Cardio Lec 5

Question 1

During re-polarization you have to put __ away

Answer 1

calcium

Question 2

How is calcium put away?

Answer 2

active transporter puts it back in SR

Question 3

Muscle cannot relax until __ & why

Answer 3

end of plateau phase bc you need to put calcium away

Question 4

Digitalis

Answer 4

used to treat severe heart failure

Question 5

What does digitalis do

Answer 5

inhibits Na/K pump -> Na accumulates in cell

Question 6

The more calcium

Answer 6

the more forceful the contraction bc you get more actin & myosin interactions

Question 7

What happens when Na accumulates in the cell

Answer 7

Na/K EXCHANGER will pump Na out in exchng for Ca in -> heart contracts more forcefully (pos. ionotropic agents)

Question 8

Positive ionotropic agent

Answer 8

drugs that cause a more forceful contraction

Question 9

Tetanization

Answer 9

when muscle stimulated so rapidly that theres no time for it to relax STAYS CONTRACTED -> muscle fatigues quickly bc using available enegy

Question 10

Is tetanization favorable for cardiac muscle?

Answer 10

no -> CO would be 0 bc heart would stay contracted & wouldnt be able to fill AND bc it would fatigue

Question 11

How does the heart not tetanize?

Answer 11

by having long absolute refractory periods heart wouldn’t respond to another stimulus bc wouldn’t be able to fire another action potential

Question 12

How does tetanization occur?

Answer 12

by firing repetitive action potentials

Question 13

T/F: Perkinje fibers have to spread impulses through ventricular myocytes very RAPIDLY, but if left to pace heart on their own fire action potentials infrequently -> lower hr

Answer 13

T

Question 14

Signal gets delayed at the __, because

Answer 14

AV node bc it allows ventricles time to fill

Question 15

EKG records

Answer 15

electrical activity of heart (ALL action potentials of ALL cells of heart)

Question 16

T/F: EKG measures valve tension

Answer 16

F

Question 17

P wave represents

Answer 17

atrial depolarization -> atrial contraction

Question 18

Is it possible to have another contraction come in prior to relaxation occurring?

Answer 18

no

Question 19

When is absolute refractory period over?

Answer 19

after heart has relaxed so you cant tetanize as a result

Question 20

QRS com

Answer 20

ventricular depolarization -> ventricular contraction & atrial repolarization

Question 21

T wave

Answer 21

ventricular repolarization -> relaxation

Question 22

What do the waves show?

Answer 22

electrical activity

Question 23

You have to ___ before you can contract, & ___ before you can relax

Answer 23

depolarize; repolarize

Question 24

SA node spreads the wave of ___ through the atria

Answer 24

depolarization (causes P wave)

Question 25

If P wave is missing, indicates

Answer 25

no SA node activity bc SA node sends wave of depolarization

Question 26

PVC's on their own are not problematic

Answer 26

T

Question 27

In ventricular fibrillation heart has no

Answer 27

coordinated depolarization & no ventricular output

Question 28

Heart block

Answer 28

missing qrs complexes & t-waves so AV node blocked in some instances

Question 29

When does the AV valve close

Answer 29

beginning of ventricular systole/contraction

Question 30

In an EKG when do you heart 1st heart sound

Answer 30

peak of R wave (where ventricular contraction begins)

Question 31

In an EKG when do you heart 2nd heart sound

Answer 31

when semilunar valves close (when ventricular repolarization/relaxation begins) shortly after T wave

Question 32

Bradycardia

Answer 32

hr < 60 bpm

Question 33

Is a hr < 60 bpm always abnormal?

Answer 33

no; norm in athletes or if in good shape

Question 34

Tachycardia

Answer 34

PERSISTENT hr > 100 bpm at rest

Question 35

Is tachycardia always abnormal?

Answer 35

no; if doing exercise its norm

Question 36

Tachycardia can result in an

Answer 36

ectopic foci

Question 37

If tachycardia originates in atria, called

Answer 37

supraventricular (SVT) MOST ARE BENIGN

Question 38

If tachycardia originates in ventricles, called

Answer 38

(V Tach) BAD ONES

Question 39

Flutter means

Answer 39

really fast beats but contraction is coordinated so blood being mobilized

Question 40

Fibrillation

Answer 40

no mobilization, no coordinated contraction, no blood mvmnt (heart quivers)

Question 41

V-fib

Answer 41

FATAL due to circus movements (reentry)

Question 42

A-fib

Answer 42

not immediately threatening bc ventricles receive most blood vol in absence of contraction -> predisposition to clots bc blood sits stagnant in walls of atria

Question 43

Atrial flutters turns quickly to

Answer 43

A-fib

Question 44

Defibrillation

Answer 44

can revert v-fib; depolarizes all cells at same time (resets) -> buys time

Question 45

Cardiac output refers to

Answer 45

vol of blood pumped per min by each ventricle

Question 46

Cardiac output =

Answer 46

SV x HR

Question 47

Stroke vol refers to

Answer 47

amount of blood ejected in one beat

Question 48

HR refers to

Answer 48

of beats per min

Question 49

Avg HR

Answer 49

70 bpm

Question 50

Avg SV

Answer 50

70 mls x beat

Question 51

Avg CO

Answer 51

5L/min

Question 52

If cardiac demands go up ->

Answer 52

hr incr -> contractile force incr -> SV incr -> CO incr

Question 53

Cardiac reserve

Answer 53

COmax - COrest

Question 54

How much cardiac reserve do people with severe heart disease have?

Answer 54

little to none

Question 55

What the heart kicks the into high gear

Answer 55

SNS