ch 19 practice exam pt 1

Question 1

choose correct statement(s) associated with the metabolism of cardiac muscle

Answer 1

cardiac muscle depends almost exclusively on anaerobic respiration

Question 2

choose correct statement(s) that accurately explains impulse conduction to the myocardium

Answer 2

• firing of the SA node excites atrial cardiomyocytes and stimulates the 2 atria to contract almost simultaneously
• in the AV node the signal slows down to about 0.05 m/sec because the cardiomyocytes have fewer gap junctions over which the signal can be transmitted
• the delay at the AV node is essential because it gives the atria time to fill with blood before they begin to contract

Question 3

which of the following are found on the surface of the heart

Answer 3

• coronary sulcus
• marginal sulcus

Question 4

the pulmonary circuit is supplied by both right and left sides of the heart

Answer 4

false

Question 5

systemic circuit contains oxygen-rich blood only

Answer 5

false

Question 6

which carry oxygen-poor blood

Answer 6

venae cava and pulmonary arteries

Question 7

which belongs to the pulmonary circuit

Answer 7

pulmonary arteries and pulmonary veins

Question 8

the heart is enfolded within a space called

Answer 8

pericardial cavity

Question 9

the apex of the heart is found _____ of the midline of the body

Answer 9

to the left

Question 10

which is the most superficial layer enclosing the heart

Answer 10

fibrous pericardium

Question 11

pericardial fluid is found between the _____ and the _____

Answer 11

parietal layer of the serous pericardium; visceral layer of the serous pericardium

Question 12

the fibrous skeleton of the heart serves as electrical insulation between the atria and the ventricles

Answer 12

true

Question 13

the ___ performs the work of the heart

Answer 13

myocardium

Question 14

the _____ are superior chambers of the heart and the ______ are the inferior chambers of the heart

Answer 14

atria; ventricles

Question 15

the ventricles are the thicker more powerful chambers of the heart, they pump blood to the lungs and body

Answer 15

true

Question 16

the shallow depression seen on the external surface of the heart between the left and right ventricles is called the

Answer 16

interventricular sulcus

Question 17

the area where the major vessels lead to and from the heart’s chambers is called the _____ of the heart. the pointy, inferior portion is called the _____

Answer 17

base; apex

Question 18

the right atrioventricular valve regulates the opening between the ________ and the ________

Answer 18

right atrium; right ventricle

Question 19

oxygen-poor blood passes through the

Answer 19

right AV and pulmonary valve

Question 20

the ______ valve regulated the flow of blood between the right ventricle and the vessels leading to the lungs

Answer 20

pulmonary

Question 21

the chordae tendineae of the AV valves are anchored to the _____ of the ventricles

Answer 21

papillary muscles

Question 22

the ______ carry blood toward the lungs

Answer 22

pulmonary trunk and arteries

Question 23

after entering the right atrium the furthest a RBC can travel is the ______

Answer 23

superior vena cava

Question 24

opening and closing of the heart valves is caused by

Answer 24

pressure gradients

Question 25

which of the following blood vessels receives blood directly from the right ventricles

Answer 25

pulmonary trunk

Question 26

which of the following directly stems from the ascending aorta before it branches into the circumflex branch and anterior interventricular branch

Answer 26

left coronary artery

Question 27

an obstruction in which of the following will cause the most severe myocardial infarction (MI)

Answer 27

left coronary artery (LCA)

Question 28

blood in the heart chambers provides most of the myocardium’s oxygen and nutrient needs

Answer 28

false

Question 29

cardiac muscle can only use glucose as a source of organic fuel

Answer 29

false

Question 30

which is a feature shared by cardiac muscle and skeletal muscle

Answer 30

muscle fiber striations

Question 31

which is NOT a feature of cardiac muscle

Answer 31

they have about the same endurance as skeletal muscle fibers

Question 32

desmosomes form channels that allow each cardiomyocyte to electrically stimulate its neighbors

Answer 32

false

Question 33

electrical signals pass between cardiomyocytes through the

Answer 33

gap junctions

Question 34

the _____ is the pacemaker that initiates each heart beat

Answer 34

sinoatrial (SA) node

Question 35

which is NOT part of the cardiac conduction system

Answer 35

tendinous cords

Question 36

which is the correct path of an electrical excitation from the pacemaker to a cardiomyocyte in the left ventricle (LV)

Answer 36

• sinuatrial (SA) node
• atrioventricular (AV) node
• subendothelial branches
• atrioventricular (AV) bundle
• cardiomyocyte in LV

Question 37

the pacemaker potential is a result of

Answer 37

Na+ inflow

Question 37

if the sinoatrial (SA) node is damaged the heart will likely beat at ____ bpm

Answer 37

40 to 50

Question 38

if the SA node is damaged nodal rhythm is sufficient to sustain life

Answer 38

true

Question 38

cells of the sinuatrial node ____ during the pacemaker potential

Answer 38

depolarize slow

Question 39

papillary muscle prevent the AV valves from prolapsing (bulging) excessively into the atria when the ventricles contract

Answer 39

true

Question 40

parasympathetic stimulation reduces heart rate

Answer 40

true

Question 41

the cardiac plexus and cardiac nerves dominate the innervation of the heart and contain both parasympathetic and sympathetic fibers

Answer 41

true