cardiac meds

Question 1

cardiovascular controls

(3 marks)

Answer 1

• autonomic nervous system
• hormones
• kidney and fluid balance mechanisms

Question 2

autonomic nervous system split into?

(2 marks)

Answer 2

sympathetic nervous system
parasympathetic nervous system

Question 3

when is the sympathetic nervous system initated and what happens?

(5 marks)

Answer 3

• initiated in ‘fight or flight’ situations
• norepinephrin released at neuromuscular junctions in heart, blood vessels and adrenal glands
• increases stroke volume which causes peripheral vasoconstriction. stimulates adrenaline release.
• increases HR and arteriole change

Question 4

when is the parasympathetic nervous system initated and what happens?

(2 marks)

Answer 4

• ‘rest and digest’
• acetylcholine released at heart - slows HR

Question 5

hormonal controls?

(3 marks)

Answer 5

• vasoconstriction
• vasodilation
• altering blood volume

Question 6

where is adrenaline and noradrenaline produced?

(1 mark)

Answer 6

adrenal medulla

Question 7

where is renin-angiotensin (system) controlled/produced?

(1 mark)

Answer 7

kidney

Question 8

where is aldosterone produced?

(1 mark)

Answer 8

adrenal cortex

Question 9

where is antidiuretic hormone produced?

(1 mark)

Answer 9

posterior pituitary

Question 10

what does aldosterone do?

(4 marks)

Answer 10

• acts on DCT and collecting duct
• = reabsorption of water
• (involves exchange of Na and K -
• leading to loss of K+ and retention of Na+)

Question 11

what does ADH do?

(3 marks)

Answer 11

• acts on collecting duct
• = increase permeability of H20 -
• increases water retention

Question 12

modes of action of cardiovascular drugs?

(4 marks)

Answer 12

• increase contractile strength - positive ionotropes
• alter HR - chronotropes (+/-)
• improve peripheral circulation - vasodilation, correct fluid balance
• protect against arrthymias

Question 13

what are the contractile agents?

(3 marks)

Answer 13

• glycosides
• calcium sensitisers
• xanthiane derivatives

Question 14

pharmacodynamics of glycosides?

(4 marks)

Answer 14

• increases calcium stored in vesicles in muscle fibres
• this occurs indirectly via inhibition of myocardial Na-K ATPase enzyme
• more calcium exposes more binding sites for myosin, producing more forceful contraction.
• inhibiton of Na-K ATPase leads to increase in intracellular sodium and (indirectly) calcium

Question 15

safety margin of glycosides?

(1 mark)

Answer 15

narrow safety margin between therapeutic and side effects

Question 16

example of a glycoside?

(1 mark)

Answer 16

digoxin

Question 17

side effects of glycoside?

(seen in overdose)

(4 marks)

Answer 17

• V++ and anorexia
• life threating arrthymias-
• (hypokalaemia increases risk of arrthymia)
• some dieuretics cause K+ loss

Question 18

pharmacodynamics of calcium sensitisers?

(3 marks)

Answer 18

• enhance existing intracellular calcium on myosin binding sites
• vasodilatory action through calcium effect on vascular smooth muscle.
• mild chronotropic effect

Question 19

side effect of calcium sensitisers?

(1 mark)

Answer 19

V++

Question 20

example of calcium sensitiser?

(1 mark)

Answer 20

pimobendan