Cardio muscle phys Flashcards Preview

S&F III: Exam 1 > Cardio muscle phys > Flashcards

Flashcards in Cardio muscle phys Deck (19):
1

effective refractory period (absolute)

phase 0-3, no action potential generated

2

fast response action potential

occurs in atrial and ventricular cells

3

frank starling law

increasing length of sarcomere increases force of contraction

4

funny current (If)

Na current that initiates AP in pacemaker cell

5

phospholamben

protein in SR that regulates CA uptake by SR

6

preload

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

7

relative refractory periord

phases 3-4, longer time for AP

8

slow response action potential

occurs in pacemaker cells

NO PLATEAU, NO EXTERNAL SIGNAL

9

Phase 4 (FRAP)

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

10

phase 0 (FRAP)

fast NA+ channels open briefly

11

phase 1 (FRAP)

partial repol; efflux of K+; inactivation of Na

12

phase 2 (FRAP)

CA LTYPE OPEN, balance of K and CA

"plateau"

13

phase 3 (FRAP)

K+ efflux>>>>>>Ca influx; REPOL

14

phase 4 (FRAP)

ion normal; Na removed by NA-CA exchange

15

SRAP specialness

resting potential less negative--> NO FAST NA
NO PHASE 1&2

16

Phase 0 (SRAP)

less rapid, depends on both L and T Ca channels

17

Phase 4 (SRAP)

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

18

Contraction mechanism

calcium binds troponin C, changes tropomysosin, actin unblocked

19

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

disruption of myocardial fibers