Exam 2- Chapter 17

Question 1

cardiac muscle cells

Answer 1

contain myoglobin (protein that carries oxygen)

Question 2

how does the heart contract

Answer 2

gap junction
cardiac muscle cells rapidly spread electrical activity via electrical synapse

Question 3

conduction system

Answer 3

1. SA nose
2. Intermodal pathways
3. AV node
4. AV bundle
5. Bundle branches
6. Purkinje fibers

Question 4

positive chronotropic agents

Answer 4

anything that increases HR

Question 5

negative chronotropic agents

Answer 5

anything that decreases HR

Question 6

how does the sympathetic NS increase CO (which effects HR)

Answer 6

-sympathetic NS intervates the heart via sympathetic nerves
-sympathetic nerves release norepinephrine which increase CO with positive chronotropic agents

Question 7

how does the parasympathetic NS decrease CO (which effects HR)

Answer 7

-intervates the heart by left + right vagus (X) nerve
- Vagus (X) nerve releases acetylcholine which decreases CO generation

Question 8

where does the heart get energy for contractions

Answer 8

myoglobin in cardiac muscle cells & mitochondria in cytoplasm of cardiac muscle

Question 9

P wave

Answer 9

atrial depolarization (systole)

Question 10

QRS complex

Answer 10

ventricular depolarization (systole)
(masking atrial repolarization)

Question 11

T wave

Answer 11

ventricular repolarization (diastole)

Question 12

R-R interval

Answer 12

entire duration of heartbeat
used to take heart rate

Question 13

P-R interval

Answer 13

duration of atrial depolarization
av node delay

Question 14

Q-T interval

Answer 14

duration of ventricular action potential

Question 15

S-T segment

Answer 15

ventricular pleatau phase

Question 16

1. ventricular filling phase

Answer 16

-blood drains atria –> ventricles
-AV valves open in high pressure in atria & close in high pressure in ventricles
-after atria systole, 120 ml of blood is in ventricles (end diastolic volume)

Question 17

2. isovolumetric contraction phase

Answer 17

-ventricle systole begins
-AV valves & systole valves close while pressure builds in ventricles

Question 18

3. ventricular ejection

Answer 18

-pressure in ventricles open semilunar valve and blood ejects into pulmonary artery or aorta
-70 ml of blood from each ventricle
- 50 ml remain after ventricular systole (end systolic volume)

Question 19

4. isovolumetric relaxation phase

Answer 19

-semilunar valves close bc pressure builds in ventricles

Question 20

“lub” or S1

Answer 20

AV valves close

Question 21

“dub” or S2

Answer 21

semilunar valves close

Question 22

cardiac output

Answer 22

amount of blood the heart pumped in 1 min

Question 23

stroke volume

Answer 23

amount of blood in 1 heartbeat

Question 24

average heart rate

Answer 24

average of 60-80 bpm

Question 25

__ + ___ = HR

Answer 25

SV + CO = HR

Question 26

positive chronotropic agents that influence HR

Answer 26

-norepinephrine
-epinephrine
-glucagon
-aldosterone
-antidiuretic

Question 27

negative chrontropic agents that influence HR

Answer 27

-acetylcholine
-ANP

Question 28

factors that contribute to HR

Answer 28

-age
-physical fitness
-exercise

Question 29

coronary artery disease

Answer 29

build up of fatty material (plaques) in coronary artery
-decreases blood flow (oxygen) to myocardium –>myocardial ischemia

Question 30

symptoms of coronary artery disease

Answer 30

chest pain –>angia pectoris

Question 31

most dangerous consequence of coronary artery disease

Answer 31

heart attack –> myocardial infarction