Test 2

Sinoatrial node (S.A Node)

Chief pacemaker. (60-100). Located in the right atrium

Internodal fibers

Between sinoatrial node and atrioventricular node

Atrioventricular node (A.V Node)

backup for sinoatrial node. (40-60). Floor of right atrium.

A. V. Bundle (Bundle of His)

(40-60 bpm). Below AV junction

Left bundle branch has 2 fascicles (40-60)

Anterior and posterior fascicle

Purkinje fibers

20-40 bpm

Automaticity

Ability of the heart to initiate electrical impulses without being stimulated

Conductivity

Ability of the heart cells to receive and transmit an electrical impulse

Contractility

Ability of the heart muscles to shorten in respond to an electrical impulse

Excitability (Irritability)

Ability of the heart cells to respond to an impulse or stimulus

Main intracellular cation

Potassium (K)

Main extracelluar cation

Sodium (Na)

Inside of cell charge while in relaxation stage

Negative

Depolarization & contraction

When Sodium & potassium mix inside the cell

repolarization & relaxation

Sodium is kicked out of the cell

*Which is an electrical event

Depolarization

*Location of AV node

Bottom of right atrium

The Autonomic nervous system can be divided into

Sympathetic (Fight flight/adrenaline) & Parasympathetic (rest & digest/fleed & breed)

*Sympathetic Nervous System

The branch of the ANS that increases heart rate

*Parasympathetic nervous system

The branch of the ANS that helps slow the heart rate

Hypokalemia

Decreased heart rate

Hyperkalemia

Increased heart rate

Hypocalcemia

Decrease in the force of heart contractions

Hypercalcemia

increase in the force of heart contractions