Muscles and Muscle Tissue

A set of flashcards covering key vocabulary terms and definitions related to muscle types, functions, and physiology.

Skeletal Muscle

Muscle type associated with the bony skeleton, consisting of large cells that bear striations and are under voluntary control.

Cardiac Muscle

Muscle type found only in the heart, consisting of small striated cells that are under involuntary control.

Smooth Muscle

Muscle type found in the walls of hollow organs, consisting of small, elongated, unstriated cells that are under involuntary control.

Excitability

The ability of muscle tissue to receive and respond to a stimulus.

Contractility

The ability of muscle tissue to contract forcibly when stimulated.

Extensibility

The ability of muscle tissue to be stretched.

Elasticity

The ability of muscle tissue to resume its original length once stretched.

Muscle Functions

Includes producing movement, maintaining posture, stabilizing joints, and generating heat.

Sarcoplasmic Reticulum

A smooth endoplasmic reticulum in muscle fibers that regulates the availability of calcium ions.

T Tubules

Infoldings of the sarcolemma that run between terminal cisterns of the sarcoplasmic reticulum.

Neuromuscular Junction

The connection between an axon terminal of a motor neuron and a muscle fiber, where electrical stimulation occurs.

Acetylcholine (ACh)

A neurotransmitter released at the neuromuscular junction, which binds to receptors on the muscle cell.

Sliding Filament Model

Describes how muscle contraction occurs as thin filaments slide past thick filaments, shortening the sarcomere.

Cross Bridge Cycle

The series of events in muscle contraction where myosin heads bind to actin, pivot, and pull the actin filaments.

Lactic Acid

A byproduct of anaerobic glycolysis, which contributes to muscle soreness after exercise.