Intrinsic Conduction System/anatomy Of The Heart

Front 1

The contraction of the ventricles is referred to as _______.

Back 1

systole

Front 2

The period of ventricular relaxation is called the _____.

Back 2

diastole.

Front 3

The first heart sound is a result of closure of the ___ valves.

Back 3

AV

Front 4

The second heart sound is caused by closure of the ____ valves.

Back 4

SL

Front 5

The heart chambers that have just been filled when you hear the first heart sound are the the _____.

Back 5

ventricles.

Front 6

The pacemaker of the intrinsic conduction system is the ______.

Back 6

SA node

Front 7

The point in the intrinsic conduction system where the impulse is temporarily delayed. The atria contracts.

Back 7

AV node

Front 8

This node initiates depolarization.

Back 8

SA node

Front 9

This links the SA to the AV node.

Back 9

internodal pathway

Front 10

This is the link between atria and ventricles.

Back 10

AV bundle or bundle of his.

Front 11

This conveys impulse down the septum.

Back 11

bundle branchees.

Front 12

This conveys impulse throughout the ventricular walls.

Back 12

Purkinje fibers

Front 13

AV valve with 2 flaps.

Back 13

mitral

Front 14

AV valve with 3 flaps.

Back 14

tricuspid

Front 15

_____ and ____ prevent backflow into the ventricles when the heart is relaxed.

Back 15

Pulmonary valve and aortic valve

Front 16

____ and ____ prevent backflow into the atria when the ventricles are contracting.

Back 16

mitral

Front 17

Back 17

n

Hint 17

n

Front 18

What vessels are these?

Back 18

n

Hint 18

n

Front 19

What valves are these?

Back 19

n

Hint 19

n

Front 20

What vessels are these?

Back 20

n

Hint 20

n

Front 21

SA Node

Back 21

In right atrium inferior to the entrance to the superior vena cava; provides the stimulus for contraction. Often referred to as pacemaker because it sets the rate of depolarization for the heart as a whole

Hint 21

n

Front 22

AV node

Back 22

In the lower atrial septum at the junction of the atria and ventricles; After impulse arrives at this node atrial contraction happens; at this node the impulse is delayed (0.1 sec) to allow atria to complete contraction

Hint 22

n

Front 23

AVBundle/bundle of his

Back 23

located in interventricular septum; conduction velocity increases to highest speed

Hint 23

n

Front 24

Right and Left branches

Back 24

located in interventricular septum

Hint 24

n

Front 25

Purkinje fibers

Back 25

Long strands of barrel-shaped cells called purkinje myocytes which ramify within muscle bundles of the ventricular walls; these fibers are much denser and more elaborate in the left ventricle because of the larger size of this chamber

Hint 25

n

Front 26

ECG

Back 26

the graphic recording of electrical changes(depolarization followed by repolarization) occurring during the cardiac cycle, records voltage and time nothing else;

Hint 26

n

Front 27

Deflection waves

Back 27

Record voltage and time of electrical events of large amounts of muscle tissue- might not allow us to see nodal issues

Abnormalties of deflection waves and changes in time intervals of ECG are useful in detecting myocardial infarcts or problems with the conduction system of the heart

Hint 27

n

Front 28

Tachycardia

Back 28

>100 bpm; prolonged may progress to fibrillation

Hint 28

n

Front 29

Bradycardia

Back 29

Below 60 bpm

in athletes is positive finding because it indicates an increased efficiency of cardiac functioning. Because stroke volume (the amount of blood ejected by a ventricle with each contraction) increases with physical conditioning the heart can contract more slowly and still meet circulatory commands.

Hint 29

n

Front 30

Fibrillation

Back 30

a condition of rapid uncoordinated heart contractions which makes the heart useless as a pump

Hint 30

n

Front 31

Heart block-- Partial AV

Back 31

Seen on ECG: p-r interval longer than0.18 seconds may suggest this and damage to AV node

Hint 31

n

Front 32

Total heart block

Back 32

no impulses are transmitted through the AV node; and the atria and ventricles beat independently of one another- the atria at the SA node rate and the ventricles at their intrinsic rate which is considerably slower.

