Lecture on Somatic Nervous System and Skeletal Muscles

These flashcards cover key terms, concepts, and definitions related to the somatic nervous system and skeletal muscles as outlined in the provided lecture notes.

Neuromuscular junction

The site at which a motor neuron and a skeletal muscle fiber meet, facilitating the transmission of signals for muscle contraction.

Acetylcholine

A neurotransmitter released at the neuromuscular junction that binds to nicotinic receptors on muscle fibers, triggering contraction.

Excitation-contraction coupling

The process by which an action potential in a muscle fiber triggers calcium release from the sarcoplasmic reticulum, leading to muscle contraction.

Motor unit

A single motor neuron and all the muscle fibers it innervates.

Acetylcholinesterase

An enzyme that breaks down acetylcholine into acetic acid and choline in the synaptic cleft, terminating the signal.

EPSP

a change in the membrane potential that makes a neuron more likely to fire an action potential.

IPSP

a change in the membrane potential that makes a neuron less likely to fire an action potential.

Sarcoplasmic reticulum

The endoplasmic reticulum of muscle cells, which stores calcium ions critical for muscle contraction.

Transverse tubules

Deep inward extensions of the sarcolemma that penetrate into the muscle fiber, facilitating the conduction of action potentials.

Sliding filament theory

The explanation of how muscles contract through the sliding movement of actin and myosin filaments.

Calcium's role in muscle contraction

Calcium ions bind to troponin, causing a change that allows actin and myosin to interact for muscle contraction.

Power stroke

The movement of the myosin head pulling actin filaments toward the M line during muscle contraction.

Tetany

A sustained muscle contraction resulting from high-frequency stimulation that prevents relaxation.

Fast-twitch muscle fibers

Type II muscle fibers that primarily use anaerobic metabolism for quick bursts of energy.

Slow-twitch muscle fibers

Type I muscle fibers that use aerobic metabolism, suitable for endurance activities.

Anaerobic respiration

A type of respiration that occurs without oxygen, primarily in fast-twitch fibers during intense exercise.

Aerobic respiration

A type of respiration that occurs with oxygen, primarily in slow-twitch fibers for long-duration activities.