cardio Chp 14

Question 1

what divides the left and right halves of the heart?

Answer 1

the septum

Question 2

what does the heart look like at day 25 of an embryo?

Answer 2

it is a single tube

Question 3

how has the heart developed at four weeks of development?

Answer 3

the atria and ventricles can be distinguished and the heart begins to twist do that the atria move on top of the ventricles

Question 4

which structures contain well oxygenated blood?

Answer 4

left atrium
left ventricle
pulmonary vein
aorta

Question 5

which structures contain blood with lower oxygen content?

Answer 5

right atrium
right ventricle
venae cavae
pulmonary trunk (artery)

Question 6

where does the right atrium receive blood from?

Answer 6

venae cavae

Question 7

where does the right atrium send blood to?

Answer 7

right ventricle

Question 8

where does the right ventricle get blood from?

Answer 8

right atrium

Question 9

where does the right ventricle send blood to?

Answer 9

the lungs

Question 10

where does the left atrium receive blood from?

Answer 10

pulmonary veins

Question 11

where does the left atrium send blood to?

Answer 11

left ventricle

Question 12

where does the left ventricle receive blood from?

Answer 12

the left atrium

Question 13

where does the left ventricle send blood to?

Answer 13

the body except for the lungs

Question 14

where does the venae cavae receive blood from?

Answer 14

systemic veins

Question 15

where does the venae cavae send blood to?

Answer 15

the right atrium

Question 16

where does the pulmonary trunk (artery) get its blood from?

Answer 16

right ventricle

Question 17

where does the pulmonary trunk send blood?

Answer 17

the lungs

Question 18

where does the pulmonary vein get it’s blood from?

Answer 18

veins of the lungs

Question 19

where does the pulmonary vein send its blood?

Answer 19

left atrium

Question 20

where does the aorta get its blood from?

Answer 20

the left ventricle

Question 21

where does the aorta send its blood to?

Answer 21

systemic

Question 22

which set of heart vales ensure one way flow?

Answer 22

atrioventricular valves

semilunar valves

Question 23

where are the atrioventricular valves?

Answer 23

between the atria and the ventricles

Question 24

which are artioventricular vales?

Answer 24

tricuspid valve on the right side 
bicuspid valve (mitral valve) on the left side

Question 25

where are the semilunar valves?

Answer 25

between ventricles and arteries

Question 26

which are semilunar valves?

Answer 26

aortic valve | pulmonary valve

Question 27

why do the AV valves stay closed during ventricular contraction?

Answer 27

to prevent blood flow backward into the atria

Question 28

what do the semilunar valves prevent?

Answer 28

blood that has entered back into the arteries from flowing back into the ventricles during ventricular contraction

Question 29

what causes the semilunar valves to close?

Answer 29

pressure

Question 30

pericardium

Answer 30

the fluid filled sac that encases the heart. It keeps out potential invaders and reduces friction due to movement of the heart

Question 31

what are the layers of the heart?

Answer 31

endocardium myocardium epicardium

Question 32

___ is the inner layer of epithelium

Answer 32

endocardium

Question 33

___is the middle layer of cardiac muscle

Answer 33

myocardium

Question 34

____ is the external membrane

Answer 34

epicardium

Question 35

contractile cells

Answer 35

striated fibers that are organized into sarcomeres

Question 36

autorhythmic cells are also called

Answer 36

pacemakers which work through gap junctions

Question 37

what do autorhythmic cells do?

Answer 37

signal for contraction

Question 38

autorhythmic cells are ____ compared to contractile cells

Answer 38

smaller and fewer

Question 39

autorhythmic cells do not have

Answer 39

organized sarcomeres

Question 40

what is the difference between cardiac muscle and skeletal muscle?

Answer 40

cardiac muscle is smaller and have a single nucleus per fiber branch and join other cells through intercalated disks the t-tubules are larger and branch sarcoplasmic reticulum is smaller mitochondria occupy 1/3 of cell volume

Question 41

what allows force to be transferred in intercalated disks?

Answer 41

desmosomes

Question 42

what provides the electrical connection between intercalated disks

Answer 42

gap junctions

Question 43

why is muscle relaxation so important?

Answer 43

that is when ventricular filling takes place. | the long refractory period also prevents tetanus

Question 44

in cardiac contraction, the force generated is proportional to:

Answer 44

the number of active crossbridges sarcomere length also affects the force of the contraction

Question 45

how do we control strength in cardiac contraction?

Answer 45

with calcium

Question 46

how do you produce a stronger contraction?

Answer 46

by increasing the number of crossbridges that form and power strokes that take place.

Question 47

what happens when you have too much extracellular K+?

Answer 47

you keep depolarizing cells which can lead to ectopic foci and arrhythmias as well as stop the heart

Question 48

what happens when you have extracellular Ca2+?

Answer 48

it prolongs the plateau phase and thus increases the time of contraction increases calcium which increases the strength of contraction force

Question 49

what does verapamil do?

Answer 49

it blocks ca influc to reduce contraction force

Question 50

what does digitalis do?

Answer 50

it increases intracellular ca thus increasing contraction strength

Question 51

which node sets the pace of the heartbeat at 70bpm?

Answer 51

sinoatrial node (SA)

Question 52

what does the atrioventricular node do?

Answer 52

it routes the direction of the electrical signals so that the heart contracts from apex to base

Question 53

what causes the first heart sound?

Answer 53

vibrations following closure for the AV valves | "lub"

Question 54

what causes the second heart sound?

Answer 54

vibrations created by closure of semilunar valve

Question 55

cardiac output:

Answer 55

the amount of blood pumped by each ventricle per minute

Question 56

how do you calculate cardiac output?

Answer 56

heart rate (beats per min) X stroke vol (vol ejected per beat)