Electrical Activity and Conduction of the Signal

Flashcards summarizing key terms and concepts related to the electrical activity and conduction system of the heart, based on the provided lecture notes.

Action Potential

A rapid change in membrane potential that leads to muscle contraction in cardiac myocytes.

Pacemaker Cells

Specialized cardiac cells capable of spontaneously depolarizing, initiating heart contraction.

Membrane Potential

The electrical potential difference across a cell membrane, important for impulse transmission.

SA Node

Sinoatrial node; the primary pacemaker of the heart that sets the rhythm for cardiac contraction.

AV Node

Atrioventricular node; a group of cells that electrically connect the atria and ventricles, controlling heart rate.

Ion Channels

Protein channels in cell membranes that regulate the flow of ions, crucial for action potentials.

Sympathetic Innervation

The part of the autonomic nervous system that increases heart rate and conduction through norepinephrine.

Parasympathetic Innervation

The part of the autonomic nervous system that decreases heart rate and conduction through acetylcholine.

Electrocardiogram (ECG)

A test that measures the electrical activity of the heart and is useful for diagnosing various cardiac conditions.

Refractory Period

The period after an action potential during which a cell cannot fire another action potential, ensuring coordinated contractions.

Gap Junctions

Connections between cardiac cells that allow for rapid electrical communication and synchronized contraction.

K1 Potassium Channel

A channel open at resting potential, contributing to potassium permeability in myocytes.

Calcium Influx

The movement of calcium ions into the cell, necessary for muscle contraction in cardiac cells.

Myocyte

A cardiac muscle cell responsible for contraction and generating action potentials.

Phases of Action Potential

The distinct stages (depolarization, plateau, repolarization, and resting) in the cardiac action potential.

Autonomic Nervous System

The part of the nervous system that regulates involuntary functions, including heart rate through sympathetic and parasympathetic branches.

Bundle of His

The pathway through which electrical impulses are transmitted from the AV node to the ventricles.

Purkinje Fibers

Large fibers that rapidly conduct electrical impulses throughout the ventricles, ensuring simultaneous contraction.

Myocardial Ischemia

Inadequate blood flow to the heart muscle, detectable by changes in the ST segment of the ECG.