Introduction And Electrical Activity Of The Heart

Question 1

How is the heart set up as?

Answer 1

2 pump system

Question 2

What direction does blood flow

Answer 2

Unidirectional

Question 3

Right side of hte heart

Answer 3

Pulmonary system

Question 4

Left side of the heart

Answer 4

Systemic system

Question 5

Where is the biscuit (mitral) valve?

Answer 5

Between left atrium and left ventricle

Question 6

Where is the tricuspid valve

Answer 6

Between the right atrium and the right ventricle

Question 7

Period of contraction, force generation and blood expulsion

Answer 7

Systole

Question 8

Period of relaxation, filling with blood, readying for next systole

Answer 8

Diastole

Question 9

Blood is carried via ________ to capillary beds in organs

Answer 9

Arterial system

Question 10

Blood returns to the heart via ________ system

Answer 10

Venous

Question 11

Blood volume

Answer 11

Always constant. Increase in one area causes a loss elsewhere.

Blood shifts from GI tract to the skeletal muscles when you need to run from something

Question 12

Left A fib wold most greatly affect filling of which other heart chambers?

Answer 12

Left ventricle

Question 13

nodes

Answer 13

Highly modified myocytes
No contraction, only APs
Connected to myocytes via gap junctions

Question 14

How are nodes connected to myocytes

Answer 14

Via gap junctions

Question 15

What are the nodes responsible for?

Answer 15

Rhythmic excitation and coordinated contraction of heart muscle

Question 16

How are nodes controlled?

Answer 16

Auto rhythmic but modulated by ANS

Question 17

What leads to arrhythmia and altered pump functions

Answer 17

Dysregulation of nodes

Question 18

What is the first node to depolarize

Answer 18

Sinus node (sinoatrial node)

Question 19

What is the pacemaker of the heart

Answer 19

Sinoatrial node

Question 20

What does the SA node cause

Answer 20

Atrial contraction

Question 21

What allows the atria to fully contract before ventricles do?

Answer 21

The fact that the AV node has a reduced conduction velocity, fewer gap junctions

Question 22

Which has fewer gap junctions, SA or AV node

Answer 22

AV node

Question 23

Which has slower AP, SA node or AV node?

Answer 23

AV node

Question 24

Where does the AV node carry AP?

Answer 24

From atria to ventricles

Question 25

Where is the SA node (pacemaker)?

Answer 25

Right atrium

Question 26

Steps of conduction

Answer 26

SA node- Av node - bundle of His - perkinje system - ventricular monocytes

Question 27

What part of node system is super fast (other than SA node)

Answer 27

Purkinje system - large diameter cells - fast AP - speeds conduction to ventricular myocytes

Question 28

What allows for maximal blood ejection

Answer 28

Coordination of depolarization

Question 29

Flow of depolarization

Answer 29

SA nodes-atria depolarizes-septum and inner layer of ventricular muscle depolarizes-ventricles depolarize

Question 30

All of the heart is _____

Answer 30

Auto rhythmic | All have different depolarization rates

Question 31

Why is SA node pacemaker?

Answer 31

Because it is the fastest

Question 32

Why is the SA node the fastest

Answer 32

It fires while the others are still slowly depolarizing | -overdriving suppression

Question 33

Firing rate of SA node

Answer 33

70-80

Question 34

Ectopic pacemaker can override SA node if

Answer 34

SA node slows Ectopic is faster Pathology introduces a conduction block

Question 35

What is the heart innervated by

Answer 35

Both the sympathetic and parasympathetic NS

Question 36

What primarily controls the SA/AV nodes?

Answer 36

Parasympathetic

Question 37

Heart rate is modulated by

Answer 37

- altering SA node firing rate | - altering conduction through the AV node

Question 38

What Node do we care about the speed?

Answer 38

SA node only

Question 39

Anything that effects the heart rate

Answer 39

Chronotrope

Question 40

What causes a positive chronotrope?

Answer 40

Sympathetic - increase HR - B1 receptors - increase funny channels - increase Ca current

Question 41

What causes negative chronotrope

Answer 41

Parasympathetic - reduce HR - M2 receptors - decreases funny current - decreases Ca current - increases K current

Question 42

Something that affects conduction velocity

Answer 42

Dromotrope

Question 43

What causes positive dromotrope

Answer 43

Sympathetic - increases conduction velocity - B1 receptors - increase Ca current during upstroke - shortens ERP

Question 44

What causes negative dromotrope?

Answer 44

Parasympathetic - slows conduction velocity - lengthen AV nodal delay - M2 receptors - decrease Ca current - increase K current - lengthens ERP

Question 45

What node is involved with chronotrope

Answer 45

SA

Question 46

What node is involved in dromotropy

Answer 46

AV

Question 47

Measures the electrical activity of the heart over time

Answer 47

EKG X axis big square equals 200 milliseconds Taxis big square is .5mV

Question 48

Measured changes in voltages on EKG

Answer 48

Waves

Question 49

Time periods that include the wave

Answer 49

Intervals

Question 50

Time periods that do not include the wave

Answer 50

Segments

Question 51

What starts the P wave

Answer 51

SA node Atria is small, P wave is small

Question 52

Atrial depolarization on EKG

Answer 52

P wave

Question 53

Ventricular depolarization on ekg

Answer 53

QRS complex AV node

Question 54

Ventricular repolarization

Answer 54

T wave

Question 55

Purkinje repolarization in EKG

Answer 55

U wave Usually not seen. May indicated hypokalemia and hypercalcemia

Question 56

Time from initiation of atrial depolarization to initiation of ventricular depolarization

Answer 56

PR interval .12-.2 seconds

Question 57

Time from end of atrial depolarization to initiation of ventricular

Answer 57

PR segment

Question 58

Total time to depolarize ventricles

Answer 58

QRS interval

Question 59

Time from first ventricular depolarization to last repolarization

Answer 59

QT interval How long its refractory is

Question 60

Time from last depolarization to initiation of repolarization

Answer 60

ST segment Can be elevated during myocardial infarction (MI) - STEMI

Question 61

What effect would increasing parasympathetic tone have on the ECG?

Answer 61

Increase the PR interval

Question 62

What effect would a sodium channel (Na) blocker have on the ECG?

Answer 62

Increase the QT interval