Skeletal Muscles

Flashcards to review key vocabulary and concepts related to skeletal muscles from the nursing science lecture.

Skeletal Muscle

Muscle type characterized by striations and voluntary control, primarily responsible for body movement.

Excitability

The ability of muscle tissue to respond to stimuli, such as nerve signals.

Contractility

The capacity of muscle tissue to shorten and generate force during movement.

Extensibility

The ability of muscle tissue to be stretched and return to its original length.

Endomysium

A thin connective tissue layer that surrounds individual muscle fibers.

Perimysium

A connective tissue sheath that wraps around groups of muscle fibers, forming fascicles.

Epimysium

A coarse connective tissue that encases the entire muscle.

Calcium ions (Ca+)

Essential ions that trigger muscle contraction by interacting with troponin.

Neuromuscular junction (NMJ)

The synapse between a motor neuron and a skeletal muscle fiber.

Acetylcholine (ACh)

The neurotransmitter released at the NMJ that initiates muscle contraction.

Troponin

A protein that binds calcium ions and regulates muscle contraction by moving tropomyosin.

Sliding filament model

The understanding of muscle contraction in which myosin heads pull actin filaments, causing shortening of the muscle.

Prime mover (Agonist)

The main muscle responsible for producing a specific movement.

Antagonist

A muscle that opposes the action of the prime mover.

Synergists

Muscles that assist the prime mover in performing a movement.

Fixator Muscles

Muscles that stabilize a joint and maintain posture and balance during movement.

Adenosine Triphosphate (ATP)

The primary energy carrier in cells, crucial for muscle contraction.

Sarcoplasmic Reticulum (SR)

The organelle in muscle cells responsible for calcium ion storage and release.

Myofibrils

Long, threadlike structures composed of myofilaments, responsible for muscle contraction.

Myofilaments

The filaments (actin and myosin) that make up myofibrils and with sliding action, facilitate muscle contraction.

Depolarization

The process by which the inside of a cell becomes more positively charged, typically due to sodium ion influx.

Repolarization

The return of a cell's membrane potential to a negative value after depolarization, primarily due to potassium ion efflux.