Electrical Properties of the Heart and Conduction System Flashcards Preview

Circulatory System > Electrical Properties of the Heart and Conduction System > Flashcards

Flashcards in Electrical Properties of the Heart and Conduction System Deck (41):
1

SA Node

Sinoatrial Node. Normal site of origin of the electrical impulse. The hearts natural pacemaker. SA node travels through the right and left atria resulting in the atrial contraction.

2

AV Node

Atriocentricular node. Transiently slows electrical impulse.

3

Bundle of His

A continuation of the AV node. Bundle branches procede the Bundle of His.

4

Pukinje Fibers

Fibers that go to the left and right ventricles.

5

Excitability

The ability of cells to respond to electrical impulses.

6

Conductivity

The ability of cells to conduct electrical impulses.

7

Intrinsic Automaticity

The ability to generate an impulse to contract without the need of a nerve stimulus. (CARDIAC CELLS)

8

Chronotropic State

Hearts rate of contraction (monitored by various systems in the body)

9

Dromotropic State

Hearts rate of electrical conduction (monitored by various systems in the body)

10

Inotropic State

Hearts strength of contraction (monitored by various systems in the body)

11

Chemoreceptors

Detect chemical changes in the blood.

12

Baroreceptors

Sense the pressure in the heart or arteries.

13

Contractility

Strength of heart muscle contraction.

14

Parasympathetic Stimulation

Slows heart by affecting AV node

15

Sympathetic Stimulation

Alpha OR Beta effects; depending on what nerve receptor is stimulated.

16

ALPHA effects

Alpha receptors are stimulated resulting in vasoconstriction

17

BETA effects

Beta receptors are stimulated resulting in increased inotropic,dromotropic, and chronotropic states.

18

Epinephrine

Hormone that has a greater stimulatory effect on BETA receptors.

19

Norepinephrine

Hormone that has a greater stimulatory effect on ALPHA receptors.

20

Electrolytes

IONS. Charged chemicals.

21

Na+

Sodium. Concentration is greater OUTSIDE of the cell.

22

K+

Potassium. Concentration is greater INSIDE of the cell.

23

Ca2+

Calcium.

24

Electrical Potential

Cellular Electrical Charged difference across the membrane. Measured in Millivolts.

25

Resting Cell

Negative Electrical Pote - Extracellular space is more positively charged than the intracellular space.

26

Polarized State

Resting cells normally have a NET negative charge with respect to the outside of the cell.

27

Depolerization

Heart cell gets a stimulus from the conduction system. Sodium (Na+) rushes in, along with some calcium (Ca2+). Changing the charge of the cell. Makes the intracellular slightly positive charged.

28

Repolarization

The process in which the cell can get back to the POLERIZED state (net negative).Depolerization slows down...Potassium (k+) starts to flow out of the cell, and the sodium potassium pump starts to activate based on the charge needs of the cell to keep it at a polarized state (net negative).

29

Absolute Refractory Period

EARLY phase of repolarization when the cell contains a large concentration of ions that it cannot be stimulated to depolerize.

30

Relative Refractory Period

LATE stage of repolarization, cells are able to respond to a stronger stimulus.

31

ECG

Electrocardio gram a graphic recording of the electrical activity of the heart

32

P wave

Occurs first. Represents the electrical impulse through the atria

33

P-R

Flat line between the p and r... Represents the time delay within the AV node

34

QRS

QRS complex. Represents the DEPOLARIZATION of the ventricle contraction.

35

ST segment

The pause after the QRS complex. This is where repolarization is beginning.

36

T

Represents completion of REPOLARIZATION.

37

Cardiac Cycle

From contraction of the myocardium to the next contraction

38

Systole

Ventricular contraction. Blood is pumped to the body (systemic) and lungs (pulmonary) via contraction of the ventricles.

39

Afterload

Pressure in the AORTA.

40

Stroke volume

Amount of blood ejected into the aorta from the left ventricle per contraction

41

Cardiac output

Expressed as the volume of blood pumped through the circulatory system in one minute. LITERS PER MINUTE

Heart rate X stroke volume = cardiac output (lpm)