Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

MBBS I CPRS > L44 – Roles of atrial stretch receptors, renin-angiotensin-aldosterone system (RAAS) and atrionatriuretic peptides (ANP) in the regulation of body compartment fluids > Flashcards

L44 – Roles of atrial stretch receptors, renin-angiotensin-aldosterone system (RAAS) and atrionatriuretic peptides (ANP) in the regulation of body compartment fluids Flashcards

(84 cards)

Start Studying
1
Q

What does the RAAS regulate?

A

Coordinates a variety of

physiological processes for proper regulation of blood volume and pressure

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

3 types of mechanisms for control of blood volume?

A

Neural
Hormonal
Neurohormonal

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

Which 2 types of blood volume control mechanisms share a common mechanism for blood volume detection?

A

Neural and Neurohormonal

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

Describe sequence of neural control of blood volume?

A

Receptor > afferent nerve > CNS > efferent nerve > effector organ or tissue

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

Describe sequence of hormonal control of blood volume?

A

Detection of change (e.g. atrial muscle stretch) > hormone release > blood circulation > effect on tissues

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

Describe sequence of neurohormonal control of blood volume?

A

Receptor > afferent nerve > CNS > hormone release AND efferent nerve > effector organ or tissue

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

Compare speed of response between 3 types of mechanisms for control of blood vol?

A 
Neural = immediate 
Neurohormonal = rapid onset 
Hormonal = slow onset
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Compare scale of effect between 3 mechanisms in blood vol. control?

A 
Neural = local 
Neurohormonal = Globlal 
Hormonal = global
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Compare duration of effect between 3 mechanisms in blood vol. control?

A 
Nerual = effect disappear immediately 
Neurohormonal = Long-lasting 
Hormonal = persist for hours
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

2 reasons for regulating blood volume?

A

Eliminate excess volume by urine formation> lower BP

Protect CVS from damage by large volume

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

2 ways blood volume is regulated?

A

By regulating water excretion and salt excretion

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

What is altered in regulation of water excretion?

A

Resorption of water from collecting duct

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

What alters regulation of salt excretion?

A

Renin-angiotensin- aldosterone system

Atrial natriuretic peptide (ANP)

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

How does salt excretion indirectly regulate water excretion?

A

Water follows salt due to osmotic gradient

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

What receptors detect rise in blood volume?

A

Atrial receptors - stretch receptors

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

Where are atrial receptors located?

A

Junctions of the vena cava with RA and pulmonary veins with LA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does increased blood volume cause increased firing of stretch receptors>?

A

Increased B.V. > increase Venous pressure > increase venous return > increase atrial filling > Stretch atrial wall > more firing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the functions of the L/R cardiac sympathetic nerves?

A

R. sym= regulate HR

L. sym= regulate contractility

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

What 2 reflexes make up Bainbridge reflex?

A

Increase R. cardiac sympathetic nerve activity

Decrease Renal sympathetic nerve activity

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

What other nerves respond in reflex to increased blood volume apart from Bainbridge reflex?

A

Decreased skeletal muscle and splanchnic circulation sympathetic activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the result of Decreased skeletal muscle and splanchnic circulation sympathetic activity ?

A

Decrease TPR > prevents large blood volume from increasing blood pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How is cardiac output controlled when blood volume is higher?

A

Increased BV > increase venous return > should increase stroke volume but increased R. cardiac sympathetic nerve activity = increase HR

Increase in HR causes decrease in stroke volume

CO = SV x HR

CO remains higher but under control
Prevent atria overstretch

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

How is BP related to changes in CO and TPR when blood volume is high? ( think which nerves are activated)

A

CO is higher (but under control)

Decreased sympathetic activity to splanchnic circulation and skeletal muscles = decrease TPR

BP = CO x TPR

Stable BP

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

In bainbridge reflex. Result of change in renal sympathetic activity on blood volume during high BV?

