chapter 19: cardiovascular physiology

Question 1

cardiac cycle

Answer 1

one heartbeat

-includes atrial contraction, ventricular contraction, a short pause during which the entire heart is relaxed

Question 2

systole

Answer 2

contraction of atria or ventricles

Question 3

diastole

Answer 3

the time when the atria or ventricles are relaxed

Question 4

what are the mechanical events of the heart?

Answer 4

systole and diastole

Question 5

mechanical events of the heart are preceded and caused by _____.

Answer 5

electrical events

Question 6

true or false: the hearts electrical events are NOT brought about by nerve impulses.

Answer 6

true

Question 7

1 % of cardiac muscle cells are ______, while the remaining 99% are _____.

Answer 7

autorhythmic cell while the remaining 99% are contractile cells

Question 8

autorhythmic cells

Answer 8

• do not contract
• initiate and conduct action potentials that spread throught the heart causing depolarization and repolarization of contractile cells

Question 9

depolarization leads to the contraction of ______ cells.

Answer 9

contractile cells

Question 10

repolarization leads to the ______ or contractile cells.

Answer 10

relaxation

Question 11

atrial relaxation is a _____ event.

Answer 11

mechanical event

Question 12

ventricular depolarization is an ______ event.

Answer 12

electrical event

Question 13

true or false: the heartbeat requires input from nerves

Answer 13

FALSE

Question 14

_____ cells initiate and conduct action potentials that cause the electrical events of the heart.

Answer 14

autorhythmic cells

Question 15

what three criteria must be met for the heart to efficiently pump blood through the vessels of the cardiovascular system?

Answer 15

1. excitation must be coordinated, so that the cells of each heart chamber contract as a unit
2. coordination between the paired atria and the paired ventricles so that both members of a pair contract at the same time
3. atrial excitation and resulting contraction must be completed before the onset of ventricular contraction

Question 16

explain the disadvantage in regards to blood flow if the cells of a ventricle do not contract as a unit

Answer 16

blood would not be pumped from a ventricle

Question 17

electrocardiogram ECG or EKG

Answer 17

recording of the electrical events of the heart

Question 18

the blips of the ECG in order

Answer 18

p q r s t

Question 19

p wave

Answer 19

caused by the spread of depolarization

Question 20

QRS complex

Answer 20

caused by the spread of depolarization through the ventricles

Question 21

t wave

Answer 21

caused by the spread of repolarization through ventricles

Question 22

atrial repolarization does not show on a normal ECG because:

Answer 22

it occurs at the same time as ventricular depolarization

Question 23

true or false: electrical events cause mechanical events

Answer 23

true

Question 24

why are the durations of mechanical and electrical events NOT the same?

Answer 24

because muscle fibers continue to contract until the cells are repolarized

Question 25

electrical and mechanical event of the p wave

Answer 25

electrical event: atrial depolarization causes mechanical event: atrial systole (contraction)

Question 26

electrical and mechanical event of the QRS complex

Answer 26

electrical: ventricular depolarization causes mechanical: ventricular systole

Question 27

electrical and mechanical event of the t wave

Answer 27

electrical : ventricular repolarization causes mechanical: ventricular diastole (relaxation)

Question 28

heart block

Answer 28

- change in the hearts electrical events | - ventricles often miss a beat

Question 29

PQ interval

Answer 29

time from the beginning of the p wave to the beginning of th QRS complex -beginning of atrial depolarization to the beginning of ventricular depolarization

Question 30

an increased pq interval indicates :

Answer 30

a delay in action potential traveling through the conduction system of the ventricles

Question 31

QRS interval

Answer 31

measure of how long it takes the ventricles to depolarize - usually less than .10 sec. - an enlarged ventricle can cause an increase QRS interval

Question 32

QT interval

Answer 32

contraction of the ventricle last almost from the beginning of the Q wave to the end of the T wave. - .35 sec - an enlarged ventricle can result in an increased QT interval

Question 33

an increased QT interval is a change in the _______.

Answer 33

duration of the hearts electrical events

Question 34

heart block is a change in the :

Answer 34

sequence of the hearts electrical events | because ventricles often miss a beat

Question 35

lead

Answer 35

each combination of two electrodes | only two electrodes are working at one time

Question 36

lead 1

Answer 36

records the difference in electrical potential between the electrodes on the right and left arms

Question 37

lead 2

Answer 37

records the difference in electrical potential between the electrodes on the right arm and left leg

Question 38

lead 3

Answer 38

records the difference in electrical potential between the electrodes on the left are and left leg

Question 39

the electrode on the right leg is the ______

Answer 39

ground electrode

Question 40

mean electrical axis QRS axis

Answer 40

the electrical line from the apex to the base

Question 41

any change in the mean electrical axis indicates a change in the ;

Answer 41

direction of electrical events of the heart

Question 42

the electrode on the right arm is always _____

Answer 42

negative

Question 43

the electrode on the left leg is always _____

Answer 43

positive

Question 44

one factor that influences the amplitude of an event is the _______ of an event

Answer 44

direction

Question 45

a recorded electrical event is largest in the lead that _______ the direction of that event

Answer 45

most closely parallels

Question 46

the mean electrical axis is almost parallel to lead ___?

Answer 46

lead 2

Question 47

any change in the mean electrical axis indicates a change in the ______ of electrical events in the heart.

Answer 47

direction of electrical events in the heart

Question 48

three examples of how mean electrical axis can change?

Answer 48

- pregnancy - if one ventricle is enlarged relative to the other - if areas of the heart muscle are damaged due to a heart attack

Question 49

during ventricular relaxation pressure increases or decreases?

Answer 49

decreases

Question 50

sound one occurs when

Answer 50

closure of the atrioventricular valves

Question 51

sound two occurs when

Answer 51

closure of the semilunar valves

Question 52

an abnormal heart sound is called a _____

Answer 52

heart murmur

Question 53

auscultation means

Answer 53

listening to body sounds

Question 54

systemic arteriol blood pressure

Answer 54

- most commonly measured | - provides most valuable info about condition of cardiovascular system and overall health

Question 55

the pressure in your arteries is pulsatile. what does pulsatile mean?

Answer 55

it rises and falls with each contraction and relaxation of the ventricles

Question 56

systolic pressure

Answer 56

highest arterial pressure attained during one cardiac cycle

Question 57

diastolic pressure

Answer 57

lowest arterial pressure attained during one cardiac cycle

Question 58

mean arteriol pressure

Answer 58

average pressure experience by arteries -homeostatically regulated by your body (1/3 x pulse pressure) + diastolic pressure

Question 59

pulse pressure=

Answer 59

systole - diastole

Question 60

pulse rate

Answer 60

of heart beats in one minute

Question 61

kortoff sounds do not occur when :

Answer 61

blood does not flow through the artery or when the blood flow is smooth -does not occur when there is no turbulece

Question 62

kortoff sound would be heard when blood ___.

Answer 62

spurts through the artery

Question 63

cardiac output =

Answer 63

heart rate X stroke volume

Question 64

resting pulse is taken. upon standing cardiac output basically remains constant, but stroke volume ______ due to the pull of gravity and heart rate _______ to keep cardiac output the same.

Answer 64

decreases due to the pull of gravity and increases to keep cardiac output the same

Question 65

define heart murmur

Answer 65

and abnormal heart sound

Question 66

different electrical views of the heart can be obtained using the three standard _____

Answer 66

limb leads

Question 67

give two durations or intervals that are prolonged due to an enlarged heart

Answer 67

QT interval, QRS

Question 68

_______ precedes and causes the ventricles to contract

Answer 68

depolarization precedes and causes the ventricles to contract