Lab 8

Question 1

Functional syncytium of muscle fibers, and the individual cells are electrically coupled

Answer 1

Cardiac Muscle

Question 2

Impulse in a cardiac muscle is

Answer 2

all or none

Question 3

the cardiac muscle contract more forcefully when stretched within limits

Answer 3

Starling’s law

Question 4

cardiac muscle is made up of bulk of

Answer 4

myocardium

Question 5

cells that contract without external stimulus

Answer 5

autorhythmic

Question 6

the rate at which a heart beat is determined by what part of the heart? located at the rear of the heart

Answer 6

SA node

Question 7

normal heart beat

Answer 7

70-75 times/minute

Question 8

factors that influence the cardiac muscle contraction

Answer 8

nervous input, chemical & metabolic change, temperature

Question 9

coordination of heart beat is due to the specialized conduction pathways located where?

Answer 9

in and between the atria and the ventricle

Question 10

one feature of the path

Answer 10

delay of the AV node

Question 11

allows the atria to complete their contraction before the ventricles begin to contract

Answer 11

delay of the AV node

Question 12

(pacemaker) due to changes in the membrane channel conductances of

Answer 12

K, Ca, Na

Question 13

ionic fluzes are modified by autonomic inputs, rate and force of contraction of heart can be

Answer 13

increase, decrease

Question 14

frog heart has ___ chambered

Answer 14

3 (2 atria and 1 ventricle)

Question 15

human heart has ____chambers

Answer 15

4 (2 A and 2 V)

Question 16

where deoxygenated blood arrives

Answer 16

RA

Question 17

where oxygenated blood arrives

Answer 17

LA

Question 18

after passing in the atrium it goes to the

Answer 18

Ventricles

Question 19

During ventricular systole the blood leaves through what?

Answer 19

truncus arteriosus

Question 20

this prevents the mixing of deoxy and oxygenated blood

Answer 20

truncus arteriosus

Question 21

heart is enclosed by

Answer 21

pericardium

Question 22

ion that play important tole in excitation contraction coupling sequence

Answer 22

Ca

Question 23

the excitation starts from __ to ___

Answer 23

atria to AV node

Question 24

where electrical impulses travel

Answer 24

bundle of His and purkinje fibers

Question 25

condition when the wave of excitation-contraction E-C can not proceed because of infarct or mechanical obstruction

Answer 25

heart block

Question 26

atria is dependent on ventricle

Answer 26

true

Question 27

cardiac influence extrinsic and intrinsic factors

Answer 27

neural hormonal. chemical, physical etc

Question 28

change in heart rate can be applied by adding para and sympa stimuli

Answer 28

chronotropic effect

Question 29

speed up the heart

Answer 29

epinephrine and norepinephrine

Question 30

slows down the heart

Answer 30

acetylcholine

Question 31

flow that keeps the pace of the heart..under the control via

Answer 31

tonic parasympathetic | vegal tone

Question 32

this effects can also be seen after administration of drug, including receptors, or channels or blockers

Answer 32

chronotropic effects

Question 33

use as a beta blocker, decreases heart rate

Answer 33

propanolol

Question 34

induces faster heart rate by blocking muscarinic type of acetylcholine receptors

Answer 34

atropine

Question 35

change in force, positive or negative, observed by altering the degree of stretch of the cardiac muscle fibers

Answer 35

inotropic effect

Question 36

stretching the heart can achieved by

Answer 36

filling the heart more with blood during diastole

Question 37

more Ca means

Answer 37

more availability of greater force

Question 38

effect when epinephrine and norepinephrine are applied

Answer 38

inotropic effect

Question 39

channel blockers used to decrease the force generated by the heart

Answer 39

Ca channel blockers

Question 40

increase the chart speed and make a record of several bears

Answer 40

contractile sequence

Question 41

recorded ventricular contractions under normal condition and effects of chemicals when applied

Answer 41

ventricular contraction

Question 42

effects on the heart rate

Answer 42

chronotropic

Question 43

effects on the force of contraction

Answer 43

inotropic

Question 44

length of the cardiac fiber can be changed by

Answer 44

adjusting the tension