Phys 9

Front 1

Three types of cardiac muscle

Back 1

atrial, ventricular, and excititory/conductive fibers

Front 2

Duration of cardiac muscle contraction compared to skeletal muscle

Back 2

much longer in cardiac

Front 3

Cardiac muscle arrangment

Back 3

latticework of cells connected in series and parallel

Front 4

intercalated discs

Back 4

cell membranes that separate cardiac cells (contain gap junctions)

Front 5

average V of AP in ventricular muscle fiber

Back 5

105 mV (from -85 to +20)

Front 6

time ventricular cells remain depolarized

Back 6

0.2 seconds

Front 7

Channels that cause cardiac AP

Back 7

1)Fast sodium channels (also in skeletal muscle) 2) Slow calcium channels

Front 8

After onset of AP, how much does K+ permeability change

Back 8

decreases 5 fold

Front 9

velocity of AP across atrial and ventricular muscle fibers

Back 9

0.3 to 0.5 m/s (1/250 the speed of nerve fibers and 1/10 of skeletal muscle)

Front 10

Purkinje fiber AP velocity

Back 10

as much as 4 m/s

Front 11

Normal ventricular refractory period

Back 11

0.25 to 0.3 s

Front 12

Normal atrial refractory period

Back 12

0.15 s

Front 13

Skeletal vs. cardiac sarcoplasmic reticulum

Back 13

cadiac is less developed (Ca stored in T tubules)

Front 14

What keeps Ca in T tubules

Back 14

eletronegatively charged mucopolysaccarides

Front 15

What is T tubule Ca concentration dependent on

Back 15

extracellular fluid Ca concentration

Front 16

Legth of AP delay from atria to ventricles

Back 16

0.1 s

Front 17

P wave cause

Back 17

spread of depolarization through atria

Front 18

QRS wave cause

Back 18

depolarization of ventricles (about .16 s after P wave onset)

Front 19

T wave

Back 19

repolarization of ventricles

Front 20

acute sign of heart failure

Back 20

SOB

Front 21

pressure changes in atria - a wave

Back 21

atrial contraction

Front 22

pressure changes in atria - c wave

Back 22

ventricles contract (slight backflow and valves bulging backwards)

Front 23

pressure changes in atria - v wave

Back 23

slow flow of blood into atria while valves closed

Front 24

First third of diastole

Back 24

rapid filling of ventricles

Front 25

Last third of diastole

Back 25

atria contract (additional 20 percent ventricular filling)

Front 26

Isometric/Isovolumic contration in ventricles

Back 26

Beginning of systole before valves (aortic and pulmonary) open

Front 27

Isometric/Isovolumic relaxation in ventricles

Back 27

beginning of diastole before atrioventricular values open

Front 28

End systolic volume and end diastolic volume

Back 28

40-50 mL and 110-120 mL

Front 29

papillary muscle

Back 29

pull valve toward ventricles to prevent bulging too far backwards

Front 30

volume-pressure work/external work

Back 30

move blood from low pressure veins to high pressure arteries (major proportion of E)

Front 31

kinetic energy of blood flow

Back 31

accelerate blood to its velocity of ejection (minor proportion of E)

Front 32

What happens to systolic pressure with a fill V of over 150-170mmHg

Back 32

decreases-actin and myosin filaments are pulled far enough apart that the strength of each contraction becomes less than optimal

Front 33

maximum systolic right and left ventricular pressure

Back 33

right = 60-80mmHg; left = 250-300mmHg

Front 34

Preload

Back 34

degree of tension on muscle when it begins to contract

Front 35

Afterload

Back 35

load against which the muscle exerts its contractile force

Front 36

Maximum efficiency of normal heart

Back 36

20-25 percent (most energy converted to heat)

Front 37

Liters pumped per minute at rest and exercise

Back 37

4-6 L/min at rest (4-7 times this during exercise)

Front 38

Frank-Starling mechanism

Back 38

intrinsic ability for heart to adapt to increasing volumes of inflowing blood (stretch = greater contraction = greater quantity of blood pumped)

Front 39

Sympathetic stimulation of heart

Back 39

Can raise pulse from resting 70 to 180-200; also can double force of contration

Front 40

No sympathetic stimulation causes…

Back 40

decrease of cardiac pumping by 30% (there is generally always sympathetic stimulation)

Front 41

parasympathetic stimulation

Back 41

can stop heartbeat for few seconds, decreases contratile strength 20-30% (most fibers in atria)

Front 42

excess potassium

Back 42

heart become dilated and flaccid; heart rate slows; can vlock impulse from atria to ventricles

Front 43

excess calcium

Back 43

toward spastic contration(kept in narrow range in body - rarely seen)

Front 44

calcium deficiency

Back 44

cardiac flaccidity (kept in narrow range in body - rarely seen)