Chp 18 class recording

Question 1

Differences between cardiac muscle action potential

Answer 1

steep/fast depolarization
has a plateau
and then we repolarize

Question 2

why does cardiac muscle plateau during action potential

Answer 2

we need to make sure is filling up all the ventricles

also because of calcium channels opening in the cardiac muscle fibers

Question 3

cardiac muscle at rest is what milivolt

Answer 3

-90

Question 4

what is the plateau for the cardiac muscles action potential

Answer 4

a maintained/sustained depolarization

Question 5

what causes the plateau

Answer 5

the calcium channels being slow to open

Question 6

does the heart gradually or quickly repolarize

Answer 6

gradually

Question 7

does the cardiac muscle have hyperpolarization

Answer 7

no, but we do have a period of rest

Question 8

depolarization happens because of

Answer 8

Na

Question 9

repolarization happens because of

Answer 9

K

Question 10

cardiac muscle action potential ion stages

Answer 10

Na
Ca
K

Question 11

Everytime you see ca you know what is happening in the heart

Answer 11

contraction and plaeua is happening

Question 12

even though we have no hyperpolarization we still need a protective mechanism so we aren’t sending messages to the sanode repeadtly. So when is that happening

Answer 12

in the middle of the plauteu is our absolute refractory period (when the heart is contracting)

Question 13

the slow depolarization is only happening at the SA node until we get to

Answer 13

threshold

Question 14

what kind of memebranes does the heart have and why

Answer 14

leaky, so I dont have to put as much effort into contraction

Question 15

why does the heart have leaky membranes

Answer 15

to increase it’s own control

Question 16

what can take over our pacemaker

Answer 16

sympathetic nervous system 
lack of calcium 
electrolyte balance 
caffeine, smoking, any kind of stimulant  
hypoxia (low oxygen) from anemia

Question 17

why does hypoxia speed up the heart overriding the sa node

Answer 17

because the heart has to work harder to give every tissue he same oxygen

Question 18

ectopic pacemakers are

Answer 18

outside factors overriding the pacemaker, stimulants, sanode damage hypoxia

Question 19

EKGs do what

Answer 19

measure the electrical activity at each junction

Question 20

electrical pathway of cardiac contractions

Answer 20

sa node
atrial muscle
av node
ventricular muscle

Question 21

contractions only happen where in the heart

Answer 21

the ventricular walls

Question 22

how long does it take the cardiac electrical muscle to send messages

Answer 22

.05 secs sa node to av node

.1 secs av node onwards (slows down)

Question 23

why does conduction slow in the heart

Answer 23

to allow the atria to fill with blood, send to ventricles

Question 24

three phases of the heart on EKG

Answer 24

p, QRS, T

Question 25

the most important phase in detecting actual contraction of the ventricles

Answer 25

QRS

Question 26

T wave on EKG is going where

Answer 26

back to rest

Question 27

p wave represents

Answer 27

sanode | atrial depolarization

Question 28

if I have an inverted p wave what can you assume?

Answer 28

they need a pace maker | and something is wrong with the sanode

Question 29

what does it mean if your QRS complex is drawn out?

Answer 29

contraction of the ventricles is slower

Question 30

what does the T wave represent

Answer 30

ventricular repolarization

Question 31

are invertted t waves common or uncommon... meaning what?

Answer 31

common, that we're not able to go back to rest and each contraction is not as strong

Question 32

what makes the heart sounds

Answer 32

when valves close

Question 33

the first heart sound we hear is made by

Answer 33

when our aortic and pulmonary valves close

Question 34

second heart sound is heard when what

Answer 34

av valves are closed

Question 35

what valves have to open to fill the ventricles with blood. And which valves are closed

Answer 35

av valves | exit valves

Question 36

blood drops down and ventricles

Answer 36

contract

Question 37

systole means

Answer 37

contraction of ventricles

Question 38

diastole means

Answer 38

relaxation of the ventricles

Question 39

isovolumetric contraction and relaxation is referring to

Answer 39

at the end of systole and diastole how much blood is left over

Question 40

the cardiac cycle always starts with

Answer 40

blood coming back to the heart

Question 41

ventricular contraction happens because

Answer 41

the av valves close

Question 42

the beginning of the ventricular systole

Answer 42

when the av valves close

Question 43

period of isovolumic contraction

Answer 43

systole (how much volume is in the ventricles at the end of systole)

Question 44

diastole happens

Answer 44

immediately after we contract

Question 45

period of isovolumic relaxation

Answer 45

diastole

Question 46

what valves have to be closed during diastole

Answer 46

semilunar

Question 47

at the end of diastole what is happening

Answer 47

the ventricles are completely filled and the av valves are open

Question 48

in the middle of diastole what is happening

Answer 48

the ventricles are filling

Question 49

initial filling of blood is called

Answer 49

isovolumetric relaxation | beginning of diastole

Question 50

then the cusps are completely open allowing blood to fill up

Answer 50

complete relaxtion | middle of diastole

Question 51

maxed out at that filling capacity of ventricles

Answer 51

end of diastole

Question 52

isometric contraction. just now sending the message to the purkinges fibers sending message to contract. av valves are closed and semilunar valves are open

Answer 52

initial phase of systole

Question 53

ventricular ejection of blood is what phase

Answer 53

middle of systole

Question 54

semilunar valves close means

Answer 54

end of systole

Question 55

what is stroke volume

Answer 55

how much blood is put out of the heart at each contraction

Question 56

how well this container is able to hold all of us before it explodes is called

Answer 56

preload

Question 57

contractility is exactly at the end of

Answer 57

systole

Question 58

how well the ventricular cardiac cells contracting is what

Answer 58

preload and contractility

Question 59

the pressure that the ventricles need to overcome because of volume in the atrium

Answer 59

afterload

Question 60

how does norepinephrine from the sympathetic nervous system how does it override the heart

Answer 60

opens calcium channels bypassing the sanode

Question 61

the heart increases the force contraction without increasing the length of the muscle is called

Answer 61

inotropic effect

Question 62

if the heart is overworked it starts to build more

Answer 62

myocradium

Question 63

an enlarged heart due to muscle growth

Answer 63

hypertrophy

Question 64

intrinsic effect of your pacemaker is

Answer 64

the sanode

Question 65

if your sanode is messed up who takes over

Answer 65

av node