Anatomy Unit 3 (7, 8 & 9)[54]

Epimysium

The outermost layer of connective tissue surrounding a muscle.

Perimysium

The connective tissue that surrounds bundles of muscle fibers (fasciculus).

Endomysium

The innermost layer of connective tissue that surrounds individual muscle fibers.

Fasciculi

Bundles of muscle fibers within a muscle.

Sarcomere

The basic contractile unit of a muscle fiber.

Parallel Fasciculi Arrangement

Fascicles run parallel to the muscle’s long axis; e.g., sartorius.

Circular Fasciculi Arrangement

Fascicles form concentric rings around openings; e.g., orbicularis oris.

Fusiform Fasciculi Arrangement

Spindle-shaped muscles tapering at both ends; e.g., biceps brachii.

Convergent Fasciculi Arrangement

Fascicles converge from a broad origin to a tendon; e.g., pectoralis major.

Unipennate Fasciculi Arrangement

Fascicles attach to one side of a tendon; e.g., extensor digitorum longus.

Bipennate Fasciculi Arrangement

Fascicles attach to both sides of a tendon; e.g., rectus femoris.

Multipennate Fasciculi Arrangement

Fascicles converge on several tendons; e.g., deltoid.

Frontalis Muscle

Muscle that allows blinking and closing eyes.

Temporalis Muscle

Muscle involved in mastication (chewing).

Sternocleidomastoid Muscle

Muscle that rotates and flexes the neck.

Rotator Cuff

Group of muscles that stabilize the shoulder.

Prime Mover

The main muscle responsible for a specific movement.

Synergist

A muscle that assists the prime mover.

Antagonist

A muscle that opposes the action of the prime mover.

Concentric Muscle Contraction

Muscle shortens while generating force.

Eccentric Muscle Contraction

Muscle lengthens while controlling force.

Isometric Muscle Contraction

Muscle generates force without changing length.

Slow Oxidative Fiber Type

Muscle fibers suited for endurance activities.

Fast Glycolytic Fiber Type

Muscle fibers adapted for short bursts of power.

Fast Oxidative Fiber Type

Muscle fibers combining speed and endurance.

Dendrites

Parts of a neuron that receive input signals.

Axon

Part of a neuron that transmits output signals.

Astrocytes

Glial cells that maintain the blood-brain barrier and support neurons.

Oligodendrocytes

Glial cells in the CNS that form the myelin sheath around axons.

Schwann Cells

Glial cells in the PNS that myelinate axons and aid in nerve repair.

Neuromuscular Junction

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

Neurotransmitter Receptors

Found on the postsynaptic membrane, they bind neurotransmitters to initiate a response.