Regulation of Arterial Pressure

Question 1

Where is the vasoconstrictor area located?

Answer 1

bilateral in the upper medulla

Question 2

Where is the vasodilator area located?

Answer 2

lower medulla

Question 3

What is the functional mechanism of the vasodilator area of the VMC?

Answer 3

inhibits the vasoconstrictor area

Question 4

Where is the sensory area of the VMC located?

Answer 4

tractus solitaries

Question 5

What structures influence the VMC?

Answer 5

1) Reticular substance
     pons, di/mesencephalon
2) Hypothalamus
     postlateral = excitatory
     anterior = inhibitory
3) Cortex

Question 6

How does the sensory area of the VMC work?

Answer 6

innervated by vagus & glossopharyngeal reflexes, output to ANS.

Question 7

When does the ischemic response occur?

Answer 7

when BP < 60 mmHg

Question 8

What drives the ischemic resopnse?

Answer 8

metabolic/O2 lack in VMC

Question 9

where are baro-receptors located?

Answer 9

aorta & carotid arteries

Question 10

Describe the afferent pathway of the baroreflex?

Answer 10

vagal –> herrings –> glossopharyngeal

Question 11

what is the effector pathway for the baroreflex?

Answer 11

SNS to heart/vasculature

Question 12

What is the integrating center for the baroreflex?

Answer 12

VMC

Question 13

When does acute control of BP take place?

Answer 13

1) baroreflex

2) heavy exercise ==> 30% increase in MAP

Question 14

Describe the infinite feedback gain principle.

Answer 14

Indefinite increase in MAP –> indefinite increase in renal output

Question 15

When is kidney output 0?

Answer 15

below 60 mmHg

Question 16

What causes a long-term increase in BP?

Answer 16

1) Right-shift in RFC (decreased renal function)

2) Persistent change in salt/water intake

Question 17

What are the effects of AngII?

Answer 17

1) vasoconstriction
2) increased ADH
3) increased aldosterone
4) increased thirst
5) increased SNS activity

Question 18

What is the response to increased salt intake?

Answer 18

when ECT > 300 mOsm/L…

1) increased thirst
2) increased ADH

Question 19

Where is renin secreted?

Answer 19

JG cells of kidney

Question 20

When is renin secreted?

Answer 20

1) primary: response to decreased MAP, decreased V
2) also, decreased Na
3) also, beta-adrenergic activation

Question 21

How is AngII activated in the Renin-Angiotensin system?

Answer 21

1) renin secreted (peptidase)
2) angiotensinogen –> Ang1
- - Ang1 found in many tissues!
3) ACE: Ang1 - Ang2