Arterial pressure regulation Flashcards

1
Q

which fibers terminate at the heart and vessels?

A

SNS and PNS postganglionic fibers

Efferent fibers

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2
Q

What is the afferent pathway of the baroreceptor reflex?

A

Sensory mechanoreceptors sense arterial pressure via stretch in arterial wall

*** Active at normal pressure means Tonic Signal

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3
Q

Increasing stretch does what to AP generation on the baroreceptor reflex?

A

Increases it

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4
Q

Why are baroreceptors only good in the short term?

A

Adaptation

- continually elevated pressures can lead to gradual decrease in firing

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5
Q

Where do the parasympathetic fibers come from?

A

Nucleus ambiguus of medulla

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6
Q

Where do the sympathetic fibers come from?

A
  1. Rostral ventrolateral medulla

2. Raphe nucleus of medulla

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7
Q

How do the afferent fibers of the baroreceptor reflex enter the brain?

A

Enter medulla via nucleus tractus solitarius

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8
Q

What does a carotid message do?

A

increases pressure in carotid sinus to trick body into increasing parasympathetics to decrease pressure!

Can fix some atrial tachyarrhythmias

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9
Q

What is the current theory of long term regulation?

A

Long term pressure regulation crucially involves the kidneys, their NA+ handling and ultimately the regulation of blood volume

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10
Q

How would increased arterial pressure affect urinary output rate?

A

Increases it and thus decreases fluid volume, CO and later decreases arterial pressure

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11
Q

How does one calculate the urinary output rate?

A

Glomerular filtration rate- renal fluid reabsorption rate?

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12
Q

What is significant of glomerular filtration?

A

Transcapillary fluid movement dependent on hydrostatic and onconic pressures!

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13
Q

What does most resorption in the kidneys follow?

A

Sodium

- Water follows Na+ via osmosis

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14
Q

What happens when we increase renal tubular Na+ reabsorption?

A

Increases water reabsorption and thus decreases urinary output

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15
Q

Where is angiotensinogen produced?

A

liver

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16
Q

What is RAAS?

A

Renin
Angiotensin
Aldosterone system

17
Q

Where is renin produced and what is its purpose?

A

Kidneys

- Catalyzes conversion of angiotensiongen to angiotensin I

18
Q

What converts Angiotensin I to angiotensin II?

A

Angiotensin converting enzyme (ACE)

19
Q

What is the role of angiotensin II?

A

controls release of aldosterone

20
Q

What is the role of aldosterone? Produced where?

A

primary regulator of rate of Na+ reabsorption by renal tubular cells

Adrenal glands

21
Q

what affects the release of Renin from kidneys?

A
  1. Increase in renal sympathetics
  2. lowered glomerular filtration rate
  3. activation of sympathetics vasoconstrictor nerves in renal arterioles

increase in all causes increase Renin and increased Na+ reabsorption and thus decrease urinary output

22
Q

What is another major affector of urine production?

A

Vasopressin (anti-diuretic hormone)

  • release from post pituitary gland
23
Q

whats the relationship between baroreceptors and ADH?

A

Increased afferent input from baroreceptors means decreased release of ADH and less water retention

24
Q

Where and how does ADH work?

A

On renal collecting ducts via V2 receptors to increased water perm (cAMP dependent)

Leads to increase water retention

25
Q

What is a secondary function of ADH?

A

Vasoconstriction in severe hypovolemia via IP3 signal transduction pathway on VSM