Muscle Anatomy and Physiology

40 flashcards covering key concepts related to muscle anatomy and physiology, using vocabulary definitions and explanations.

Myasthenia Gravis

A condition causing extreme muscle weakness due to damaged receptor sites on muscle membranes.

Curare

A neuromuscular blocking agent that promotes muscle relaxation and paralysis during surgery by blocking receptor sites.

Diaphragm

The chief muscle of respiration.

Intercostal muscles

Muscles that depress the ribs during expiration.

Sartorius

The longest muscle in the body, aiding in the flexion of the hip and knee, and in abducting and laterally rotating the thigh.

Masseter

The muscle responsible for chewing and closing the jaw.

Orbicularis Oculi

The muscle that encircles and closes the eyes, allowing for winking and blinking.

Zygomaticus

The muscle primarily responsible for smiling and laughing.

Frontalis

The muscle that raises the eyebrows.

Sternocleidomastoid

A muscle that contracts to cause flexion and rotation of the head.

Quadriceps Femoris

The most powerful group of muscles responsible for leg extension, consisting of four muscles.

Pectoralis

Muscle that moves the upper arm across the front of the chest; involved in flexion and adduction.

Biceps Brachii

Muscle that flexes the forearm.

Triceps Brachii

The prime mover when extending the forearm; supports weight during push-ups.

Deltoid

Muscle that abducts the arms to a horizontal position and is an intramuscular injection site.

Sliding filament theory

Theory explaining muscle contraction through the interaction of actin and myosin in the sarcomere.

Sarcomere

The basic contracting unit of muscle fibers.

Calcium

Essential mineral required for muscle contraction and stored in the sarcoplasmic reticulum.

ATP

Molecule required for energy during muscle contraction.

Neuromuscular Junction (NMJ)

The synapse connecting an axon terminal to a muscle cell membrane.

ACh (Acetylcholine)

A neurotransmitter that plays a role in muscle contraction.

Acetylcholinesterase

An enzyme that breaks down acetylcholine after it has acted on the synapse.

Recruitment

The addition of motor units to increase the force of muscle contraction.

Motor Unit

A single nerve that innervates a group of muscle cells.

Tetanus

A sustained muscle contraction resulting from repeated stimulation.

Twitch

A single muscle contraction followed by relaxation.

Muscle Tone

The normal continuous state of partial muscle contraction.

Myalgia

Muscle pain.

Muscle Naming

Skeletal muscles are named based on size, shape, fiber direction, location, origins, and insertions.

Muscle Fiber Structure

Includes the sarcolemma, sarcoplasm, myofibrils, sarcoplasmic reticulum, and T-tubules.

Atrophy

Wasting of muscle due to disuse or denervation.

Hypertrophy

Growth of muscle in response to overuse.

Contracture

Abnormal fibrous formation in muscle causing it to freeze in a flexed position.

Fascia

Outer layer of fibrous connective tissue surrounding muscle.

Tendon

Connective tissue that links muscle to bone.

Antagonist

Muscles that oppose actions; e.g., when biceps contract, triceps relax.

Synergist

Muscles that work together for a specific action.

Cardiac Muscle

Involuntary, striated muscle found only in the heart.

Skeletal Muscle

Voluntary muscle attached to bone, responsible for movement and posture.

Smooth Muscle

Unstriated, involuntary muscle that lines organs and allows for slow, sustained contractions.