Feedback Control with cardiovascular system Flashcards

1
Q

What is blood pressure? (general)

A

Blood pressure is the outwards (hydrostatic) pressure exerted by the blood on blood vessel walls.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is pulse pressure?

A

The difference between systolic and diastolic blood pressure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the systolic blood pressure?

A

The pressure exerted by the blood on the walls of the aorta and the systemic arteries when the heart contracts.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the diastolic blood pressure?

A

The pressure exerted by the blood on the walls of the aorta and the systemic arteries when the heart relaxes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the mean arterial blood pressure? (MAP)

A

The average arterial blood pressure during a single cardiac cycle which involves contraction and relaxation of the heart.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why does MAP need to be tightly regulated?

A

To ensure the blood pressure is high enough to perfuse vital organs but not too high that it would damage blood vessels or cause strain on the heart and other organs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the baroreceptor reflex?

A

A short-term regulatory mechanism of the mean arterial blood pressure via negative feedback.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the sensors called in the negative feedback control of MAP?

A

baroreceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the control centre called in the negative feedback control of MAP?

A

Medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the effectors called in the negative feedback control of MAP?

A

Heart and blood vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the two main types of baroreceptors?

A

Carotid baroreceptors and aortic baroreceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why can’t MAP be calculated by averaging the systolic and diastolic pressures?

A

The diastolic period is twice as long as the systolic portion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What happens to the firing rate of baroreceptors if MAP is increased/decreased?

A

If the MAP increases, the firing rate of baroreceptors afferent neurons increases.
If the MAP decreases, the firing rate of baroreceptors afferent neurons decreases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Define cardiac output (CO).

A

The volume of blood pumped by each ventricle of heart per minute

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Define stroke volume (SV).

A

The volume of blood pumped by each ventricle per heart beat.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Define systemic vascular resistance (SVR).

A

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

17
Q

What is the formula/relationship between MAP, cardiac output and systemic vascular resistance?

A

MAP= CO X SVR

18
Q

What is the formula/relationship between MAP, stroke volume and heart rate?

A

MAP= SV X HR

19
Q

MAP can be regulating by regulating…

A

Heart rate , stroke volume and

systemic vascular resistance

20
Q

What is vasomotor tone?

A

Vascular smooth muscles have a tonic supply of sympathetic nerves meaning they are partially constricted at rest.

21
Q

What are the two formulas for calculating MAP from systolic and diastolic blood pressure?

A

Formula 1:
MAP= [ (2x diastolic) + systolic] divided by 3

Formula 2:
MAP= Diastolic blood pressure + 1/3 pulse pressure

22
Q

What does the Nucleus tractus solitarius (NTS) do?

A

It is the first synapse site for all CVS afferents in the medulla.
It relays info to other regions in the brain e.g. hypothalamus.
It also modulates the activity of the autonomic nervous system.

23
Q

What does autorhythmicity mean?

A

The ability of creating its own rhythm i.e. the heart beating rhythmically in the absence of the external stimuli.

24
Q

What will decreasing or increasing the sympathetic discharge do to the vasomotor tone?

A

Decreasing sympathetic discharge will decrease vasomotor tone.

Increasing sympathetic discharge will increase the vasomotor tone.

25
Q

What will happen to the baroreceptors if high blood pressure is sustained?

A

The baroreceptors will reset and only fire again when there is a new change to the new steady state level.

26
Q

What does vascular smooth muscle contraction or relaxation cause?

A

Contraction of vascular smooth muscles causes vasoconstriction and increases SVR and MAP

Relaxation of vascular smooth muscles causes vasodilation and decreases the SVR and MAP