Cardiovascular 2

Question 1

Hypertension:

Answer 1

Chronically elevated arterial BP

Question 2

How are HTN and atherosclerosis related?

Answer 2

HTN contributes to atherosclerosis, which interferes with endothelia, worsening HTN.

Question 3

Primary HTN:

Answer 3

• Etiology unknown
• 90~95% cases
• Tx aimed at directly lowering BP

Question 4

Secondary HTN:

Answer 4

Results from identifiable underlying causes (3~5% renal, 2~5% endocrine, congenital aortic narrowing), permanent cures targeting underlying cause are more effective.

Question 5

Normal BP

Answer 5

Systolic < 120 AND

Diastolic < 80

Question 6

Elevated BP

Answer 6

Systolic 120-129 AND

Diastolic <80

Question 7

Stage 1 HTN

Answer 7

Systolic 130-139 OR
Diastolic 80-89
Most common, therefore most deaths occur in this category

Question 8

Stage 2 HTN

Answer 8

Systolic > 140 OR

Diastolic > 90

Question 9

Hypertensive crisis

Answer 9

Systolic > 180 AND/OR

Diastolic > 120

Question 10

How do the heart & vasculature contribute to HTN?

Answer 10

(1) Excessive responsiveness to catecholamines (i.e. SNS) generally increases vasoconstriction, leading to increased HR, SV & TPR.
(2) Loss of local vasodilators such as NO (occurs w/ atherosclerosis)
(3) Excessive production of vasoconstrictors (eg: endothelin-1). Associated with injury and blood clotting (so likely to be common in vessels that are affected by atherosclerosis.
(4) Ion channel defects affecting both vasoconstriction and cardiac function
(5) Structural defects in heart or blood vessels

Question 11

How does the SNS activation measured?

Answer 11

Plasma epinephrine levels

Question 12

How does the nervous system contribute to HTN?

Answer 12

• Increased SNS activity

- Desensitized baroreceptors and volume receptors (esp. w/long-term high BP) or abnormal response to their signals.

Question 13

How does the SNS contribute to HTN?

Answer 13

• Increased baseline SNS activity

- Abnormally high stress response

Question 14

Pressure diuresis

Answer 14

In a normally functioning kidney, increased blood pressure (like from high fluid consumption) should increase urine production.

Question 15

From an evolutionary perspective, the kidney is designed for…

Answer 15

Our Paleozoic ancestors who ate less Na+ and more K+

Question 16

When excess salt is consumed…

Answer 16

Plasma osmolarity increases, triggering ADH release and causing water retention and more concentrated urine. In the absence of aldosterone, there is a net Na+ loss. This is usually enough to prevent changes in BP.

Question 17

Pressure natriuresis kicks in when…

Answer 17

ADH response is not enough to prevent increased blood pressure. Elevations in renal perfusion pressure (RPP) inhibits Na+ reabsorption in the tubule, increasing sodium excretion.

Question 18

Pressure natriuresis is __________ on neural or endocrine factors.

Answer 18

not dependent

*however, neural and endocrine factors (e.g. renin and ANP) can MAGNIFY it

Question 19

Angiotensin _____ pressure natriuresis,

Answer 19

inhibits

Question 20

ANP _____ pressure natriuresis.

Answer 20

augments

Question 21

Pressure natriuresis

Answer 21

When BP rises, Na+ and H2O are excreted until blood volume is lowered enough to reduce BP intake to normal.