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phys exam 3: ch 18 part 2

Total questions: 39

Worksheet time: 21mins

Name
Class
Date
1.

Coordinated heartbeats are a function of

a)

desmosomes

b)

gap junctions

c)

intrinsic cardiac conduction system

2.

Noncontractile cells are

a)

autorhythmic cells

b)

not this

3.

rapid, irregular contractions that cannot pump blood and eventually leads to brain death

a)

arrhythmias

b)

fibrillation

4.

intrinsic cardiac conduction system initiates and distributes impulses

a)

True

b)

False

5.

Have unstable resting membrane potentials due to opening of slow Na channels

a)

Myocardiocytes

b)

pacemaker cells (autorhythmic cells)

6.

myocardiocytes have fast gated Na channels

a)

True

b)

False

7.

At threshold in pacemaker cells, ___ channels open

a)

Na

b)

K

c)

Ca

8.

What causes the rising phase of the action potential in pacemaker cells?

a)

K efflux

b)

Ca influx

c)

Na influx

9.

Repolarization results from

a)

Ca channels closing

b)

Na channels opening

c)

K channels opening

d)

Na channels closing

10.

slow Na channels open

a)

pacemaker potential

b)

depolarization

c)

repolarization

11.

Ca channels open

a)

pacemaker potential

b)

depolarization

c)

repolarization

12.

Ca channels close and K channels open

a)

pacemaker potential

b)

depolarization

c)

repolarization

13.

Which one?

a)

pacemaker potential

b)

myocardiocyte potential

14.

Which one?

a)

pacemaker potential

b)

myocardiocyte potential

15.

put in order the sequence of excitation

a)

sinoatrial node

b)

atrioventricular node

c)

atrioventricular bundle

d)

right and left bundle branches

e)

subendocardial conducting network (Purkinje fibers)

1)
2)
3)
4)
5)
16.

"pacemaker of the heart"

a)

AV node

b)

SA node

17.

Where is SA node found?

a)

left atrial wall

b)

right atrial wall

18.

the SA. node depolarizes faster than the rest of the myocardium.

a)

True

b)

False

19.

SA node is responsible for heart rhythm

a)

true

b)

False

20.

Impulses from SA node spread across the atria to the

a)

skeletal muscle

b)

lungs

c)

AV node

d)

perkinjue fibers

21.

AV node ___ impulses for 0.1 seconds

a)

advances

b)

delays

22.

Which has fewer gap junctions?

a)

SA node

b)

AV node

23.

AV node allows atrial contraction prior to ventricular contraction

a)

T

b)

F

24.

the only electrical connection between atria and ventricles

a)

SA node

b)

bundle of His (AV bundle)

25.

subendocardial conduction network

a)

bundle of His

b)

perkinji fibers

26.

ventricular muscle has a plateau phase

a)

True

b)

False

27.

abnormal pacemaker

a)

ectopic focus

b)

extrasystole

c)

arrhythmia

28.

ectopic focus is a defective

a)

SA node

b)

AV node

29.

during ectopic focus, junctional rhythm is set by AV node and causes

a)

100 bpm

b)

80-90 bpm

c)

40-60bpm

30.

premature contraction that can be from caffeine or nicotine or when ectopic focus sets high rate

a)

extrasystole

b)

MI

c)

arrhythmia

31.

when few or no impoulses reach ventricles

a)

arrhythmia

b)

MI

c)

heart block

d)

ectopic focus

32.

defective AV node

a)

ectopic focus

b)

heart block

33.

defective SA node

a)

ectopic focus

b)

heart block

34.

how do you treat defective AV node?

a)

artificial pace maker

b)

not this

35.

sympathetic affect on heart will

a)

decrease contraction force

b)

increase HR

c)

decrease HR

d)

increase contraction force

36.

parasympathetic affect on the heart will

a)

decrease HR ONLY

b)

decrease HR and decrease force of contraction

37.

sympathetic and affects SA, AV nodes, heart muscle and coronary arteries

a)

cardioinhibitory center

b)

cardioacceleratory center

38.

parasypathetic and inhibits SA and AV nodes via vagus nerves

a)

cardioinhibitory center

b)

cardioacceleratory center

39.

study slides17-37

a)

yes

b)

no