MM <3 regulators Flashcards

1
Q

Only the ___ plateaus during exercise (cardiac output)

A

SV

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2
Q

The heart and vasculature are regulated, in part, by:

A

neural (autonomic)

humoral (circulating or hormonal) factors.

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3
Q

Neural mechanisms involve ______________ branches of the autonomic nervous system.

A

sympathetic adrenergic & parasympathetic cholinergic

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4
Q

In general, the sympathetic system stimulates the heart and constricts blood vessels resulting in a rise in arterial pressure.

The parasympathetic system depresses cardiac function and ___________

A

dilates selected vascular bed

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5
Q

There are several very important humoral mechanisms including __________________ (6) . Each of these humoral systems directly or indirectly alter cardiac function, vascular function, and arterial pressure.

A
circulating catecholamines
the renin-angiotensin system
 vasopressin (antidiuretic hormone)
atrial natriuretic peptide,
 endothelin
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6
Q

The medulla, located in the brainstem above the spinal cord, is a major site in the brain for regulating____________________, and is particularly important for short-term feedback regulation of arterial pressure.

A

outflow to the heart and blood vessels

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7
Q

The _______________ (NTS) of the medulla receives sensory input from different systemic and central receptors (e.g., baroreceptors and chemoreceptors).

A

nucleus tractus solitarius

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8
Q

In general, the sympathetic system stimulates the heart and constricts blood vessels resulting in a rise in _________.

The parasympathetic system depresses cardiac function and dilates selected vascular bed

A

arterial pressure

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9
Q

The nucleus tractus solitarius (NTS) of the medulla receives sensory input from different systemic and central receptors (e.g., ____________).

A

baroreceptors

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10
Q

The heart is innervated by vagal and sympathetic fibers. The right vagus nerve primarily innervates the _______ node, whereas the left vagus innervates the AV node

A

SA node

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11
Q

Sympathetic effects on heart function are mediated by beta-adrenoceptors

parasympathetic effects on heart function are mediated by _____________

A

muscarinic receptors

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12
Q

The release of acetylcholine (ACh) from parasympathetic nerves binds to muscarinic ACh receptors, has a direct ________ action (coupled to nitric oxide formation and guanylyl cyclase activation).

A

vasodilatory

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13
Q

The heart is innervated by vagal and sympathetic fibers. The right vagus nerve primarily innervates the SA node, whereas the left vagus innervates the _________ node

A

AV Node

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14
Q

Sympathetic effects on heart function are mediated by ______________

parasympathetic effects on heart function are mediated by muscarinic receptors

A

beta-adrenoceptors

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15
Q

Circulating catecholamines are?

A

epinephrine and norepinephrine

important humoral mechanisms

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16
Q

Epinephrine is released by the __________ upon activation of preganglionic sympathe`tic nerves innervating this tissue.

A

adrenal medulla

This activation occurs during times of stress

17
Q

Norepinephrine is also released by the adrenal medulla (about 20% of its total catecholamine release is norepinephrine).

The primary source of circulating norepinephrine is spillover from ____________ innervating blood vessels.

A

sympathetic nerves

18
Q

Circulating Epinephrine Causes:

A

Increased heart rate and inotropy (β1-adrenoceptor mediated)

Vasoconstriction in most systemic arteries and veins (postjunctional α 1 and α 2 adrenoceptors)

19
Q

Circulating Norepinephrine Causes`

A

Increased heart rate (although only transiently) and increased inotropy (β1-adrenoceptor mediated) are the direct effects norepinephrine on the heart.
Vasoconstriction occurs in most systemic arteries and veins (postjunctional α 1 and α 2 adrenoceptors)

20
Q

Overall CV response to epinephrine is increased _________ and a small change in mean arterial pressure.

A

Cardiac Output

21
Q

The overall cardiovascular response to Circulating Norepinephrine is increased cardiac output and systemic vascular resistance, which results in an elevation in __________

A

arterial blood pressure.

22
Q

Because catecholamines act on the heart and blood vessels through alpha and beta adrenoceptors, the cardiovascular actions of catecholamines can be blocked by treatment with ______________

A

alpha-blockers and beta-blockers

23
Q

The renin-angiotensin-aldosterone system (RAAS) plays an important role in regulating blood volume and systemic vascular resistance, which together influence:

A

cardiac output and arterial pressure

24
Q

Renin, released by the kidneys, stimulates the formation of angiotensin in blood and tissues, which in turn stimulates the release of ____________ from ___________.

A

aldosterone from the adrenal cortex

25
Q

Renin is a proteolytic enzyme that is released into the circulation primarily by the kidneys. Its release is stimulated by:

A

1- sympathetic nerve activation (β1-adrenoceptors)
2- renal artery hypotension
3- decreased sodium delivery to the distal tubules of the kidney.

26
Q

Vascular endothelium has an enzyme, angiotensin converting enzyme (ACE), that cleaves off 2 aa to form _______ from AI

A

angiotensin II (AII)

27
Q

angiotensin II (AII) functions to:

A

1- Constricts vessels—> increasing systemic vascular resistance and arterial pressure

2- release aldosterone (adrenal cortex), which in turn acts on the kidneys to increase sodium/fluid retention

3- Stimulates the release of vasopressin (antidiuretic hormone, ADH)

4- Facilitates norepinephrine release from sympathetic nerves

5- Stimulates cardiac hypertrophy and vascular hypertrophy

28
Q

The renin-angiotensin-aldosterone pathway regulated by the mechanisms that stimulate renin release, & also modulated by ___________ released by the heart. These act as an important counter-regulatory system.

A

natriuretic peptides (ANP and BNP)

29
Q

The main physiological actions of natriuretic peptides ((ANP and BNP) ) is to reduce arterial pressure by ______________

A

decreasing blood volume and systemic vascular resistance.

30
Q

__________ is a peptide hormone formed in the hypothalamus. Its two primary functions are to retain water in the body and to constrict blood vessels

A

Vasopressin (aka Argipressin)

31
Q

Mechanisms regulating the release of Vasopressin

A

Hypovolemia
Hypotension
Hypothalamic
Dehydration

32
Q

cardiopulmonary baroreceptors entering the atria decrease their firing rate when there is a fall in atrial pressure. Nerve fibers from these receptors synapse within the medulla, which signals to hypothalamus for A_________ by the pituitary

A

Vasopressin (aka Argipressin) release

33
Q

Hypotension, which decreases arterial ____________, leads to enhanced sympathetic activity that increases AVP release

A

baroreceptor firing

34
Q

___________ located in a region of the hypothalamus regulate AVP release.

A

Angiotensin II receptors

an increase in angiotensin II simulates AVP release.

35
Q
Natriuretic peptides (ANP and BNP) is cause decrease renin release, thereby decreasing circulating levels of \_\_\_\_\_\_. 
This leads to natriuresis and diuresis.
A

angiotensin II and aldosterone

36
Q

Taken together, the actions of NPs decrease:

A
↓ blood volume
↓ arterial pressure
↓ central venous pressure
↓ pulmonary capillary wedge pressure
↓ cardiac output.
37
Q

Natriuretic peptides serve as a counter-regulatory system for the ______ system.

A

renin-angiotensin-aldosterone