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Flashcards in Arterial pressure regulation Deck (25):
1

which fibers terminate at the heart and vessels?

SNS and PNS postganglionic fibers

Efferent fibers

2

What is the afferent pathway of the baroreceptor reflex?

Sensory mechanoreceptors sense arterial pressure via stretch in arterial wall

*** Active at normal pressure means Tonic Signal

3

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

Increases it

4

Why are baroreceptors only good in the short term?

Adaptation
- continually elevated pressures can lead to gradual decrease in firing

5

Where do the parasympathetic fibers come from?

Nucleus ambiguus of medulla

6

Where do the sympathetic fibers come from?

1. Rostral ventrolateral medulla
2. Raphe nucleus of medulla

7

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

Enter medulla via nucleus tractus solitarius

8

What does a carotid message do?

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

Can fix some atrial tachyarrhythmias

9

What is the current theory of long term regulation?

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

10

How would increased arterial pressure affect urinary output rate?

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

11

How does one calculate the urinary output rate?

Glomerular filtration rate- renal fluid reabsorption rate?

12

What is significant of glomerular filtration?

Transcapillary fluid movement dependent on hydrostatic and onconic pressures!

13

What does most resorption in the kidneys follow?

Sodium
- Water follows Na+ via osmosis

14

What happens when we increase renal tubular Na+ reabsorption?

Increases water reabsorption and thus decreases urinary output

15

Where is angiotensinogen produced?

liver

16

What is RAAS?

Renin
Angiotensin
Aldosterone system

17

Where is renin produced and what is its purpose?

Kidneys
- Catalyzes conversion of angiotensiongen to angiotensin I

18

What converts Angiotensin I to angiotensin II?

Angiotensin converting enzyme (ACE)

19

What is the role of angiotensin II?

controls release of aldosterone

20

What is the role of aldosterone? Produced where?

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

Adrenal glands

21

what affects the release of Renin from kidneys?

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

What is another major affector of urine production?

Vasopressin (anti-diuretic hormone)

- release from post pituitary gland

23

whats the relationship between baroreceptors and ADH?

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

24

Where and how does ADH work?

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

Leads to increase water retention

25

What is a secondary function of ADH?

Vasoconstriction in severe hypovolemia via IP3 signal transduction pathway on VSM