Biochemistry

Question 0

Ventricular action potential

Answer 0

Phase 0 I na rapid depolarization 
Phase 1 Ito slow depolarization 
Phase 2 Ica, I na,Iks plateau 
Phase 3 Ikr.  Repolarization 
Phase 4 resting  na, k reset

Question 1

Impulse propagation

Answer 1

Done at -60mv

Question 2

Drugs and effects

Answer 2

Class 1a sodium channel lengthen action potential
Class 1b sodium shorten action potential
Class 2 beta blockers none - decrease automaticity
Class 3 potassium channel lengthen AP
Class 4 ca blockers - L type lengthen AP decrease automaticity
Dig sod pot exchange lengthen AP
Adenosine pot channel shorten AP

Question 3

Heaet failure chemistry

Answer 3

SERCA dysfunction
Increase intra cellular calcium
Compensatory beta receptor down regulation
Met result poor calcium flux

Question 4

EC coupling

Answer 4

Bridge between ASAP and contraction
Control calcium and control the system
Hyper phosphorylation and calcium leak occur in CHF.
It costs ATP to relax

Question 5

AT2 effects

Answer 5

Vasoconstriction 
Sodium retention 
Sympathetic activation
Endothelial dysfunction 
Atherosclerosis 
LVH and fibrosis

Question 6

Sympathetic system

Answer 6

Alpha1 vasoconstriction
Alpha2 vasorelaxation NE release
Beta1 myocardial contraction
Beta 2 vasorelaxation

Question 7

G protein

Answer 7

G as ionotrophy and chronotrophy in the heart and vasorelaxation in the periphery

G ai negative chronotrophy and ionotrophy

G aq peripheral vasoconstriction

Question 8

Beta2 coupled with Gs
Activates AC cyclic amp in obits mlck in smooth muscle
Causes vaso dilatation

Answer 8

Alpha 1 coupled with Gq activates PLC and IP3 releases calcium and vasoconstriction

Question 9

Alpha2

Answer 9

Inhibits norepinephrine release and vaso dilatation

Question 10

Agonists
Epi alpha1 beta1 beta2 increase chronotrophy and ionotropy of heart
Vasodilation in low dose and vasoconstriction in high dose

Nor epi alpha 1 and beta 1 heart increase chronotropy and ionotropy
Peripheral vasoconstriction

Answer 10

Dibutamine beta1 beta2 increase chronotropy and ionotropy and peripheral vaso dilatation

Phenyl ephrinre alpha 1 vasoconstriction
Clonidine alpha2 vaso dilatation

Question 11

Parasympathetic M3 receptor coupled with Gq activates pLc/ip3 release calcium and vadoconstricbb

Acetylene choline intact endothelium cause NO release and relaxation but denuded endothelium reacts with Gq/Plc and releases calcium and coronary spasm

Answer 11

Parasympathetic opposes beta 1

Question 12

Mixed venous

Answer 12

75% high output