Muscle Contraction and Related Concepts

Flashcards covering key concepts about muscle contraction, related physiological processes, and changes in muscle state.

Muscle Contraction Initiation

The process begins when an impulse reaches the neurotransmitter terminal and spreads to the sarcolemma.

Sarcoplasmic Reticulum

An organelle that releases Ca++ into the sarcoplasm upon receiving an electrical impulse, crucial for muscle contraction.

ATP Role in Muscle Contraction

ATP is required for both the release of Ca++ and for muscle contraction and relaxation processes.

Myofibrils

Structures in muscle fibers that contract due to the interaction between actin and myosin myofilaments.

Muscle Fiber Relaxation

Occurs when the nerve impulse dies down, Ca++ is pumped back into the sarcoplasmic reticulum, and requires ATP.

Rigor Mortis

A state of muscle stiffness due to lack of ATP after death, preventing relaxation.

Hypertrophy

The increase in size of individual muscle cells as a result of exercise.

Atrophy

The decrease in size of muscle after reaching normal adult size, which can be due to disuse or nerve injury.

Tetany

A continuous state of muscle contraction, which can be caused by conditions like low blood Ca.

Fatigue

Decreased work capacity in muscles due to depletion of ATP and oxygen.

Muscle Tone

Slight muscle tautness at rest, influenced by continuous low-level nervous stimulation.