CVS

Question 1

spread of excitation between cells is allowed for by what?

Answer 1

Gap junctions.

Question 2

what are the steps involved in calcium induced calcium release?

Answer 2

1. AP enters from adjacent cell
2. VGCC (DHP receptor) open. allowing calcium entry.
3. calcium induces calcium release though ryanodine receptor channels. (RyR)
4. Local release causes calcium spark
5. Sum of calcium parks create a calcium signal.
6. calcium ions bind to troponin to initiate contraction
7. relaxation occurs when calcium unbinds from troponin
8. Calcium is pumped back into the sarcoplasmic reticulum for storage.
9. Calcium is exchanged with sodium.
10. sodium gradient is maintained by the sodium/potassium- ATPase.

Question 3

Name some DHP blockers?

Answer 3

Verapamil and Diltiazem are antagonists and channel blockers

Nifedipine is a DHP and acts as an antagonist. has a greater effect on vascular

Question 4

what do ryanodine receptors do?

Answer 4

located in the sarcoplasmic/endoplasmic reticulum membrane

responsible for the release of Ca2+ from intracellular stores during excitation-contraction coupling in both cardiac and skeletal muscle.

Question 5

What is an agonist to ryanodine receptors?

Answer 5

Ryanodine. binds to RyR2 receptor to cause calcium induced calcium release.

Question 6

What is an antagonist to Ryanodine receptors?

Answer 6

Dantrolene

Question 7

what noradrenaline do in the innervation of the heart?

Answer 7

acts upon sympathetic neurones to increase influx of NA+ and Ca2+. binds to B1 receptors of the autorhythmic cells. increased rate of depolarisation and thus increased heart rate.

Question 8

what does Acetylcholine do in the innervation of the heart?

Answer 8

Acts upon parasympathetic neurones and the muscarine receptors of the autorhythmic cells.
causes increased K+ efflux and decreased Ca2+ influx
Hyperpolarised and decreased rate of depolarisation leading to decreased heart rate.

Question 9

What type of receptor are adrenergic receptors?

Answer 9

G protein coupled receptors.

Question 10

propanolol is what?

Answer 10

Beta non specific antagonist

Question 11

what is phenylephrine?

Answer 11

Alpha 1 specific agonist

Question 12

Prazosin is what?

Answer 12

alpha specific antagonist. also an inverse agonist.

Question 13

what is an intropic effect?

Answer 13

where there is an alteration to the force or energy of muscular contractions

Question 14

what is a chronotropic effect?

Answer 14

effects that change the heart rate.

Question 15

what is the intropic effects of noradrenaline on the heart?

Answer 15

Increase contraction

Question 16

what can be used to increase peripheral resistance and blood pressure?

Answer 16

Noradrenaline

Question 17

How can hypertension be reduced?

Answer 17

Cardioactive drugs such as beta blocker Propanolol

drugs that relax arterial smooth muscle and reduce peripheral resistance such as dihydroprydines like Nifedipine.

Question 18

What is dihydropryridine?

Answer 18

antagonist of the V gated calcium channels on the vascular smooth muscle that can reduce peripheral resistance.

Question 19

what do beta blockers do?

Answer 19

reduce the sympathetic effects of Noradrenaline.

Question 20

what is angina?

Answer 20

is a transient ischemia of the heart muscle. the pain occurs when there is an inadequate cronary blood flow for the metabolic demands of the cardiac muscle.

Question 21

How is angina treated with organic nitrates?

Answer 21

Organic nitrates produce Nitric oxide
NO activates soluble guanylate cyclase that produces cGMP
cGMP activates protein kinase G.
PKG causes smooth muscle relaxation of the coronary artery allowing better perfusion.

Question 22

How does a heart attack happen?

Answer 22

cronary artery disease causes occlusion of the vessels. leads to reduced perfusion causing Ischemia and infarct. cells depolarise and die. can lead to dyrythsmias and heart faliure.

Question 23

what are pharmocological ways of preventing coronary heart disease?

Answer 23

Statins that reduce cholesterol synthesis.

Question 24

What are some of the acute treatments for coronary artery occlusion?

Answer 24

Clot busters (tissue plasminogen activator)
Physical interventions such as stenting

Question 25

Why are cardiac glycosides not used anymore for treating heart conditons?

Answer 25

very dangerous. if take wrong dose can kill very easily.