1. Heart Overview and EC Coupling

Question 1

what is a mm of mercury pressure mean

Answer 1

reference system - how much pressure does it take to push up mercury one mm high in a tube?

Question 2

which part of heart pumps under very high pressure

Answer 2

left side

Question 3

if you increse pressure on right side what will happen to right ventricle

Answer 3

right ventricle will get bigger

Question 4

say blood flow of heart

Answer 4

right atrium through tricuspid valve to right ventricle to pulmonary valve to pulmonary artery to lungs to pulmonary veins to left atrium to mitral valve to left ventricle to aortic valve to aorta

Question 5

heart cells are connected by

Answer 5

intercalated disks and gap junctions

Question 6

in each part of the hart the AP is

Answer 6

different

Question 7

AP is intimately connected to

Answer 7

the function of the part of the heart it is located

Question 8

SA node is the

Answer 8

pacemaker of the heart

Question 9

describe resting potential in SA node

Answer 9

goes up - b/c it fires on its own

Question 10

draw out AP of SA node

Answer 10

pg 7

Question 11

draw out AP of atrial muscle

Answer 11

pg 7

Question 12

describe AP in ventricles muscle

Answer 12

sustained AP so the heart has enough time to pump out the blood

Question 13

what kind of gated channels are in ventricular muscle

Answer 13

voltage

Question 14

if positive charges leave the cell membrane wht happens

Answer 14

it is more negative

Question 15

if positive charges go into cell what happens

Answer 15

cell more positive

Question 16

phase 4 is

Answer 16

resting membrane potential

Question 17

what ion is primarily responsible for resting membrane potential

Answer 17

potassium

Question 18

phase 0 is called

Answer 18

depolarization pahse

Question 19

phase 0 what is happening

Answer 19

fast sodium channels open

Question 20

what causes fast sodium channels to open

Answer 20

sodium comes in and cause the membrane to reach the threshold and then the channels open and they rush in

Question 21

why does sodium rush inside cellw hen the channels open

Answer 21

positive ions outside b/c its negatively charged

down concentration & electrical gradient

Question 22

what does sodium do when it “closes”

Answer 22

inactivates

Question 23

what is happening in phase 1

Answer 23

fast sodium channels close (inactive)

fast potassium channels open

Question 24

what is phase 2

Answer 24

plateau phase

Question 25

what happens in phase 2

Answer 25

L type calcium channels open

fast potassium channels close

Question 26

why do calcium channels close

Answer 26

just time, they are open for certain amount of time then close

Question 27

what happens in phase 3

Answer 27

calcium channels close

SLOW potassium channels open

Question 28

what is the slow potassium channel called

Answer 28

delayed rectifier

Question 29

what does IKr stand for

Answer 29

potassium channel - delayed rectifier. it is the slow potassium channels

Question 30

what happens in phase 4

Answer 30

inward rectifier potassium channel Ik1

Question 31

what is Ik1

Answer 31

inward rectifier potassium channel

Question 32

what does AP look like in cell giving lidocain?

Answer 32

it will go up a lot slower, so phase 0 will be much slower (it blocks sodium channels)

Question 33

what does AP look like with potassium channel blockers

Answer 33

prlonged AP

Question 34

what is the absolute refractory period

Answer 34

nothing will cause aonther contraction/firing in that cell during the absolute refractory period

Question 35

what is the relative refractory period

Answer 35

a high enough stimulus will cause another AP

Question 36

why can’t there be another AP during absolute refractory period

Answer 36

the inactivation gates are still closed in sodium channels

Question 37

what does potassium blocker do to refractory period

Answer 37

makes refractory period longer

Question 38

if an area of the heart is ischemic, AP is now due to

Answer 38

calcium

look at pg 12

Question 39

say blood flow through the heart

Answer 39

pg 4