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Layer of connective tissue that surrounds an individual muscle fiber.


Layer of connective tissue that surrounds a skeletal muscle.


Connective tissue located between adjacent muscles.


Protein found within thick filament.


A small bundle of muscle fibers.


Layer of connective tissue that separates a muscle into small bundles called fascicles.


Cell membrane of a muscle fiber.


Unit of alternating light and dark striations between Z lines.


Cytoplasm of a muscle fiber.

Sarcoplasmic reticulum

Cellular organelle in muscle fiber corresponding to the endoplasmic reticulum.


Cordlike part that attaches a muscle to a bone.

Transverse (T) tubule

Membranous channel extending inward from muscle fiber membrane.


Star-shaped neuroglia between neurons and blood vessels.


Nerve fiber arising from a slight elevation of the cell body that conducts an impulse away from the cell body.

Chromatophilic substance (Nissl bodies)

Corresponds to rough endoplasmic reticulum in other cells.


Branch of an axon.


Neuron process with many branches that conducts an impulse toward the cell body.

Myelin Sheath

Substance of Schwann cell composed of lipoprotein that insulates axons and increases impulse speed.


Sheath of Schwann cell containing cytoplasm and nucleus that encloses myelin.


Netowrk of fine threads extending into nerve fiber.


Structure capable of responding to motor impulse.

Ependymal Cell

Cells that cover the inside spaces of the brain ventricles and help regulate cerebrospinal fluid.


Specialized mass of neuron cell bodies outside the brain or spinal cord.


Transmits impulse from sensory to motor neuron withing central nervous system.


Phagocytic neuroglia.

Motor (efferent) neuron

Transmits impulse out of the brain or spinal cord to effectors (muscles and glands).


Myelin-forming neuroglia in brain & spinal cord.

Sensory (afferent) neuron

Transmits impulse into brain or spinal cord from receptors.

31 pairs

Number of spinal nerves in the spinal cord.

Cervical enlargement

The bulge in the spinal cord that gives off nerves to the upper limbs.

Lumbar enlargement

The bulge in the spinal cord that gives off nerves to the lower limbs.

Posterior median sulcus

A groove that extends the length of the spinal cord posteriorly.

Posterior horns

Resemble the upper wings of a butterfly (in a spinal cord cross section).

Anterior horns

Where the cell bodies of motor neurons are found in the spinal cord.

Gray commissure

Connects the gray matter on the left and right sides of the spinal cord.

Central canal

Found in the gray commissure of the spinal cord & contains cerebrospinal fluid & is continuous with the ventricles of the brain.

Anterior, lateral, & posterior funiculi

The divisions of the spinal cord's white matter.

Nerve tracts

The longitudinal bundles of nerve fibers within the spinal cord comprise these major nerve pathways.

Central sulcus

Separates frontal & parietal lobes.

Cerebral Cortex

Thin layer of gray matter on surface of cerebrum.

Corpus callosum

Connects cerebral hemispheres.

Falx cerebelli

A layer of dura mater that separates cerebellar hemispheres.

Gyrus (convolution)

Ridge on surface of cerebrum.


Part of diencephalon that forms lower walls and floor of third ventricle.


Cerebral lobe located deep within lateral sulcus.

Medulla oblongata

Part of brainstem continuous with the spinal cord.


Part of brainstem between diencephalon and pons.

Optic chiasma

Structure formed by the crossing-over of the optic nerves.

Pineal gland

Cone-shaped structure attached to upper posterior portion of diencephalon.


Rounded bulge on underside of brainstem.

Auditory tube

Connects middle ear & pharynx.

Ceruminous gland

Wax-secreting structure.

External acoustic meatus

S-shaped tube leading to tympanic membrane.


Auditory ossicle attached to tympanic membrane.

Membranous labyrinth

Contains endolymph.

Osseous (bony) labyrinth

Bony canal of inner ear in temporal bone.

Scala tympani

Extends from apex of cochlea to round window.

Scala vestibuli

Leads from oval window to apex of cochlea.


Auditory ossicle attached to oval window.

Tectorial membrane

Contacts hairs of hearing receptors.

Tympanic cavity

Air-filled space containing auditory ossicles.

Tympanic membrane (eardrum)

Cone-shaped, semitransparent membrane attached to malleus.

Utricle & saccule

2 expanded chambers where the organs of static equilibrium are located.

Temporal bone

The bone where all the balance organs are located in the skull.


The structure in the wall of the membranous labyrinth where the receptor cells of the balance organs are found.

Calcium carbonate

Otoliths are small grains composed of this.

Vestibular nerve

The nerve where sensory impulses travel from the organs of equilibrium to the brain.


The swelling canal the sensory organ of a semicircular canal lies within

Crista ampullaris

The sensory organ within the ampulla of a semicircular canal.


This part of the sensory organ that consists of a dome-shaped gelatinous mass.

Inertia of the fluid

Why when the head is moved, the fluid inside the membranous portion of a semicircular canal tends to remain stationary.


This part of the brain interprets impulses from the equilibrium receptors.

Aqueous humor

Fills anterior & posterior chambers of the anterior cavity of the eye.

Choroid coat

Posterior five-sixths of middle (vascular) tunic.

Ciliary muscles

Cause lens to change shape.


Inner lining of eyelid.


Transparent anterior portion of outer tunic.


Smooth muscle that controls light entering the eye.

Lacrimal gland

Secretes tears.

Optic disc

Area where optic nerve exits the eye.


Contains visual receptors called rods & cones.


White part of outer (fibrous) tunic.

Suspensory ligament

Connects lens to ciliary body.

Vitreous humor

Fills posterior cavity of eye.

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