long term control of bp (15)

Question 1

what value classifies hypotension?

Answer 1

systolic below 90 mmHg

Question 2

what value classifies hypertension

Answer 2

condition sustained elevation & arterial pressure 140/90

Question 3

list some factors that could cause transient elevations in blood pressure

Answer 3

Transient elevations are normal and can be caused by fever, physical exertion and emotional upset.

Question 4

what is the “fast acting” response to changes in arterial blood pressure?

Answer 4

Baroreceptors reflex- cardiac and vascular changes in vascular tone and transmits through sympathetic tone and changing vascular resistance

Question 5

what is the “intermediate acting” response to changes in arterial blood pressure?

Answer 5

renal actions

Question 6

what is the “slow acting” response to changes in arterial blood pressure?

Answer 6

Renal salt & water excretion

Chronic regulation of volume main hormone: angiotension II

Question 7

what is the macula densa?

Answer 7

specialized group of epithelial cells in the initial portion of distal tubules

Question 8

where in the kidney is renin produced?

Answer 8

in the juxtaglomerular apparatus

Question 9

tell me about the mesangial cells

Answer 9

provide anchor, may be involved in response to hypotension as certain actin + myosin and may act under sympathetic stimulation

Question 10

where is the JGA located?

Answer 10

located at the junction of afferent arteriole, ascending limb of PCT and DCT

Question 11

what are the 3 determinants of renin secretion?

Answer 11

1. Neural baroreceptors signal via renal sympathetics to granular cells in JGA
2. Intra-renal baroreceptors in afferent arterioles (granular cells)
3. Sodium chloride delivery to macula densa of JGA

Question 12

tell me 4 functions of angio II

Answer 12

1. A powerful vasoconstrictor- increases vascular resistance
2. Constricts mesangial cells- reduce GFR
3. Stimulates secretion of Aldosterone
4. Acts as negative feedback to inhibit rennin production on granular cells

Question 13

what are two minor factors (besides angio II) that affect aldosterone secretion?

Answer 13

plasma K concentration

ANP

Question 14

tell me about the “tubuloglomerular feedback”

Answer 14

Acts In the opposite direction to other reflexes in order to blunt effectiveness and prevent “over correction”.

Question 15

what is the effect of ANP?

Answer 15

Inhibit release of rennin, relax afferent arteriole

Question 16

what effect do the following have on Na reabsorption?
cortisol
estrogen
glucagon
progesterone

Answer 16

cortisol- increase
estrogen- increase
glucagon- decrease
progesterone-decrease

Question 17

what effect do the following have on Na reabsorption?
PTH
growth hormone
thyroid hormone
insulin

Answer 17

PTH- decrease
growth hormone- increase
thyroid hormone- increase
insulin-increase

Question 18

tell me about an instance when baroreceptors & osmoreceptors act in conflict. who wins?

Answer 18

Bp starts dropping—body increase ADH release, water reabsorption.. but that will decrase osmolarity and that acts to decrease ADH release. BUT it is always volume that wins- and the person will sacrifice being hypo-osmotic in order to keep blood volume up

Question 19

what hormone primarily controls sodium levels?

Answer 19

aldosterone

Question 20

what is guyton’s hypothesis for why hypertension occurs

Answer 20

abnormal renal sodium handling is the pathogenesis of HTN

Question 21

tell me about how obesity can lead to high bp

Answer 21

Obesity→ insulin resistance→ hyperinsulinemia→ increased SNS activity on vessels & heart → increased vasoconstriction & cardiac output both which lead to high BP.

hyperinsulinemia–>vasoconstriction

hyperinsulinemia–> acts on kidney to increase Na reabsorption–> increased BP