A

High BV > Decrease renal sympathetic activity > Allow renal AFFERENT arteriole to dilate > more blood enters capillaries > Increase glomerular capillary hydrostatic pressure > increase GFR > more urine production > lower BV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
How do atrial receptors and ADH regulate blood volume?
High B.V. > increase activity of atrial stretch receptor > afferent nerve to CNS > LOWER release of ADH from pituitary gland > less water reabsorption at collecting ducts > more urine production > Lower B.V.
26
What is Renin and Where is Renin secreted?
proteolytic enzyme: cleaves terminal section from angiotensinogen to form angiotensin I secretion from juxtaglomerular (JG) cells in afferent arteriole wall of kidney glomerulus
27
2 components of juxtaglomerular apparatus?
Juxtaglomerular cells + Macula Densa
28
What are JG cells' function?
JG cells: release renin, innervated by sympathetic nervous system
29
How does renin lead to formation of aldosterone ?
Angiotensinogen > (renin) > Angiotensin I > (ACE) > Angiotensin II > (adrenal cortex) > aldosterone
30
What is ACE? Found where?
Angiotensin converting enzyme At pulmonary capillary endothelial cell (and PCT)
31
Where is angiotensinogen made?
Liver (and PCT)
32
At cellular level, what 2 signals control renin release from JG cells?
cAMP and Ca2+
33
How do Ca and cAMP control renin release?
Increase intracellular cAMP = stimulate renin release Decrease intracellular Ca = inhibit renin release
34
How does increase intracellular Ca cause decrease renin release?
Increase intracellular Ca = inhibit adenyl cyclase 5 > inhibit formation of cAMP from ATP > lower intracellular cAMP conc. > less release of renin through PKC/ other ion channels
35
Why is calcium's role in renin regulation odd?
Only in kidney where increase calcium conc. doesnt lead to release of granules
36
What stimulates renin release?
Decrease in BP Decrease in GFR Renal sympathetic nerve activation Increase in Prostaglandins
37
How does Increase in BP stimulate renin release?
increase BP > increase afferent arteriole pressure > increase JG cell stretch (act as intrarenal baroreceptor) > depolarize JG > Ca2+ entry LOWERS cAMP > lower renin release > less vasoconstriction and water retention
38
What 2 things are proportional to GFR?
Macula densa intracellular Na (which regulates) ATP breakdown by Na/K-ATPase
39
What cell in distal tubule absorb Na?
Macula densa cell
40
What is the effect of increased GFR on Macula densa cells?
Increase GFR > increase NaCl delivered to and absorbed by Macula Densa > Increase macula densa intracellular Na = increase Na/K-ATPase activity > more ATP converted to adenosine
41
What is the effect of adenosine during high GFR?
Increase adenosine > vasoconstrict AFFERENT arteriole > reduce glomerular capillary pressure > GFR lowered + renin increase
42
What is the effect of low GFR on Macula densa cells and renin release?
Low GFR > less NaCl delivered to and absorbed by Macula Densa > lower intracellular NaCl > Activation of COX2 and PGE2 synthase > release of PGE2 to JG cell receptors > increase intracellular cAMP > increase renin secretion
43
How does Renin affect GFR and glomerular capillary pressure?
High Renin > angiotensin II > constrict renal blood vessels > efferent arteriole constrict more than afferent arteriole > Increase glomerular capillary pressure and increase GFR
44
Summarize the tubulo-glomerular feedback in high BP?
High BP > high GFR > low renin secretion > less angiotensin II > less constriction of renal blood vessels > lower Pgc and GFR
45
How does renal sympathetic nerve activation cause change in renin secretion?
Increase blood volume > Decrease renal sympathetic activity > less noradrenaline released > less B1 receptor stimulation on JG cells > less cAMP > less renin secretion
46
Explain what afferent arteriole prostacyclin secretions cause change in renin release?
1) Secrete NO, PGE2, PGI2 >> stimulate renin release at JG 2) Secrete Endothelins >>inhibit renin release at JG
47
4 effects of angiotensin II in body?
- Vasoconstrictor - Increase Sodium reabsorption at kidney -Act on brain and adrenal gland
48
Explain effects of angiotensin II on brain? e.g. during low BP
Increase BP by: | Increase thirst, salt appetite, ADH secretion
49
Explain effects of angiotensin II on adrenal gland?
Stimulate aldosterone synthesis for more Na absorption
50
How is BP related to angiotensin II levels?
high BP = low angiotensin II low BP = high angiotensin II level
51
Explain action of angiotensin II during Hypotension?
Low BP > low GFR > high renin > high angiotensin II > renal vasoconstriction (increase BP and TPR)
52
How does high angiotensin II change renal blood flow, glomerular capillary pressure and GFR?
