Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

2. Cardiovascular System > 13. Short Term Control of BP > Flashcards

13. Short Term Control of BP Flashcards

1
Q

What is the equation for calculating MAP?

A

MAP= CO x TPR

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

What can low MAP cause?

A

fainting (syncope_

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

What can high MAP cause?

A

hypertension; overtime damages capillary beds leading to cardiovascular disease, stroke etc

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

Where are baroreceptors found? (2)

A
  1. at the carotid sinus (at internal carotid arteries)

2. at the aortic arch

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

What effect does pressure in arteries have on vessel stretchability?

A

Makes arteries more stretchable when high pressure is detected during bigger APs

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

What is resting arterial pressure?

A

-90mmHg

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

Where do baroreceptors send their impulses to?

A

to the medulla of the brain (cardiovascular centre) which compares the blood pressure

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

What are baroreceptors?

A
  • stretch receptors

- fire more APs if detect high pressure and stretch artery walls

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

What is the carotid sinus?

A

area where internal and external carotid arteries split (bifurcate)

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

What is the AP firing rate throughout the cardiac cycle?

A

Most APs fired at systole and least APs fired during diastole

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

What nerve sends signals from the carotid sinus baroreceptors to the medulla?

A

glassopharyngeal nerve

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

What nerve sends signals from the aortic arch baroreceptors to the medulla?

A

vagus nerve

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

What 2 nerves travel AWAY from the medulla towards the heart?

A
  1. sympathetic nerves

2. parasympathetic (vagus) nerves

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

What do sympathetic and parasympathetic nerves from the medulla innervate in the heart?

A

the SA node

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

What receptors do sympathetic nerves act on?

A

alpha 1 receptors

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

What is the effect of the sympathetic nerves on the heart?

A
  • cause blood vessel constriction
  • cardiac output and stroke volume will increase
  • increase in TPR
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are other inputs to the medullary cardiovascular centres? (5)

A
  1. cardiopulmonary baroreceptors
  2. central chemoreceptors
  3. chemoreceptors in muscle
  4. joint receptors
  5. higher centres
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is another name for cardiopulmonary baroreceptors?

A

low pressure baroreceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What happens to baroreceptors firing rate during hypertension and hypotension?

A

Hypertension; increase

Hypotension; decrease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What does decreased sympathetic tone do to lower heart rate? (4)

i.e. increased vagal tone

A
  • reduces veno/arteriolar constriction
  • reduce adrenaline production in adrenal medulla
  • reduce contractility
  • reduce heart rate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does decreased vagal tone do to increase heart rate? (4)

i.e. increased sympathetic tone

A
  • increases veno and arterial constriction ( increases venomotor tone)
  • increases adrenaline production in adrenal medulla
  • increases contractility
  • increases heart rate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How do signals travel from the medullary CV centres to the veins/arteries smooth muscle?

A

sympathetic nerves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What carries signals from the medullary CV centres to the adrenal medulla?

A

sympathetic nerves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

From which spinal level do sympathetic nerves supplying the heart arise from?

