Drug treatments for cardiovascular disease 1

Question 1

when is hypertension treated

Answer 1

Hypertension treatment if BP >150/95 mmHg

BP should be measured using ABPM or HBPM (persistently high)

Question 2

how should hypertension be treated

Answer 2

appropriate pharmacological treatment requires a knowledge of the physiological regulation of BP and a knowledge of how drugs work

Question 3

how is BP calculated

Answer 3

BP=COxTPR (total peripheral resistance)
CO=SVxHR
Reduce blood pressure so reduced stroke volume or strength of contraction
HR set by SA node
TPR is measured as degree of constriction of arterioles

Question 4

How is BP regulated sympathetically

Answer 4

dec CO
1
Dec aortic output
activate SNS
noradrenaline (arterioconstriction and inc afterload via a1-R or inc freq and force of contraction via B1-R)
2 
venules
inc preload via a1-R
inc freq and force of contraction via B1-R)

Question 5

How is the heart regulated extrinsically

Answer 5

SNS accelerates and PNS slows via the ANS (neural regulation of homeostasis)

Question 6

how do the PNS and SNS affect the heart

Answer 6

Sympathetic system increases frequency and force via b1 receptors to increase cAMP which increases Ca2+ to increases rate and force
Parasympathetic system decreases frequency by decreasing cAMP via M2 receptors

Question 7

how is TPR regulated

Answer 7

Regulation of TPR
SNS
SNS > NA > a1 > IP3 > Ca2+ > constriction

Question 8

what does RENIN do

Answer 8

turns angiotensinogen from the liver to Angiotensin I due to decrease in renal perfusion

Question 9

What does ACE do

Answer 9

Turns angiotensin I to angiotensin II

from the surface of pulmonary and renal endothelium

Question 10

what does angiotensin II do

Answer 10

Inc sympathetic activity
tubular Na+, Cl- reabsorption and K+ excretion and H20 retention
adrenal gland cortex - aldosterone secretion
arteriolar vasoconstriction, inc in BP
pituitary gland - ADH secretion leads to Collecting duct H20 absorption

Question 11

what does Angiotensin II do

Answer 11

Regulation in Ang II > increase IP3 > increase intracellular Ca2+
Causes constriction of arterioles and an increase in TPR and increase in BP

Question 12

how is preload regulated by RAAS

Answer 12

Constriction of venules via AT1-R

RAAS also facilitates Na+ and H20 retention

Question 13

What does aldosterone do to the aldosterone/sensitive distal nephron

Answer 13

Aldosterone activates cytoplasmic receptors which bind to the nucleus to increase expression of Na+ channels, aiding Na+ and water retention
Also increase Na+/K+ channel to maintain gradient

Question 14

How can hypertension be treated

Answer 14

Choice of drug dependant on
Age (<55 ACE inhibitor/angiotensin receptor blocker (ARB), >55 calcium channel blocker)
Race (ACE inhibitors/beta blockers may be less efficacious in black Africans/Americans)
Co-existing disease