Module 15 pt 2 Heart Physioology

Question 1

This system is a network of non-contractile cells that initiate and distribute impulses to coordinate the depolarization and contraction of the heart

Answer 1

Intrinsic cardiac conduction system

Question 2

These cells have a unstable resting potential due to the open slow Na+ channels, they continuously depolarize

Answer 2

Autorhythmic cells

Question 3

These autorhythmic cells are found in certain areas of the heart, including this node that is considered the pacemaker of the heart

Answer 3

Sinoatrial node

Question 4

How often does the SA node beat and what is the rhythm called?

Answer 4

90-95 times per minute, it is called the sinus rhythm

Question 5

What is unique about the SA node?

Answer 5

It depolarizes faster than any other part of the myocardium

Question 6

This node has fewer gap junctions and has a .1 second delay

Answer 6

Atrioventricular Node

Question 7

What is the reason for the .1 second pause of the AV node?

Answer 7

If there was no pause, the heart would be pumping blood against itself instead of through the valves

Question 8

This is the only electrical connection between the atria and the ventricles

Answer 8

AV bundle, or the bundle of HIS

Question 9

These are two pathways in the interverticular septum that carry the impulses towards the apex of the heart

Answer 9

Right and Left bundle branches

Question 10

This is the complete pathway into the apex and ventricular walls

Answer 10

Purkinje Fibers

Question 11

Irregular heart rhythms where there are uncoordinated atrial and ventricular contractions

Answer 11

Arrhythmias

Question 12

This is a homeostatic imbalances that is a rapid irregular contraction, useless for pumping blood

Answer 12

Fibrillation

Question 13

A defective node may result in an abnormal pacemaker takes over, like the AV node (40-60 bpm)

Answer 13

Ectopic Focus

Question 14

A defective SA node might result in a few or no impulses from the SA actually reach the ventricles

Answer 14

Partial or total heart block

Question 15

What is the heartbeat modified by?

Answer 15

Autonomic Nervous System

Question 16

Where are the cardiac systems located in the brain?

Answer 16

Medulla oblongata

Question 17

What does the Cardioinhibitory center inhibit and what through?

Answer 17

The SA and AV nodes through the vagus nerve

Question 18

This is a composite of all the action potentials generated by nodal and contractile cells at a given time

Answer 18

Electrocardiogram

Question 19

This is a wave in the ECG that shows the depolarization of the SA node

Answer 19

P wave

Question 20

This is a wave in the ECG that shows the ventricular depolarization

Answer 20

QRS complex

Question 21

This is a wave in the ECG that shows ventricular repolarization

Answer 21

T wave

Question 22

How many sounds are there associated with closing heart valves?

Answer 22

Two

Question 23

What does the first sound of the heart pertain to?

Answer 23

AV valve closes and begins systole

Question 24

The second sounds occurs when the heart does what?

Answer 24

The SL valves close at the beginning of ventricular disatole

Question 25

This is an abnormal heart sound that occurs most often indicative valve problems normally in the mitral valve

Answer 25

Heart Murmurs

Question 26

This includes all events associated with blood flow through the heart during on complete heart beat

Answer 26

Cardiac cycle

Question 27

What is the term used when the heart is contracting?

Answer 27

Systole

Question 28

What is the term used when the heart is relaxing?

Answer 28

Diastole

Question 29

In the phases of the Cardiac cycle, this is the first step when the AV valves are open and this happens mid-late diastole

Answer 29

Ventricular Filling

Question 30

After the AV valves open during ventricular filling, what happens that delivers the leftover 20% of blood remaining?

Answer 30

Atrial Systole

Question 31

This is the volume of the blood in each ventricle at the end of ventricular diastole

Answer 31

End-Diastolic volume

Question 32

This is the second phase of the Cardiac cycle when the atria and the ventricles begin to contract, rising pressure results in the closing of AV valves

Answer 32

Ventricular Systole

Question 33

This is the phase of the cardiac cycle when all of the valves are closed

Answer 33

Isovolumetric contraction

Question 34

In this phase, ventricular pressure exceeds pressure in large arteries forcing the SL valves open

Answer 34

Ejection phase

Question 35

This is a term that is the volume of blood remaining in each ventricle

Answer 35

End-systolic volume

Question 36

This is the final phase of the cardiac cycle that occurs in early diastole that is when ventricles relax

Answer 36

Isovolumetric relaxation

Question 37

This is the backflow of blood in the aorta and pulmonary trunk closes SL valve and causes this

Answer 37

Dicrotic Notch

Question 38

This is the volume of blood pumped by each ventricle in one minute

Answer 38

Cardiac Output

Question 39

What is the equation for cardiac output?

Answer 39

Heart rate X Stroke Volume

Question 40

What does the term cardiac reserve mean?

Answer 40

The difference between resting and maximal CO

Question 41

What are the three main factors that affect SV?

Answer 41

Preload Contractillity Afterload

Question 42

What does stroke volume equal?

Answer 42

End-diastolic volume minus End-systolic volume

Question 43

This is a regulation of stroke volume that is the degree os stretch of cardiac muscle cells before they contract

Answer 43

Preload | or Frank-Starling law of the heart

Question 44

This is a regulation of stroke volume when contractile strength at a given muscle length is independent of muscle stretch and EDV

Answer 44

Contractility

Question 45

This is an increase contractility which is an increase of calcium

Answer 45

Positive inotropic agents

Question 46

This is the decrease of contractility which is when calcium channels are blocked

Answer 46

Negative inotropic agents

Question 47

This is a regulation of stroke volume, the pressure that has to be overcome for ventricles to eject blood

Answer 47

Afterload

Question 48

What increases the regulation of heart rate

Answer 48

Positive chronotropic factors

Question 49

What decreases the increase of heart rate

Answer 49

Negative Chronotropic factors

Question 50

What is activated by emotional or physical stressors

Answer 50

Sympathetic nervous system

Question 51

What part of the nervous system opposes sympathetic effects

Answer 51

Parasympathetic system

Question 52

This is a sympathetic reflex initiated by increased venous return

Answer 52

Atrial reflex

Question 53

What hormone from the adrenal medulla enhances heart rate and contractility?

Answer 53

Epinephrine

Question 54

This is an abnormally fast heart rate that if persistent can lead to fibrillation

Answer 54

Tachycardia

Question 55

This is when the heart rate s slower than 60 bpm that can cause grossly inadequate blood circulation

Answer 55

Bradycardia

Question 56

This is a progressive condition where the CO is so low that blood circulation is inadequate to meet tissue needs

Answer 56

Congestive Heart Failure