Angiotensin II > efferent arteriole constrict more than afferent > lower renal blood flow, but higher Pgc and GFR Maintains adequate GFR despite decreased renal blood flow
53
Effect of angiotensin II at very low BP?
Widespread vasoconstriction throughout body
54
How does angiotensin II stimulate Sodium re-absorption at kidney?
 At apical membrane: stimulate: - Na/H exchanger in PCT - Epithelial Na channel (ENaC) in principal cells  At basolateral membrane: stimulate: - Na-HCO3 - cotransporter in intercalated cells - Na/K-ATPase
55
Explain the effects of angiotensin II on brain? (stimulate salt appetite, ADH release, thirst)
Angiotensin II cannot cross BBB > act on 3 circumventricular organs (Area Postrema, Subfornical Organ, Organum Vasculosum) > stiumulate other areas of brain for effects
56
How does angiotensin II affect aldosterone level?
Angiotensin II stimulates synthesis + release of aldosterone
57
What two things increase synthesis of aldosterone?
high K+ conc in ECF Angiotensin II
58
Where is aldosterone made?
Adrenal cortex
59
Explain action of aldosterone on Na+ levels?
Increase Aldosterone > increase activity of Na/K pump at distal tubule basolateral membrane > increase Na+ conc. gradient > more Na+ reabsorption
60
Explain action of aldosterone on K+ levels?
Increase Aldosterone > increase activity of Na/K pump at distal tubule basolateral membrane > increase K+ conc. gradient > more K+ excretion into filtrate
61
What channel does aldosterone increase in renal tubule?
aldosterone increases epithelial Na+ channel (ENaC) in collecting tubule to increase Na reabsorption
62
What ion is also excreted in Angiotesin II action on Na/K pump ?
increase Na reabsorption and increase K excretion > more H+ excreted into filtrate
63
Where are the components of intrarenal renin-angiotensin system made ?
JG = renin PCT = angiotensinogen + ACE AT 2 receptor made throughout kidney AT II made within kidney
64
How is brain RAS kept separate from systemic RAS?
due to BBB blocking angiotensin movement
65
Which angiotensin receptor is found in brain? Activated by which angiotensins?
AT I receptors activate by angiotensin II and III
66
What converts angiotensin I to III in brain RAS?
1 > 2 :ACE | 2 > 3: Aminopeptidase
67
4 effects of brain RAS?
increase sympathetic NS activity in CVS Increase ADH, thirst Modulate baroreflex sensitivity
68
Summarize effect on RAS by decreased blood volume?
Low BV = increase R,A,A Increase salt and water retention Blood volume increase to normal
69
What are the differences between AT 1 and AT2 receptors
AT1: vasoconstriction, sympathetic activation, Na+ and fluid retention AT2: Vasodilation, inhibit cell growth and apoptosis
70
Summarize effect on RAS by Increased blood volume?
Decrease R,A,A Less salt and water retention blood volume reduce to normal
71
How does salt retention result from heart failure ?
Heart failure > hypotention > reduce renal blood flow and GFR > increase renin > increase angiotensin II > increase vasoconstriction and salt reabsorption from kidneys > salt retention
72
How does high blood volume affect ANP level?
High BV > high BP > increase stretch of atrial muscle cells > release of secretory granules > more ANP released
73
Where does ANP act?
mainly on PCT to produce natriuresis (Na loss)
74
What is full name of ANP?
Atrial natriuretic peptide
75
4 actions of ANP in high BP?
Increase GFR decrease Na reabsorption Decrease renin secretion Inhibit effects of ADH
76
Explain effect of ANP on GFR?
High ANP > dilate AFFERENT arteriole > increase Pgc > increase GFR
77
Explain effect of ANP on salt reabsorption?
high BP > high ANP > inhibit action of angiotensin II on NHE > decrease Na reabsorption at PCT Inhibit epithelial Na channel > decrease Na reabsorption at late distal tubule and cortical collecting duct
78
How does ANP act on Epithelial Na Channel (ENaC)?
ANP > Natriuretic peptide receptor A > increase cGMP conc. > phosphorylate ENaC > decrease Na entry to PCT > decrease Na reabsorption
79
How does ANP affect ADH?
ANP reduces insertion of aquaporins into collecting ducts > decrease water reabsorption
80
How does ANP act on RAAS?
Act on JG to reduce renin secretion > less RAAS activation > less vasoconstriction, salt and water retention
81
What is BNP?
B-type natriuretic peptide
82
Where is BNP secreted?
Secreted by heart ventricles in response to excessive stretch
83
What is BNP a marker for?
marker for acute congestive heart failure, | hypertrophy
84
Compare BNP and ANP action?
 Binds to same receptors as ANP (ANPR A) with 10x lower affinity  Similar actions to ANP but much less effective

MBBS I CPRS (78 decks)

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