Muscular System and Cardiac Physiology

These flashcards cover key terms and concepts related to the muscular system and cardiac physiology, based on lecture notes.

Motion

The function of muscles to move the body from place to place, including peristalsis in smooth muscles.

Stabilizing Body Position

The capability of muscles to stabilize body position and joints.

Thermogenesis

The generation of heat as a byproduct of muscle contraction, requiring ATP.

Excitability

The property of muscle tissue that allows it to respond to stimulation by nerves.

Contractability

The ability of muscle tissue to contract.

Extensibility

The capability of muscle tissue to be stretched without being damaged.

Elasticity

The ability of muscles to return to their normal shape after being stretched.

Sarcoplasm

The cytoplasm of muscle fibers, containing myoglobin.

Myofibrils

Thread-like structures within muscle fibers that are responsible for muscle contraction.

Sarcomere

The functional unit of a muscle fiber, defined as the smallest contractile unit.

Myosin

A thick filament protein in muscle cells known for its rod-like tail and heads that bind to actin.

Actin

A protein that forms thin filaments and has binding sites for myosin in muscle contraction.

Tropomyosin

A string-like protein that blocks active sites on actin molecules.

Troponin

A protein that binds to tropomyosin and calcium ions in muscle contractions.

Neuromuscular Junction

The synapse between a motor neuron and a muscle fiber where nerve impulses trigger muscle contraction.

Action Potential

An electrical signal that travels along the sarcolemma to initiate muscle contraction.

Cardiac Muscle

Specialized muscle found in the heart, characterized by intercalated discs and unique contraction properties.

Atria

The upper chambers of the heart that receive blood.

Ventricles

The lower chambers of the heart that pump blood out of the heart.

Systole

The phase of the heartbeat when the heart muscle contracts and pumps blood.

Diastole

The phase when the heart muscle relaxes and the chambers fill with blood.

Fibrillation

A rapid and irregular contraction of the heart muscle.

Cardiac Output

The amount of blood pumped by each ventricle in one minute.

Stroke Volume

The amount of blood ejected by a ventricle with each heartbeat.

Vascular Resistance

The resistance that must be overcome to push blood through the circulatory system.

Veins

Blood vessels that carry deoxygenated blood towards the heart, featuring valves that prevent backflow.