L17: Cardiovascular System II

Question 1

different types of heart cells

Answer 1

express unique combination of ion channels and thus have different action potential shapes

Question 2

first depolarization

Answer 2

rapid depolarization due Na+ inflow when voltage-gated fast Na+ channels open

Question 3

then cells maintain depolarization

due

Answer 3

slow Ca2+ inflow when voltage-gated slow Ca2+ channels open and K+ inflow when some K+ channels open

Question 4

repolarization due to

Answer 4

closure of Ca2+ channels and K+ outflow when additional voltage-gated K+ channels open

Question 5

SA node cells are responsible for

Answer 5

autorhythmicity of the heart

Question 6

SA node cells do not have

Answer 6

steady resting potentials

Question 7

SA node cells are able to

Answer 7

spontaneously generate their own action potentials

Question 8

SA node cells have unique channels

Answer 8

open when the membrane potential is at negative values

Question 9

SA node unique channels are called

Answer 9

funny type channels

Question 10

funny type channels

Answer 10

non-selective cation channels and conduct an inward, depolarizing Na+ current

Question 11

ECG represents

Answer 11

the summed electrical activity of all cells recorded from the surface of the body

Question 12

ECG is used

Answer 12

to evaluate the electrical events within the heart because salt solutions are good conductors

Question 13

ECG gets

Answer 13

summed electrical activity generated by all cells of the heart

Question 14

ECG device measures

Answer 14

potential differences between selected electrodes

Question 15

each electrode pair constitutes

Answer 15

one positive and one negative electrode

Question 16

ECG has __ leads and is recorded using various combinations of the __ electrodes and another __ electrodes on the chest and trunk

Answer 16

12, 3 limb, 6

Question 17

lead 1

Answer 17

negative –attached to the right arm;

positive – attached to the left arm

Question 18

three major waves on a normal ECG

Answer 18

the P wave, QRS complex, and the T wave

Question 19

the first wave __ corresponds to ___

Answer 19

P wave, depolarization on the atria

Question 20

the next trio of waves ____ represents ____

Answer 20

QRS complex, the progressive wave of ventricular depolarization

Question 21

the final wave __ represents ____

Answer 21

T wave, repolarization of the ventricles

Question 22

4 major questions when interpreting ECG

Answer 22

• what is the heart rate?
• is the rhythm of the heartbeat regular?
• are all the waves present in recognizable form?
• is there one QRS complex for each P wave? If yes, is the P-R segment constant in length?

Question 23

heart rate is timed

Answer 23

from the beginning of one P-wave to the beginning of the next P-wave

Question 24

normal resting heart-rate

Answer 24

60-100 beats per minute (bpm)

Question 25

trained athletes typically have ___ heart rates

Answer 25

lower

Question 26

tachycardia

Answer 26

faster-than-normal heart rate

Question 27

bradycardia

Answer 27

slower-than-normal heart rate

Question 28

arrhythmia results from

Answer 28

a benign extra beat or atrial fibrillation

Question 29

ventricular tachycardia

Answer 29

rapid heart-beat that starts in the ventricles that can occur as a result of heart-attack

Question 30

if there are P waves without initiating a QRS complex

Answer 30

heart block, action potentials from the SA node can fail to be transmitted through the AV node to the ventricles

Question 31

systole

Answer 31

ventricular contraction phase involving blood ejection from the heart

Question 32

diastole

Answer 32

ventricular relaxation involving blood injection into the heart

Question 33

systole is subdivided into 2 periods

Answer 33

isovolumetric ventricular contraction and ventricular ejection

Question 34

isovolumetric ventricular contraction

Answer 34

ventricles contracting but all valves are closed, no blood ejected, ventricular volume is constant, raising ventricular blood pressure

Question 35

ventricular ejection

Answer 35

semilunar valves are open, blood is forced into aorta and pulmonary artery, the blood volume ejected = the stroke volume (SV)

Question 36

diastole periods

Answer 36

isovolumetric ventricular relaxation, ventricular filling

Question 37

isovolumetric ventricular relaxation

Answer 37

valves are closed, volume is not changing

Question 38

ventricular filling

Answer 38

the AV valves are open and blood flows in from the atria, atrial contraction occurs at the end of diastole, 80% of filling occurs before atrial contraction

Question 39

left ventricular pressure changes

Answer 39

in mid-diastole, ventricular pressure remains low until atrial contraction; in systole, a large increase in ventricular pressure; in early diastole, ventricular pressure falls to near zero (relaxation), and then slowly creeps back by passively filling with blood

Question 40

aortic pressure changes in diastole

Answer 40

no blood enters the aorta, semilunar valve is closed, blood leaves the aorta downstream, causing a slow decline in aortic pressure

Question 41

diastolic pressure

Answer 41

minimal aortic pressure at the end of the diastole and decline

Question 42

aortic pressure in systole

Answer 42

the semilunar valve opens and the aortic pressure rises quickly, blood flows more quickly into the aorta then it moves out

Question 43

maximal aortic pressure

Answer 43

systolic pressure

Question 44

aortic pressure at the end of systole

Answer 44

the semilunar valve closes, which causes a transient increase in aortic pressure called the dicrotic notch

Question 45

stroke volume

Answer 45

volume of blood ejected by the ventricle each beat

Question 46

end-diastolic volume (EDV)

Answer 46

volume of blood in ventricle reached just before the start of ejection (at the end of diastole)

Question 47

end systolic volume (ESV)

Answer 47

volume of blood in ventricle following ejection (at the end of systole)

Question 48

left ventricular volume relationship formula

Answer 48

Stroke volume = End Diastolic Volume - End Systolic Volume

Question 49

heart sounds result from

Answer 49

turbulent blood flow generated by valve closing

Question 50

first heart sound

Answer 50

AV valves close simulataneously

Question 51

second heart sound

Answer 51

semilunar valves close simultaneously

Question 52

abnormal heart sounds

Answer 52

heart murmurs

Question 53

most causes of heart murmurs in adults

Answer 53

valve problems

Question 54

stenotic valve

Answer 54

stiff, narrowed valve that does not open completely (aortic stenosis)

Question 55

incompetent valve

Answer 55

blood flows backward through the insufficient valve and collides with blood moving forward creating a "swishing" murmur (aortic regurgitation)