A

T5-8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What do chemoreceptors respond to?
- respond to Co2 changes which cause pH changes in the CSF - CSF is closely related to blood - induces heart to pump more O2 around body in hypoxic situations
26
When are joint receptors activated?
activated during physical activity (during repeated movement)
27
How does activating central chemoreceptors affect MAP?
Activated when high CO2; means increased heart rate and contractility and therefore increased cardiac output and MAP
28
When do chemoreceptors specifically activate?
during exercise
29
What group of receptors are classified as "feedback receptors"?
1. cardiopulmonary baroreceptors ( low pressure baroreceptors) 2. central chemoreceptors 3. chemoreceptors in muscle
30
How do higher centres (hypothalamus and cortex) affect MAP before exercise?
- act as feed-forward systems - tells CV system that something is about to happen and pre-prepares it to increase the CO - gets CV system working before stimulus occurs to be prepared for increase in heart rate in anticipation for blood to muscles
31
Can arterial baroreceptors control and regulate BP in the long run?
No, they can't
32
What does regulation of BP in the long run revolve around?
revolves around blood volume
33
What are the main sensors which regulate BP in the long run?
cardio-pulmonary baroreceptors
34
In cardiopulmonary baroreceptors, what do their effect tend to be produced as?
hormonal effect
35
What structures does hormonal effect mainly influence? (2)
1. blood vessels | 2. kidneys
36
Why is arterial baroreceptor reflex important when standing up?
Prevents body from fainting when all the blood rushes to the feet
37
How does standing affect MAP?
Lower venous return as blood pools in legs causing venous distension. - lower EDV - lower preload - lower SV - lower CO - lower MAP
38
Define valsalva manoeuvre.
Forced expiration against a closed glottis
39
What does valsalva mamoeuvre cause first in the thorax?
increase in thoracic pressure
40
How does increased thoracic pressure affect aortic pressure?
It's transmitted through the aorta where it's added to aortic pressure; therefore MAP rises
41
How does increased thoracic pressure affect venous return?
Increased thoracic pressure reduces venous return because it squashes the veins near the heart preventing blood flow.
42
How does lowered venous return affect MAP?
As less blood gets back to the heart EDV lowers. Hence CO lowers and MAP falls. This happens steadily so you get a gradual reduction in MAP back towards normal.
43
What is the bodies response to lowered MAP?
When MAP falls below normal (due to reduced VR) it triggers the baroreceptor reflex which makes MAP rise again
44
When the valsalva manoeuvre ends the decreased thoracic pressure is transmitted to the aorta, what effect does this have on the MAP?
Reduces MAP significantly (large drop below resting level)
45
How does returning back to normal venous return after the valsalva manoeuvre affect MAP?
- After the valasalva manoeuvre thoracic pressure returns to normal so venous return does too. - EDV returns to normal and MAP quickly rises again. - Since the baroreflex is still active MAP rises well above normal
46
What happens to BP after the valsalva manoeuvre after the baroreflex wears off?
BP returns to normal
47
What is the risk to elderly who go through a valsala manoeuvre?
Their CVS can't cope with the variations in MAP, particularly the sudden hypotension when thoracic pressure returns to normal (common for elderly to faint or have heart attacks)
48
What hormone system regulates MAP in the long term?
renin-angiotensin- aldosterone system
49
What effect on arterioles does angiotensin II have?
It causes constriction and therefore increase in TPR
50
What effect does aldosterone have on cells? (2)
- increase Na reabsorption | - increase in plasma volume
51
What effect does vasopressin (antidiuretic) hormone have on arterioles? (4)
- causes arteriolar constriction - increase in TPR - increased water permeability of collecting duct - increase in plasma volume
52
What effect do atrial natriuretic peptide and brain natriuretic peptide have on arterioles? (4)
- cause arteriolar dilation - decrease in TPR - increase in Na (natriuresis) - decrease in blood volume
53
In summary what 3 hormone groups are involved in long term control of BP?
1. renin-angiotensin- aldosterone system 2. vasopressin (antidiuretic) 3. atrial natriuretic peptide and brain natriuretic peptide
54
What are 2 ways in which posture affects the BP?
1. effect of standing | 2. the reflex response
55
What effect does standing have on the hydrostatic pressure?
Increased hydrostatic pressure causes pooling of blood in veins/ venules of feet/ legs (naturally decreases BP)
56
What effect does standing have on: VR, EDV, preload, SV, CO, MAP, baroreceptor firing rate
``` decrease VR decrease EDV decrease preload decrease SV decrease CO decrease MAP decrease baroreceptor firing rate ```
57
What is the reflex response?
naturally responds to standing (adrenaline will have the same effect to it; wakes up the circulatory system by increasing the dropping BP)
58
What does a DECREASE in vagal tone cause in reflex response? (putting the parasympathetic system to sleep) (2)
- decrease in heart rate | - decrease in cardiac output
59
What does an INCREASE in sympathetic tone cause in a reflex response? (in terms of; HR, CO, SV, VR, EDV, TPR)
``` increase heart rate increase cardiac output increase stroke volume increase venous return increase end diastolic volume increase TPR (through vasoconstriction) ```
60
What happens to the pressure in thorax during valsalva manoeuvre? Why does it affect MAP ultimately?
Increased thoracic pressure is transmitted through aorta which affects MAP ultimately
61
What effect does increased thoracic pressure have on; | VR, EDV, SV, CO and MAP
``` decrease VR decrease EDV decrease SV decrease CO decrease MAP ```
62
What is decrease in MAP detected by? (during a valsalva manoeuvre) What do these initiate?
detected by baroreceptors; which initiate reflex response
63
What effect does reflex response have on CO and TPR?
- increase CO | - increase TPR
64
Why does the valsalva manoeuvre graph continue on after BP has been stabilised and stroke volume increases once more to normal?
because reflex effects have not worn off
65
Why can the valsalva manoeuvre be used to test a patient's arteriobaro reflex?
it will continue to fall without stabilising in a patient with poor baroreflex
66
In summary what are the main features of the pumping ability of the heart? (4)
1. structure 2. electrical activity 3. cardiac cycle 4. control of HR and SV
67
What are 2 controls of arterioles and what do they control?
1. Local: to meet needs of tissues | 2. Central: to regulate MAP
68
What is the central control of MAP?
arterial baroreflex system

2. Cardiovascular System (42 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions