Cardio muscle phys

Question 1

effective refractory period (absolute)

Answer 1

phase 0-3, no action potential generated

Question 2

fast response action potential

Answer 2

occurs in atrial and ventricular cells

Question 3

frank starling law

Answer 3

increasing length of sarcomere increases force of contraction

Question 4

funny current (If)

Answer 4

Na current that initiates AP in pacemaker cell

Question 5

phospholamben

Answer 5

protein in SR that regulates CA uptake by SR

Question 6

preload

Answer 6

increased stretching of cardiac muscle prior to contraction (increased SV, EDV)

Question 7

relative refractory periord

Answer 7

phases 3-4, longer time for AP

Question 8

slow response action potential

Answer 8

occurs in pacemaker cells

NO PLATEAU, NO EXTERNAL SIGNAL

Question 9

Phase 4 (FRAP)

Answer 9

K+ channels open, resting potential, K+>IC; Na>EC

Question 10

phase 0 (FRAP)

Answer 10

fast NA+ channels open briefly

Question 11

phase 1 (FRAP)

Answer 11

partial repol; efflux of K+; inactivation of Na

Question 12

phase 2 (FRAP)

Answer 12

CA LTYPE OPEN, balance of K and CA

“plateau”

Question 13

phase 3 (FRAP)

Answer 13

K+ efflux»»»Ca influx; REPOL

Question 14

phase 4 (FRAP)

Answer 14

ion normal; Na removed by NA-CA exchange

Question 15

SRAP specialness

Answer 15

resting potential less negative–> NO FAST NA

NO PHASE 1&2

Question 16

Phase 0 (SRAP)

Answer 16

less rapid, depends on both L and T Ca channels

Question 17

Phase 4 (SRAP)

Answer 17

spontaneous gradual depolarization due to slow NA influx (“funny current”)

Question 18

Contraction mechanism

Answer 18

calcium binds troponin C, changes tropomysosin, actin unblocked

Question 19

whats decrease in tension at high degress of stretch due to?

Answer 19

disruption of myocardial fibers