power lab1

Question 1

ECG

Answer 1

electrocardiogram. Pattern of electrical activity recorded at the body surface

Question 2

Blood enters and exits where at what pressure?

Answer 2

enters the atrial chambers at a low pressure

exit the ventricles at a high pressure

Question 3

What provides the energy to force blood thru the circulatory system?

Answer 3

high arterial pressure

Question 4

What is picked up and what is released?

Answer 4

Oxygen picked up and carbon dioxide released

Question 5

Oxygenated blood is on what side of the heart?

Answer 5

left

Question 6

Are cardiac contractions dependent on a nerve supply?

Answer 6

no

Question 7

what modifies the basic cardiac rhythm?

Answer 7

Parasympathetic (vagus) and sympathetic = the central nervous system can affect the rhythm

Question 8

Sinus arrhythmia

Answer 8

where respiratory activity affects the heart rate

Question 9

what is the pacemaker of the heart?

Answer 9

sinoatrial node

Question 10

what does the SA node do?

Answer 10

produces rythmical contractions that push blood into the ventricles

Question 11

what is the only connection btw the atria and the ventricles?

Answer 11

av bundle

Question 12

pathway of impulse

Answer 12

slow thru the av node and fast thru the purkinje fibers

Question 13

the cardiac cycle involves what?

Answer 13

a sequential contraction of the atria and the ventricles

Question 14

what produces electrical currents?

Answer 14

combined electrical activity of the different myocardial cells

Question 15

the action potentails recorded from the av and ventricular fibers are different from what?

Answer 15

nerves and skeletal muscle

Question 16

what are the 3 phases of the cardiac action potential

Answer 16

1. rapid depolarization
2. plateau depolarization
3. repolarization

Question 17

what do the three areas on a wave indicate

Answer 17

Pwave: atrial depolarization
QRS Complex: ventricular depolarization, atrial repolarizaton
Twave: ventricular repolarization

Question 18

what functions as a pressure reservoir?

Answer 18

arterial system

Question 19

how does blood leave and enter the arterial system?

Answer 19

leaves thru the capillaries

enters intermittently from the heart

Question 20

what happens during systole

Answer 20

ventricles contract and the SL open

-arteries stretch and bp increases

Question 21

systolic pressure

Answer 21

peak pressure reached during the cardiac cycle

Question 22

diastole

Answer 22

period during the relaxation of the ventricles

Question 23

what drives the blood during diastole

Answer 23

elastic recoil of the major arteries

-arterial pressure decreases

Question 24

diastolic pressure

Answer 24

the period when the arterial blood pressure is at its lowest- immediately before the contracting ventricle pushes blood into the arteries again

Question 25

dicrotic nothch

Answer 25

caused by the closure of the AV valve - blood rebounding off of the atrioventricular wall

Question 26

how is the variation in arterial blood pressure during the cardiac cycle smoothed?

Answer 26

inherent elasticity of major arteries

Question 27

peak systolic wave appears when

Answer 27

after the QRS complex - time it takes to reach the peripheral arteries

Question 28

The 2 valves on each side of the heart do what?

Answer 28

convert the rhythmic contractions into unidirectional pumping

Question 29

what gives rise to audible vibrations

Answer 29

closure of the valves

Question 30

what prevents backflow from the ventricle to the atrium

Answer 30

AV valve

Question 31

what prevents back flow from the aorta and pulmonar artery into the respective ventricle?

Answer 31

SL valve

Question 32

what produces the "lub" sound?

Answer 32

closing of the AV valves

Question 33

what produces the "dub" sound?

Answer 33

closing of the SL valves

Question 34

malfunctions of the valves produce what?

Answer 34

audible murmurs

Question 35

what is occuring during ventricular diastole?

Answer 35

blood is returning to the heart

Question 36

in a resting state the atrial systole accounts for what percentage of atrial filling?

Answer 36

20%

Question 37

Isovolumic phase

Answer 37

until the pressure in the left ventricle exceeds that in the aorta the volume of the ventricles cannot change

Question 38

Blood moves because of what?

Answer 38

pressure gradient (high to low)

Question 39

the initiation of the cardiac conduction system is due to what?

Answer 39

autorhythmic cells

Question 40

do the autorhymic cells maintain a stable resting membrane potential?

Answer 40

no- they continually depolarize due to the gating kinetics of the ion channels they posses- pacemaker potentials

Question 41

what are the 5 main conduction segments?

Answer 41

1. SA node 2. AV node 3. AV bundle 4. Bundle branches 5. Purkinje fibers

Question 42

what has the most rapid conduction rate

Answer 42

SA node - 75bpm

Question 43

how is conduction spread throughout the atria

Answer 43

via gap junctions

Question 44

the AV node receives input from the SA node thru what?

Answer 44

internodal pathway

Question 45

where is signaling delayed while the atria finishes contracting

Answer 45

AV node

Question 46

the signal slows because of what?

Answer 46

fewer gap junctions and smaller diameter of conduction fibers

Question 47

what receives signal from the AV node

Answer 47

AV bundle

Question 48

what is the first segment linking atrial conduction to ventricular conduction?

Answer 48

AV bundle

Question 49

what receives signal from the AV bundle and sends it to the apex?

Answer 49

bundle branches

Question 50

what completes the conduction cycle?

Answer 50

purkinje fibers

Question 51

bulk of ventricular excitation occurs via what

Answer 51

purkinje fibers and gap junctional passage of signal between ventricular muscle cells

Question 52

where is the purkinje network more elaborate?

Answer 52

left side

Question 53

electrocardiogram

Answer 53

sum of all electrical potentials generated by the cells of the heart at any given time

Question 54

why is there a delay?

Answer 54

the atria finishes contracting

Question 55

what is the ELECTRICAL event of the cardiac cycle?

Answer 55

ventricular depolarization

Question 56

what is the MECHANICAL event of the cardiac cycle?

Answer 56

ventricles contract

Question 57

valves respond to changes in pressure due to what

Answer 57

muscular events

Question 58

depolarization leads to what?

Answer 58

contraction

Question 59

repolarization leads to what?

Answer 59

relaxation