase , vasoconstriction

Question 36

Decreased sympathetic discharge will ____ vasomotor tone resulting in ________.

Answer 36

decrease , vasodilation

Question 37

Baroreceptors only respond to _____ changes in blood pressure.

Answer 37

acute