Muscle Tissue Overview

Vocabulary flashcards covering the fundamental concepts and terminology related to muscle tissue.

Skeletal Muscle

Muscle that is attached to bones and responsible for voluntary movement.

Cardiac Muscle

Muscle located in the heart wall, responsible for involuntary contractions.

Smooth Muscle

Muscle found in viscera such as blood vessels and organs, responsible for involuntary movements.

Excitability

The ability of muscle tissue to respond to stimuli, such as neural input.

Contractility

The ability of muscle fibers to shorten or contract in response to stimulation.

Elasticity

The ability of a muscle fiber to return to its original length after contraction.

Extensibility

The ability of a muscle fiber to be stretched beyond its relaxed length.

Body Movement

One of the primary functions of skeletal muscle tissue.

Maintenance of Posture

Skeletal muscles help to maintain the body in a stable position.

Temperature Regulation

Skeletal muscles generate heat as a byproduct of muscle activity, helping to maintain body temperature.

Storage of Materials

Skeletal muscles assist in storing and moving materials within the body.

Support

Skeletal muscles provide support to the body and protect internal organs.

Sarcoplasm

The cytoplasm of a muscle cell that contains myofibrils and myofilaments.

Myofibril

Cylindrical structures within muscle fibers that extend the entire length of the cell.

Epimysium

The connective tissue layer that surrounds the entire muscle.

Fasciculus

A bundle of muscle fibers within a muscle.

Endomysium

The connective tissue that surrounds individual muscle fibers.

Sarcolemma

The plasma membrane of a muscle cell.

Nuclei

Muscle fibers are multinucleated; they contain multiple nuclei within a single muscle fiber.

Tendon

The structure that attaches muscle to bone.

Perimysium

The connective tissue that surrounds individual fascicles within a muscle.

Muscle Belly

The thick middle part of a muscle.

Sarcomere

The functional contractile unit of a muscle, organized between two Z discs.

Actin

Thin myofilaments involved in muscle contraction.

Myosin

Thick myofilaments that bind to actin during muscle contraction.

H Zone

The region in the sarcomere that contains only thick filaments.

M Line

The center line of the sarcomere that anchors thick filaments.

Z Line

The boundaries of the sarcomere where thin filaments attach.

Titin

A large protein that stabilizes the thick filament and aids in muscle elasticity.

Tropomyosin

A protein that covers myosin-binding sites on actin.

Troponin

A regulatory protein that moves tropomyosin when it binds calcium ions.

Sliding Filament Theory

Describes how muscle contraction occurs through the sliding of actin over myosin filaments.

Neuromuscular Junction

The site where a motor neuron communicates with a muscle fiber.

Synaptic Knob

The expanded end of a motor neuron that contains synaptic vesicles.

Synaptic Vesicles

Sacs filled with the neurotransmitter acetylcholine (ACh).

Motor End Plate

The region of the sarcolemma that contains receptors for acetylcholine.

Synaptic Cleft

The space between the synaptic knob and the motor end plate.

Acetylcholinesterase (AChE)

An enzyme that breaks down acetylcholine in the synaptic cleft.

Calcium Ions (Ca2+)

Ions released from the sarcoplasmic reticulum that trigger muscle contraction.

Motor Unit

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

All-or-None Principle

The principle stating that a muscle fiber contracts fully or not at all.

Transverse (T) Tubules

Protrusions of the sarcolemma that spread excitation into the muscle cell.

Sarcoplasmic Reticulum

The endoplasmic reticulum in muscle cells, responsible for calcium ion storage.

Muscle Fiber

An individual muscle cell.

Myofilaments

The contractile proteins within myofibrils, including actin and myosin.

A Band

The dark region of the sarcomere that contains the length of myosin filaments.

I Band

The light region of the sarcomere that contains only thin filaments.

H Zone

The area within the A band where there are no thin filaments present.

Sarcomere Components

Includes thick and thin filaments organized into functional units.

Components of Sarcomere

Include Myosin, Actin, Tropomyosin, and Troponin.

Skeletal Muscle Composition

Composed of fascicles, muscle fibers, myofibrils, and myofilaments.

Fascicles

Bundles of muscle fibers arranged within a skeletal muscle.

Myofibrils Structure

Cylindrical structures that contract to produce movement.

Thin Filament Component

Primarily composed of actin, which is involved in muscle contraction.

Thick Filament Component

Primarily composed of myosin, which interacts with actin during contraction.

M Line Function

Maintains alignment of thick filaments within the sarcomere.

Z Disc Role

Serves as the anchor point for thin filaments.

Contraction Mechanics

Involves the interaction of myosin and actin during muscle shortening.