Chapter 18 - Part 2

Question 1

Characteristics of cardiac muscle

Answer 1

1) intercalated discs (unique)
2) branches
3) striation
4) uninucleate

Question 2

What junctions do intercalated discs have?

Answer 2

gap junctions and desmosomes

Question 3

Gap Junctions

Answer 3

allow ions to pass from cell to cell; makes heart functional syncytium

Question 4

Thick filament

Answer 4

Myosin

Question 5

Thin filament

Answer 5

actin

Question 6

What percentage of heart cells do pace maker cells make up?

Answer 6

1%

Question 7

What percentage of heart cells do cardiac muscle cells make?

Answer 7

99%

Question 8

Order of pacemaker cells

Answer 8

SA node, AV node, AV bundle (His bundle), Bundle branches, Purkinje fibers

Question 9

Automaticity

Answer 9

do not need nervous system stimulation; can depolarize entire heart

Question 10

Pace maker cells

Answer 10

modified cardiomyocytes

Question 11

SA node rate

Answer 11

fast and high

Question 12

P wave

Answer 12

atrial depolarization (excitation)

Question 13

QRS Complex

Answer 13

ventricular depolarization and atrial repolarization

Question 14

True or False: QRS stands for all of ventricular depolarization

Answer 14

False

Question 15

T Wave

Answer 15

ventricular repolarization

Question 16

Location of P-R interval

Answer 16

beginning of P wave to beginning of QRS

Question 17

What does the P-R interval represent?

Answer 17

represents beginning of atrial excitation to beginning of ventricular excitation

Question 18

Location of S-T segment

Answer 18

end of QRS to beginning of T wave

Question 19

What does the S-T segment represent?

Answer 19

entire ventricular myocardium depolarization

Question 20

Location of Q-T interval

Answer 20

beginning of QRS complex to end of T wave

Question 21

What does the Q-T interval represent?

Answer 21

beginning of ventricular depolarization through ventricular repolarization

Question 22

60/RR

Answer 22

heartrate

Question 23

True or false: ECG stands for physical heartbeat

Answer 23

False; just the electrical signal for heart beat

Question 24

what is the “lub” sound caused by?

Answer 24

closure of mitral and tricuspid valves

Question 25

what is the “dub” sound caused by?

Answer 25

closure of aortic and pulmonary valves

Question 26

stroke volume (sv)

Answer 26

volume of blood pumped out by one ventricle with each beat (70ml/beat)

Question 27

cardiac output (co)

Answer 27

volume of blood pumped by each ventricle in one minute

Question 28

HR(beats/min) x SV (ml/beat)

Answer 28

cardiac output (ml/min)

Question 29

regulation of SV and CO

Answer 29

autonomic nervous system via medulla oblongata

Question 30

what does the sympathetic nervous system do to SV and CO?

Answer 30

raise rate and force

Question 31

what does the parasympathetic nervous system do to SV and CO?

Answer 31

lowers rate and force

Question 32

What triggers heart beats?

Answer 32

pacemaker cells; calcium factors in