Hint 32

n

Front 33

Right and left bundle branch block

Back 33

on ECG it is a prolonged QRS complex (norm 0.08 sec); one ventricle is contracting later than the other

Hint 33

n

Front 34

Standard Limb leads: indirect leads

Back 34

electrodes connected to each arm and to the left leg are considered to connect to the triangle vertices

these record the voltages generated in the extracellular fluids surrounding the heart by the ion flows occurring simultaneously in many cells between any two of the connections

Recording using lead I RA-LA is most sensitive to activity occurring horizontally across the heart

Lead II (RA-LL) and lead III (LA-LL) record activity along the vertical axis from the base of the heart to its apex but from different orientations

Front 35

electrodes

Back 35

electric conductor in which electric current enters or leaves

Front 36

Einthoven's law

Back 36

Einthovens triangle- the heart lies in the center of a triangle with sides of equal lengths

Recording connections are made at the vertices (corners) of that triangle

The sum of the voltages of leads I and III equals that in lead II-- Einthoven's law

Hint 36

n

Front 37

Ground (RL)

Back 37

aka earth

Hint 37

n

Front 38

define intrinsic

Back 38

it does not depend on impulses from the nervous system to initiate its contraction and will continue to contract rhythmically even if all nerve connections are severed

Front 39

functional syncytium

Back 39

n

Hint 39

n

Front 40

2 types of controlling systems that exert effects on the heart activity

Back 40

1. Nerves of the ANS: accelerate or decelerate the heartbeat rate depending on which division is activated

2.Intrinsic conduction system/nodal system consisting of specialized noncontractile myocardial tissue; ensures that heart muscle depolarizes in an orderly and sequential manner(from atria to ventricles) and that the heart beats as a coordinated unit

Hint 40

n

Front 41

Sequence of events in intrinsic conduction

Back 41

SA-AV-AV BUNDLE/BUNDLE OF HIS- RIGHT AND LEFT BUNDLE BRANCHES-PURKINJE FIBERS= VENTRICULAR CONTRACTION

Front 42

Depolarization

Back 42

the return of heart muscle cells to resting state following stimulation

Front 43

Damage to the AV node-bundle results in ...

Back 43

partial/total insulation of the ventricles from the influence of the SA node

Front 44

Autorythmic

Back 44

Found throughout the heart; rates of spontaneous depolarization differ

Front 45

p-R interval

Back 45

represents the time between the beginning of atrial depolarization and ventricular depolarization, including the period during which the depolarization wave passes to the AV node, atrial systole, and the passage of the excitation wave to the balance of the conducting system; generally 0.16-0.18 seconds-- A longer interval may suggest a partial AV heart block caused by damage to the AV node

start of p deflection to start of Q deflection

P-r segment: end of p wave to start of Q deflection

Front 46

QRS complex

Back 46

ventricular depolarization and atrial repolarization

duration normally 0.08 sec; if prolonged may indicate R or L bundle branch block in which one ventricle is contracting later than the other

Hint 46

n

Front 47

S-T segment

Back 47

time of ventricular contraction

End of S deflection and start of T wave.

Hint 47

n

Front 48

Q-T Interval

Back 48

Start of Q deflection to end of T wave

This is the period from the beginning of ventricular depolarization through the repolarization which includes the time of ventricular contraction (S-T segment)

HR 70 bpm- interval normally 0.31-0.41 sec; as rate increases this interval becomes shorter and vise versa

Hint 48

n

Front 49

T wave

Back 49

ventricular repolarization

Hint 49

n

Front 50

End T to next R

Back 50

n

Hint 50

n

Front 51

Fossa Ovalis/ foramen ovale

Back 51

n

Front 52

QRS interval

Back 52

the repolarization of the atria is generally obsecured by the large QRS complex

Front 53

P wave

Back 53

atrial depolarization