Cardiac Muscle

Question 1

cardiac muscle has smaller

Answer 1

sarcomere units ( like skeletal muscle)

Question 2

does cardiac muscle branch

Answer 2

yes–unlike skeletal

Question 3

junction between cardiac cells

Answer 3

intercalated discs (unlike skeletal)

Question 4

intercalated disks for

Answer 4

fast communication between cells–gap junctions–heart contraction all-or-nothing
Desmosomes–cell body for adhesion

Question 5

membrane surrounding cardiac muscle cells

Answer 5

sarcolema

Question 6

higher demand than skeletal thus

Answer 6

more T tubules, ATP, sarcoplasmic reticulum, slow Ca gates (allows for continuous contractal state)

Question 7

CCB

Answer 7

calcium channel blockers–decreases FORCE of contraction of heart

Question 8

arythmias happen during

Answer 8

end of absolute refractory period

Question 9

Ventricular Function measured by

Answer 9

Frank-Starling Curve– length-tension curve for heart (although not same as skeletal muscle shortening)

Question 10

which muscle type has more available Ca

Answer 10

cardiac–for sustained contractability

Question 11

heart failure means

Answer 11

lower stroke volume (amount of blood heart pushes out)

Question 12

volume of blood in heart after filling

Answer 12

end-diastolic volume

Question 13

beta-blocker

Answer 13

negative inotrope

Question 14

stroke volume at aorta

Answer 14

Afterload
X-axis: stroke volume
Y-axis: outflow resistance (afterload)
If resistance is high–output will be low

Question 15

enlargement of heart walls (cardiomyopathy)

Answer 15

hypertrophy–usually most noticeable at apex–will decrease volume able to enter ventricle

Question 16

hypertrophic heart complications

Answer 16

stiffening of wall

decreased volume

Question 17

myocardial labs

Answer 17

1. cardiac troponins: released into blood when heart damaged i.e MI
2. Serial Troponins taken–series over time

Question 18

Cell structure specialized for cell-cell adhesion btwn cardiac muscle cells

Answer 18

Desmosome–

Question 19

Agent that alters the force of energy of cardiac muscle contraction

Answer 19

Inotrope–negative inotropic agents weaken force of muscle contraction

Question 20

Increase velocity of contraction and SV

Answer 20

Positive inotropes

Question 21

Decrease velocity of contraction and SV

Answer 21

Negative inotropes

Question 22

Amount of resistance to ejection of blood from LV

Answer 22

Afterload

Question 23

Muscle with no troponin

Answer 23

Smooth muscle

Question 24

Less myosin

Answer 24

Smooth muscle– calmodulin

Question 25

<50% saturation ______ ________

Answer 25

Decreases contractility

Question 26

After load– resistance

Answer 26

Lower pressure >faster contraction

Heavier afterload>slower contraction

Question 27

Cardiac frank- starling curve relates

Answer 27

Stroke volume w/ ventricular filling–related to proper myosin/actin position at preload