GAP Ch10 Muscle Tissue

Muscle Tissue

One of the four primary tissue types in the body, including skeletal, smooth, and cardiac muscle.

Skeletal Muscle

Muscle tissue that is striated and under voluntary control, responsible for moving the skeleton.

Smooth Muscle

Non-striated muscle tissue that is involuntary, found in the walls of hollow organs.

Cardiac Muscle

Striated and involuntary muscle tissue found only in the heart, coordinated for contraction.

Excitability

The ability of muscle plasma membranes to change their electrical states and propagate action potentials.

Striations

Visible patterns of contractile proteins in skeletal and cardiac muscle tissues.

Muscle Fibers

Individual muscle cells that can also be referred to as muscle cells.

Multinucleated

Condition of skeletal muscle cells having multiple nuclei per cell.

Endomysium

The innermost connective tissue layer surrounding each muscle fiber.

Perimysium

The middle connective tissue layer surrounding muscle fascicles.

Epimysium

The outermost layer of connective tissue wrapping an entire skeletal muscle.

Motor Neuron

A neuron that innervates skeletal muscle fibers at the neuromuscular junction.

Action Potential

An electrical signal that travels along a neuron's axon, triggering muscle contraction.

Acetylcholine

A neurotransmitter released at the neuromuscular junction to stimulate muscle contraction.

T Tubules

Invaginations of the sarcolemma that transmit action potentials into the muscle fiber.

Sarcoplasmic Reticulum

Specialized smooth endoplasmic reticulum in muscle cells that stores calcium ions.

Triad

Structure formed by the arrangement of a T tubule and two terminal cisternae.

Crossbridge

The connection formed between actin and myosin during muscle contraction.

Troponin

Regulatory protein in the thin filament that binds calcium ions during contraction.

Tropomyosin

Protein that covers the active sites on actin filaments in a relaxed muscle.

Sliding Filament Model

The mechanism of muscle contraction where thin filaments slide past thick filaments.

Z Line

Structure that anchors the thin filaments and defines the boundaries of each sarcomere.

M Line

The middle line in the sarcomere where thick filaments are anchored.

A Band

The dark band in the sarcomere containing myosin filaments.

I Band

The light band in the sarcomere consisting only of actin filaments.

H Zone

Area of the sarcomere that contains only thick filaments (myosin).

Isotonic Contraction

Muscle contraction where tension remains constant while the muscle shortens or lengthens.

Concentric Contraction

Type of isotonic contraction where the muscle shortens to move a load.

Eccentric Contraction

Type of isotonic contraction where the muscle lengthens while under tension.

Isometric Contraction

Muscle contraction producing tension without changing the length of the muscle.

Creatine Phosphate

Stored form of energy in muscle that can quickly regenerate ATP from ADP.

Glycolysis

Process of breaking down glucose to produce ATP, occurring in anaerobic conditions.

Aerobic Respiration

Metabolic process that produces ATP in the presence of oxygen.

Fast Glycolytic Fibers

Muscle fibers that contract quickly using anaerobic processes and fatigue rapidly.

Slow Oxidative Fibers

Muscle fibers that contract slowly and rely on aerobic respiration.

Fast Oxidative Fibers

Muscle fibers that contract quickly but can use both aerobic and anaerobic respiration.

Hypertrophy

Increase in muscle size due to resistance training and increased myofibril formation.

Intercalated Discs

Special junctions between cardiac muscle cells that facilitate synchronized contractions.

Involuntary Muscle

Muscle types (smooth and cardiac) that are not consciously controlled.

Voluntary Muscle

Muscle type (skeletal) that is under conscious control.

Spindle Shaped

The shape of smooth muscle fibers, thicker in the middle and tapering at the ends.

Dense Bodies

Structures in smooth muscle fibers that anchor actin filaments to the sarcolemma.

Hormonal Control

Triggers for smooth muscle contraction that involve hormones and neural stimulation.