Skeletal Muscle Anatomy and Physiology

These flashcards cover key terms and concepts related to skeletal muscle anatomy, function, and various physiological processes.

Skeletal Muscle Tissue

Tissue that contracts to move the body by pulling on bones of the skeleton.

Cardiac Muscle Tissue

Tissue that contracts in the heart to propel blood through the blood vessels.

Smooth Muscle Tissue

Tissue that contracts to move fluids and solids along the digestive tract and regulate artery diameters.

Epimysium

Dense layer of collagen fibers surrounding the entire muscle.

Perimysium

Fibrous layer that divides muscle into compartments or bundles of cells known as fascicles.

Endomysium

Connective tissue that surrounds individual muscle cells or fibers, containing capillaries and nerve fibers.

Myoblasts

Muscle-forming cells that fuse to form multinucleate skeletal muscle fibers.

Sarcoplasm

Cytoplasm of a muscle fiber, includes glycogen for ATP synthesis and myoglobin for oxygen storage.

Sarcoplasmic Reticulum (SR)

Membranous sacs that encircle each myofibril and store calcium ions for muscle contraction.

Neuromuscular Junction (NMJ)

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

Twitch

A single stimulus-contraction-relaxation cycle in a muscle fiber.

Calcium Ion Role

Triggers muscle contraction by binding to troponin, causing a change that exposes the active sites on actin.

Sliding Filament Theory

Explains how muscle contractions occur through the sliding of thin filaments past thick filaments.

Tropomyosin

Regulatory protein that covers the active sites on actin to prevent myosin from binding during relaxation.

Troponin

Regulatory protein with three subunits that bind calcium and help facilitate muscle contraction.

Fast Muscle Fibers

Fibers that reach peak tension quickly, have large diameters, and produce rapid but short bursts of force.

Slow Muscle Fibers

Fibers that contract more slowly, have a higher stamina, and primarily use aerobic metabolism.

Intermediate Muscle Fibers

Fibers that share characteristics of both fast and slow fibers, are more fatigue resistant.

Muscle Fatigue

Condition when a muscle can no longer perform at the required activity level due to various factors.

Cori Cycle

The metabolic pathway in which lactate produced in muscles is converted back to glucose in the liver.