Cardiac EC Coupling & Calcium Handling II

Question 1

Norepinephrine released by sympathetic nerve terminals and circulating epinephrine act to 1

Answer 1

Increase Heart Rate (positive chronotropy) by raising the firing rate of pacemaker cells in the SA node.

Question 2

Norepinephrine released by sympathetic nerve terminals and circulating epinephrine act to 2

Answer 2

Increase Contractile Force (positive inotropy)

activation b-adrenergic receptors, elevation of cytoplasmic cAMP, and activation of Protein Kinase A (PKA).

Question 3

Norepinephrine released by sympathetic nerve terminals and circulating epinephrine act to 3

Answer 3

Increase Rate of Relaxation (positive lusitropy)

activation b-adrenergic receptors, elevation of cytoplasmic cAMP, and activation of Protein Kinase A (PKA).

Question 4

inotropy

Answer 4

an agent that alters the force or energy of muscular contractions. Negatively inotropic agents weaken the force of muscular contractions. Positively inotropic agents increase the strength of muscular contraction

Question 5

lusitropy

Answer 5

myocardial relaxation.

Question 6

Four important targets for Protein Kinase A (PKA) in cardiomyocytes are

Answer 6

The L-type Ca2+ channel
RyR2
Phospholamban (PLB)
Troponin

Question 7

L-type Ca2+ channel

Answer 7

Phosphorylation of the channel increases the amplitude of the L-type Ca2+ current, increasing

(i) the trigger for activation of RyR2 and over time
(ii) the SR Ca2+ content

Question 8

Phosphorylation causes PLB to dissociate from SERCA2, and thus _____________ , which speeds relaxation and increases SR Ca2+ content.

Answer 8

increases Ca2+ pumping into the SR

Question 9

long QT, which causes the heart muscle to take longer than usual to recharge between beats.

symptoms include immune deficiency and cognitive abnormalities.

Answer 9

Timothy Syndrome

Linked to de novo mutations in CaV1.2

Question 10

shortened Q-T interval
associated with a number of ECG alterations
linked to mutations of the cardiac sodium channel

Answer 10

Brugada Syndrome

Question 11

______ causes the heart muscle to take longer than usual to recharge between beats.

Answer 11

Prolonged QT syndrome

Question 12

do not display ECG abnormalities at rest, but do display abnormalities upon exercise or infusion of catecholamines.
dominant mutations in RyR2
b blockers are a standard therapy

Answer 12

Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT).

Question 13

debilitating disorder resulting in syncope, cardiac arrhythmias and sudden death.
patients display intermittent hypoglycemia, immune deficiency and cognitive abnormalities including autism.

Answer 13

Timothy Syndrome

Linked to de novo mutations in CaV1.2