cardiac muscle

Question 1

what is the flow of blood in the heart called?

Answer 1

closed circuit

Question 2

superior + inferior vena cava carry ______ O2 blood to the _____ atrium

Answer 2

low; right

Question 3

blood flows from right atrium through the _____ valve to right ventricle

Answer 3

tricuspid (right AV)

Question 4

when the right ventricle contracts, where does blood go?

Answer 4

pulmonary trunk/arteries to lungs

Question 5

what separates the right ventricle from the lungs?

Answer 5

pulmonary semilunar valve

Question 6

where does oxygenated blood return to?

Answer 6

left atrium

Question 7

blood flows from left atrium through the ____ valve to left ventricle

Answer 7

bicuspid (mitral/left AV)

Question 8

when the left ventricle contracts, where does blood go?

Answer 8

ascending aorta to the rest of the body

Question 9

what separates the left ventricle from the aorta?

Answer 9

aortic semilunar valve

Question 10

what happens at the capillaries

Answer 10

O2 moves into tissues and CO2 moves out

Question 11

atria

Answer 11

upper/receiving chambers

Question 12

ventricles

Answer 12

lower, discharging chambers

Question 13

atrial syncytium

Answer 13

all atrial muscle fibers depolarize + contract together. act as a weak primer pump

Question 14

ventricular syncytium

Answer 14

all ventricular muscle fibers depolarize + contract together. main pumping force of blood

Question 15

ventricular systole

Answer 15

period of ventricular muscle contraction

Question 16

ventricular diastole

Answer 16

period of ventricular muscle relaxation

Question 17

atrial systole

Answer 17

period of atrial muscle contraction

Question 18

atrial diastole

Answer 18

period of atrial muscle relaxation

Question 19

excitatory + conductive fibers

Answer 19

generate + carry electrical signals through cardiac muscle

Question 20

what is the order of where an AP goes in the heart?

Answer 20

SA node > AV node > bundle of his (AV bundle) > bundle branches > purkinje fibers

Question 21

intercalated discs

Answer 21

cells membranes that separate individual cardiac muscle cells and are connected to each other

Question 22

desmosomes

Answer 22

physically joins adjacent myocardial cells together to prevent them from pulling apart

Question 23

gap junction

Answer 23

electrically joins myocardial cells togehter

Question 24

fascia adherens

Answer 24

anchoring site for actin filaments

Question 25

fibrous skeleton

Answer 25

connective tissue framework that separates/insulates the atrial syncytium from ventricular syncytium

Question 26

functional syncytium

Answer 26

all of the cells within a network contract simultaneously

Question 27

what is considered to be the pacemaker of the heart?

Answer 27

sinoatrial (SA) node

Question 28

why is the SA node considered to be the pacemaker of the heart?

Answer 28

because of its leaky sodium channels

Question 29

what causes nodal action potentials

Answer 29

leakage of sodium in until threshold is reached

Question 30

what happens at threshold?

Answer 30

voltage gated calcium channels open + calcium rushes IN

Question 31

sympathetic stimulation of cardiac muscle

Answer 31

norepinephrine activates beta-1 on SA node to increase heart rate

Question 32

parasympathetic stimulation of cardiac muscle

Answer 32

ACH binds to muscarinic cholinergic receptors on SA node to slow heart rate down

Question 33

Phase 4 of cardiac action potentials

Answer 33

Resting membrane potential

Question 34

Phase 0 of cardiac muscle action potential

Answer 34

Upstroke or depolarization

Question 35

Phase 1 cardiac muscle action potential

Answer 35

Initial repolarization

Question 36

Phase 2 of cardiac action potentials

Answer 36

Plateau

Question 37

Phase 3 of cardiac action potentials

Answer 37

Final repolarization

Question 38

Phase 4 characteristics

Answer 38

-85 to -90 mV. Na+/K+ pump and K+ leak channels

Question 39

Phase 0 characteristics

Answer 39

Depolarization. Na+ rushes in through voltage gated channels

Question 40

Phase 1 characteristics

Answer 40

Initial repolarization. K+ leaves the cell

Question 41

Phase 2 characteristics

Answer 41

Plateau. Open Ca2+ channels. Ca2+ in and K+ out

Question 42

Phase 3 characteristics

Answer 42

Final repolarization. All K+ channels open. K+ leaves the cell