Anatomy & Physiology - Cardiac Contractile Cells

Vocabulary flashcards for key terms related to cardiac muscle anatomy, physiology, and electro-mechanical coupling.

Cardiomyocytes

Structural components of the heart responsible for its contractile function.

Resting Membrane Potential

The electrical potential of a cell membrane in a non-excited state.

E-C Coupling

The process by which an electrical stimulus triggers a mechanical response (contraction) in cardiomyocytes.

Intercalated Discs

Specialized structures that connect cardiac myocytes, containing desmosomes and gap junctions.

Desmosomes

Hold cardiac myocytes together within the intercalated discs.

Gap Junctions

Permit the flow of local current (ions) between adjacent cardiac myocytes, facilitating action potential propagation.

Autorhythmic Cells

specialized cells within the heart that spontaneously generate action potentials, dictating heart rate

Integral Proteins

Extend into or through the lipid bilayer of a cell membrane that are firmly embedded.

Peripheral Proteins

Loosely attached to the internal or external surfaces of the lipid bilayer.

Ion Channels

Includes leak channels, voltage-gated channels and ligand-gated channels which facilitate the movement of ions across the cell membrane.

Membrane Pumps

Active transport proteins like the Na+/K+ pump that maintain ion gradients across the cell membrane.

Polarized Membrane

Maintains a resting membrane potential where the inside of the cell is negative compared to the outside.

Ca2+-induced Ca2+ release

The process where influx of extracellular Ca2+ induces the release of Ca2+ from the sarcoplasmic reticulum by binding to Ryanodine receptor (RyR).

Action Potential

Sequence of rapidly occurring events where the membrane potential reverses and returns to its original state.

Refractory Period

Period of time during which a second action potential cannot be triggered

Tetanic Contraction

Sustained muscle contraction due to high-frequency stimulation; does not occur in cardiac muscle due to long refractory period