bp regulation & htn

Question 1

Difference in bp between a patients right and left arm is a sign of

Answer 1

vascular disease!

Question 2

Why is hypertension bad?

Answer 2

It damages blood vessels throughout the entire body, affecting multiple systems.

Ex) Heart, brain, renal failure, retinopathy, peripheral vascular disease

Question 3

Mechanisms of hypertension

Answer 3

• Chronic positive salt & water balance
  
  • _{Excessive salt; diseased kidney; messed up hormones; etc}
• Overactive nervous system sending signals to heart, kidney, and blood vessels to retain salt
• Incorrect responses of hormones that normally regulate salt and water balance & cardiovascular system
  
  • Increased heart contractility; vasoconstriction; decreased blood flow to kidney reducing salt excretion

Question 4

Most monogenetic causes of hypertension involves

Answer 4

Inappropriate Na+ reabsorption by the kidneys

_{Ex) Aldosteronism, liddle’s syndrome (excess Na+ channel activity), etc}

Question 5

Hypertension & Kidney disease can cause each other.

How does eating excessively salty food cause hypertension?

Answer 5

Eating too much salt can decrease your kidney’s Na⁺ excretory capability –> increased ECFV & BV

–> chronic increases in ECFV & BV or decreases in vascular capacitance will cause hypertension

Question 6

How does increased [NaCl] lead to concentrated urine and thirst?

Answer 6

ADH gets released –> thirst & concentrated urine

Whereas, if [NaCl] drops, then ADH gets inhibited.

Question 7

Osmolality is rapidly regulated by adjusting

Answer 7

the ECFV by peeing

Question 8

Salt-resistant patients

Answer 8

When they increase their salt intake, they do have increased cardiac output since their ECFV increases (like normal).

However, they have decreased vascular resistance to accommodate for this increased cardiac output –> won’t develop hypertension

Question 9

The most important regulatory mechanism of Na+ excretion is

Answer 9

GFR

• Autoregulatory mechanisms: higher bp, the greater afferent arteriole resistance to maintain RBF and GFR.
• NO from vascular smooth muscle cells maintains RBF and normal salt excretion

Question 10

What stimulates reabsorption at the proximal tubule?

Answer 10

Ang II

Adrenergic agents

Increased luminal flow or solute delivery

Question 11

What stimulates reabsorption at the thick ascending limb?

Answer 11

ADH

Adrenergic agents

Mineralcorticoids

Question 12

What diuretics work at the distal tubule and connecting tubule cells?

Answer 12

Thiazides block the Na/Cl cotransporter

Amiloride blocks the apical Na+ channels, and at higher concentrations, the Na/H exchanger

Question 13

What stimulates reabsorption at the collecting duct?

Answer 13

Aldosterone

Antidiuretic hormone

Question 14

Pressure natriuresis

Answer 14

The higher your blood pressure, the higher Na+ excretion.

However, whether your salt status (deplete or replete) determines how much Na you’ll excrete at any given pressure.

Question 15

The impact of nitric oxide on pressure natriuresis

Answer 15

It promotes sodium excretion when bp is high

Question 16

COX1 & 2 are constitutively expressed in the kidney.

What upregulates COX2?

Answer 16

• Volume restriction
• High renin states ( need to compensate)
  
  • Salt restriction
  • ACE inhibition
  • diuretic therapy
  • renovascular htn

Question 17

Giving an NSAID would have what effect on GFR and renal plasma flow?

Answer 17

Decreases both GFR & RBF because you don’t have prostaglandins to vasodilate. Thus, the RAS system is unopposed and going to vasoconstrict, decreasing both.

Question 18

ANP

Answer 18

• Vasodilates
• Decreases aldosterone, renin, and Na reabsorption

Question 19

Question 20

Beta blockers & calcium blockers

Answer 20

reduce blood vessel constriction

(remember that the sympathetic mechanism relies on norepi workign on a B receptor)