Molecular cardiology

Question 1

Myocardial contraction/relaxation

Answer 1

Troponin - regulates actin/myosin/tropomysin - trop I provents actin/myosin complex - trop T tropomys binding, trop C releases CA from sarco reticulum
Tropomysin - regulates interaction of actin&myosin
Myosin - thick filament
Actin - attaches to myosin

Question 2

Bad remodeling

Answer 2

norepi
renin-angiotensin activation
endothelin-1
(dec'd NO, inc'd collagen/fibrosis, cellular apoptosis)
argine-vasopressin

Question 3

Good remodeling

Answer 3

ACEi reduce endothelin by reducing angiotensin

Naturetic peptides vasodilate and prevent myocyte hypertrophy (atrial naturetic peptide)

Question 4

ASA

Answer 4

inibits plt activation by COX=1 inhibition irreversibly

Question 5

P2Y12s

Answer 5

P2Y12 ADP receptor inhibition (plavix, prasugrel, ticagrolor)

Question 6

IIb/IIIa

Answer 6

eptifibide, abciximab, tirofiban

Question 7

Bivalirudin

Answer 7

Direct thormbin inhibitor

Question 8

Heparin

Answer 8

inhibit anti-thrombin III

Question 9

Excitation contraction coupling

Answer 9

Extracell Ca+ enters cell
release of Ca+ from sarcoplastic reticulum (ryanodine receptors)
Ca+ binds trop C
conformation change displace tropomyosin from actin binding site
cross bridge myosin and actin
Power stroke (movement of myosin heads along actin filament
ATP binding needed for myosin release from actin filament (myocardial relaxation is ATP dependent)
Cycle continues till Ca low enough conc in cell that dissociates from trop C -> returns original conformation of tropomyosin so it again blocks myosin from from accessing actin binding sites