Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PHSL 232 > L10 > Flashcards

L10 Flashcards

1
Q

how is arterial pressure controlled

A

homeostatically

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

what is arterial pressure precisely regulated at

A

90mmHg

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

why do we need perfusion pressure

A

to overcome the resistance of arterioles

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

what does perfusion pressure enable

A

precise control of regional blood flow by manipulating only the regional resistance.

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

how is arterial blood pressure regulated

A

through a negative feedback loop

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

where are the sensors that detect blood pressure located

A

baroreceptors in the aortic arch and carotid sinus

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

how do baroreceptors work

A

they are collections of cells that detect stretch in the arterial walls.

an increases in stretch = an increase in pressure which causes an increase in the action potentials that those cells
fire.

this is the opposite for when there is a decrease in stretch therefore baroreceptors are tonically active

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

what is the afferent pathway for aortic baroreceptors

A

Aortic baroreceptors –>aortic nerve –> vagus (cranial nerve X)

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

what is the afferent pathway for carotid baroreceptors

A

Carotid baroreceptors – carotid sinus nerve – glossopharyngeal nerve

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

do the nerves associated with baroreceptors fire with systole and diastole

A

yes

each cardiac cycle distends the arterial wall therefore when you look at when the baroreceptors fire peak to peak = 1 cardiac cycle

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

what is blood pressure regulation important for

A

this is important for regulation short term changes in BP eg sitting to standing

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

what are bidirectional changes

A

long term

when nerve activity either increases or decreases because of changes in MABP

small change = small response

large change = large response

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

what is the integrator in the blood pressure regulation system

A

nucleus tracts solitarius (NTS) in the medulla

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

who does the NTS work

A

it receives afferent information from the B receptors

the NTS then takes this info, processes it and sends efferent signals to the heart and periphery to do things so that we can get BP back to normal

This involves pre and postganglionic nerves and both the sympathetic and parasympathetic NS

P = heart 
S= heart and vasculature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the baroreflex action in para and sympathetic NS

A

increase in pressure = increase in firing. the reflex via cardiovascular centre in the medulla causes an increase in parasympathetic outflow to the heart and a decrease in sympathetic outflow to the heart arterioles and veins

this leads to decreased contractility and vasodilation

opposite for decrease

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

what is an example of a hemostatic challenge

A

a haemorrhage

this is an escape of blood from a ruptured vessel

17
Q

what are the 3 stages of restoration when you have a haemorrhage

A

baroreflex

cardiovascular volume restoration

total body volume restoration

18
Q

when do the 3 stages of restoration occur after a haemorrhage

A

baroreflex = immediate

cardiovascular volume restoration = immediate

total body volume restoration = long term

19
Q

what is the baroreflex (what happens in heart, veins and arterioles)

A

the baroreflex is rapid changes in para/simpathetic outflow to restore MABP towards the heart

the effect on the heart is increased HR and SV which leads to increases CO –> MABP

veins = venoconstriction, increases VR and EDV. this leads to in increases in CO –> increased MABP

arterioles = vasoconstriction –> increases TPR –> increases MABP

20
Q

why do we have cardiovascular volume restoration

A

it takes 4 -8 weeks to fully replace RBC lost in a haemorrhage but we need to restore the volume

we do this via absorption of fluid from interstitial fluid
by capillaries to increase blood volume.

this happens because vasoconstriction causes decreases hydrostatic pressure which is the main driving force for fluid out of the cell

Reduced amount out and increased amount in

This is tissue specific. Most of the reabsorption in the skin and the gut as they have more a1 adrenergic receptors

21
Q

how long does it take to restore blood volume after a haemorrhage

A

a few minutes only from redistribution of extracellular fluid

22
Q

what is another name for total body volume restoration

A

Renin Angiotensin Aldosterone System

23
Q

describe what happens in total body volume restoration

A

Reduced perfusion pressure (from a haemorrhage) stimulates the production of renin in the kidneys

The liver produces angiotensinogen

renin converts angiotensinogen to angiotensin 1 which is converted to angiotensin 2 which acts of the cardiovascular system to vasoconstrict

A2 also acts on the adrenal cortex to produce aldosterone which stimulates water and Na uptake in the kidney

24
Q

what is the overall effect of total body volume restoration

A

it stimulates Na and H2O reabsorption in the kidney which decreases urine output and therefore increases total body H2O

25
Q

Which statement is INCORRECT? An increase in
sympathetic nerve activity will :

A) Decrease heart rate

B) Increase venous return

C) Increase ventricular contractility

D) Increase the production of renin

A

A

26
Q

The baroreceptors are tonically inactive at rest

BECAUSE

at rest arterial blood
pressure is maintained at approximately 120/80 mmHg to silence the baroreceptors.

A

both statements are false

27
Q

Which of the following would decrease mean arterial blood pressure?

A: constriction of arterioles

B: dilation of arterioles

C: increased blood volume

D: increased peripheral resistance

A

B

28
Q

Information about blood pressure is collected and forwarded to the brain by the:

A: osmoreceptors

B: endothelial cells

C: chemoreceptors

D: baroreceptors

A

D

29
Q

Following donation of a unit of blood the total blood volume is decreased by 20% which results in a reduction in mean arterial blood pressure

BECAUSE

aortic and carotid baroreceptors are subject to lower levels of stretch.

A

the first statment is false but the second is true

30
Q

A decrease in mean arterial blood pressure will stimulate the nucleus tractus solitaris to decrease parasympathetic
nerve output to the heart and systemic arterioles

BECAUSE

the afferent nerve input into the nucleus tractus solitaris
is reduced by decreased mean arterial blood pressure.

A

the first statment is false and the second is true

PHSL 232 (30 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions