PSIO 201 Muscular System Flashcards

Skeletal Muscle

Muscle tissue that contracts voluntarily to facilitate movement.

Cardiac Muscle

Involuntary muscle tissue found only in the heart, responsible for pumping blood.

Smooth Muscle

Involuntary muscle tissue found in the walls of hollow organs, responsible for regulating internal processes.

Muscle Contraction

The process where muscle fibers shorten and generate tension.

Origin

The fixed attachment point of a muscle to a bone.

Insertion

The movable attachment point of a muscle to a bone.

Agonist

The muscle that is primarily responsible for a specific movement.

Antagonist

The muscle that opposes the action of the agonist.

Synergist

A muscle that assists the agonist in a movement.

Fixator

A type of synergist that stabilizes the origin of the agonist.

Flexion

A bending movement that decreases the angle between two parts.

Extension

A straightening movement that increases the angle between two parts.

Abduction

Movement away from the midline of the body.

Adduction

Movement toward the midline of the body.

Muscle Fiber

Individual muscle cells, also called muscle fibers.

Myofibrils

Long filaments found within muscle fibers that are responsible for muscle contraction.

Sarcoplasmic Reticulum (SR)

A specialized cell organelle that stores calcium ions and regulates calcium concentration.

Calcium Ions (Ca2+)

Essential ions that play a key role in muscle contraction.

Crossbridge Cycle

Process where myosin heads bind to actin, pulling the thin filament and causing contraction.

Rigor Mortis

Postmortem stiffness due to lack of ATP in muscle tissue.

Cori Cycle

The process by which lactate produced in muscles is converted back to glucose in the liver.

Motor Unit

A motor neuron and all the muscle fibers it innervates.

Tetanus

Sustained muscle contraction resulting from rapid stimulation.

Isometric Contraction

Muscle contraction without a change in length.

Isotonic Contraction

Muscle contraction with a change in length.

Hypertrophy

Increase in muscle size due to exercise.

Atrophy

Decrease in muscle size due to disuse or aging.

ATP (Adenosine Triphosphate)

The main energy currency in cells, necessary for muscle contraction.

Creatine Phosphate

A storage form of high-energy phosphate used to regenerate ATP.

Anaerobic Glycolysis

Breakdown of glucose in the absence of oxygen to generate ATP.

Aerobic Metabolism

The process of producing cellular energy involving oxygen.

Fatigue

The decline in ability of a muscle to generate force.

Mitochondria

Organelles responsible for ATP production through oxidative phosphorylation.

Somatic Nervous System

The part of the peripheral nervous system associated with voluntary control of body movements.

Sarcoplasm

The cytoplasm of a muscle fiber.

T-Tubules

Transverse tubules that help conduct electrical impulses deep into muscle fibers.

Sarcomere

The basic contractile unit of muscle tissue.

Thick Filaments

Composed mainly of myosin, responsible for muscle contraction.

Thin Filaments

Composed mainly of actin, play a role in muscle contraction.

Troponin

A regulatory protein that binds calcium and helps control muscle contraction.

Tropomyosin

A regulatory protein that blocks the myosin-binding sites on actin.

Z Disc

The boundary of a sarcomere where actin filaments are anchored.

A Band

The dark area of a sarcomere, containing thick filaments.

I Band

The light area of a sarcomere, containing thin filaments.

H Zone

The region within the A band where there are only thick filaments.

Z Line

The line that marks the borders of each sarcomere.

Sliding Filament Theory

Theory that explains muscle contraction by the sliding of thin filaments (actin) over thick filaments (myosin).

Pacemaker Cells

Cells in the heart responsible for initiating electrical impulses.

Intercalated Discs

Specialized connections between cardiac muscle cells for coordinated contraction.

Gap Junctions

Intercellular connections that allow for electrical continuity between cardiac muscle cells.

Autorhythmicity

The ability of the heart to generate its own rhythm.

Visceral Smooth Muscle

Type of smooth muscle that lines the walls of hollow organs.

Multiunit Smooth Muscle

Type of smooth muscle consisting of individual fibers that function independently.

Calmodulin

A calcium-binding protein that regulates smooth muscle contraction.

Density of Capillaries

An important factor in muscle endurance, increased by endurance training.

Myoglobin

An oxygen-binding protein found in muscle tissue.

Lactic Acid

A byproduct of anaerobic metabolism, associated with muscle fatigue.

Glycogen

Stored form of glucose in muscles, used for energy during contraction.

Endurance Training

Exercise focused on improving stamina and aerobic capacity.

Strength Training

Exercise focused on increasing muscle strength and hypertrophy.

Muscle Regeneration

The process by which muscle fibers repair and grow following injury.

Satellite Cells

Cells that assist in muscle repair and regeneration.

Longitudinal Muscle

Muscle fibers arranged parallel to the direction of muscle tension.

Circumferential Muscle

Muscle fibers arranged circularly around an opening or cavity.

Concentric Contraction

Muscle shortening while generating tension.

Eccentric Contraction

Muscle lengthening while generating tension.

Power Stroke

The action of myosin pulling actin during muscle contraction.

Motor End Plate

The region of the muscle fiber's plasma membrane that is specialized for neuromuscular junction signaling.

Acetylcholine (ACh)

A neurotransmitter used by motor neurons to stimulate skeletal muscle contraction.

Skeletal Muscle Fiber Types

Includes slow oxidative (SO), fast glycolytic (FG), and fast oxidative-glycolytic (FOG) fibers.

Fatigability

The relative ease with which muscles tire during exertion.

Imbalance of Electrolytes

A common cause of muscle cramps and fatigue.

Muscle Recruitment

The process of activating additional motor units to increase muscle force.

Calcium Pump

A membrane protein that actively transports calcium ions back into the SR.

Action Potential

A temporary reversal of the electrical potential along the membrane of a neuron or muscle cell.

Neuromuscular Junction (NMJ)

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

Exercise Adaptations

Changes in muscle structure and function due to training.

Blood Flow during Exercise

Increased blood flow to muscles during exercise enhances oxygen delivery and waste removal.

Oxygen Debt

The amount of oxygen required after physical exercise to restore the body to its resting state.

Body Posture Control

The ability to maintain an upright position using muscle tone and balance.