Lab Exam 4
Posterior horns
Resemble the upper wings of a butterfly (in a spinal cord cross section).
Crista ampullaris
The sensory organ within the ampulla of a semicircular canal.
Cerebral Cortex
Thin layer of gray matter on surface of cerebrum.
Cerebellum
This part of the brain interprets impulses from the equilibrium receptors.
Cupula
This part of the sensory organ that consists of a dome-shaped gelatinous mass.
Interneuron
Transmits impulse from sensory to motor neuron withing central nervous system.
Sensory (afferent) neuron
Transmits impulse into brain or spinal cord from receptors.
Motor (efferent) neuron
Transmits impulse out of the brain or spinal cord to effectors (muscles and glands).
Cornea
Transparent anterior portion of outer tunic.
Sarcomere
Unit of alternating light and dark striations between Z lines.
Ceruminous gland
Wax-secreting structure.
Central canal
Found in the gray commissure of the spinal cord & contains cerebrospinal fluid & is continuous with the ventricles of the brain.
Posterior median sulcus
A groove that extends the length of the spinal cord posteriorly.
Tympanic cavity
Air-filled space containing auditory ossicles.
Sarcoplasm
Cytoplasm of a muscle fiber.
Retina
Contains visual receptors called rods & cones.
Conjunctiva
Inner lining of eyelid.
Oligodendrocyte
Myelin-forming neuroglia in brain & spinal cord.
Calcium carbonate
Otoliths are small grains composed of this.
Midbrain
Part of brainstem between diencephalon and pons.
Medulla oblongata
Part of brainstem continuous with the spinal cord.
Hypothalamus
Part of diencephalon that forms lower walls and floor of third ventricle.
Sarcolemma
Cell membrane of a muscle fiber.
Ependymal Cell
Cells that cover the inside spaces of the brain ventricles and help regulate cerebrospinal fluid.
Sarcoplasmic reticulum
Cellular organelle in muscle fiber corresponding to the endoplasmic reticulum.
Pineal gland
Cone-shaped structure attached to upper posterior portion of diencephalon.
Tympanic membrane (eardrum)
Cone-shaped, semitransparent membrane attached to malleus.
Fascia
Connective tissue located between adjacent muscles.
Corpus callosum
Connects cerebral hemispheres.
Suspensory ligament
Connects lens to ciliary body.
Auditory tube
Connects middle ear & pharynx.
Gray commissure
Connects the gray matter on the left and right sides of the spinal cord.
Tectorial membrane
Contacts hairs of hearing receptors.
Membranous labyrinth
Contains endolymph.
Tendon
Cordlike part that attaches a muscle to a bone.
Chromatophilic substance (Nissl bodies)
Corresponds to rough endoplasmic reticulum in other cells.
Vitreous humor
Fills posterior cavity of eye.
Choroid coat
Posterior five-sixths of middle (vascular) tunic.
Gyrus (convolution)
Ridge on surface of cerebrum.
Pons
Rounded bulge on underside of brainstem.
External acoustic meatus
S-shaped tube leading to tympanic membrane.
Lacrimal gland
Secretes tears.
Central sulcus
Separates frontal & parietal lobes.
Effector
Structure capable of responding to motor impulse.
Optic chiasma
Structure formed by the crossing-over of the optic nerves.
Myelin Sheath
Substance of Schwann cell composed of lipoprotein that insulates axons and increases impulse speed.
Falx cerebelli
A layer of dura mater that separates cerebellar hemispheres.
Collateral
Branch of an axon.
Scala tympani
Extends from apex of cochlea to round window.
Microglia
Phagocytic neuroglia.
Myosin
Protein found within thick filament.
Iris
Smooth muscle that controls light entering the eye.
Ganglion
Specialized mass of neuron cell bodies outside the brain or spinal cord.
Utricle & saccule
2 expanded chambers where the organs of static equilibrium are located.
Fascicle
A small bundle of muscle fibers.
Malleus
Auditory ossicle attached to tympanic membrane.
Optic disc
Area where optic nerve exits the eye.
Stapes
Auditory ossicle attached to oval window.
Osseous (bony) labyrinth
Bony canal of inner ear in temporal bone.
Ciliary muscles
Cause lens to change shape.
Insula
Cerebral lobe located deep within lateral sulcus.
Aqueous humor
Fills anterior & posterior chambers of the anterior cavity of the eye.
Perimysium
Layer of connective tissue that separates a muscle into small bundles called fascicles.
Epimysium
Layer of connective tissue that surrounds a skeletal muscle.
Endomysium
Layer of connective tissue that surrounds an individual muscle fiber.
Scala vestibuli
Leads from oval window to apex of cochlea.
Transverse (T) tubule
Membranous channel extending inward from muscle fiber membrane.
Axon
Nerve fiber arising from a slight elevation of the cell body that conducts an impulse away from the cell body.
Neurofibrils
Netowrk of fine threads extending into nerve fiber.
Dendrite
Neuron process with many branches that conducts an impulse toward the cell body.
31 pairs
Number of spinal nerves in the spinal cord.
Neurilemma
Sheath of Schwann cell containing cytoplasm and nucleus that encloses myelin.
Astrocyte
Star-shaped neuroglia between neurons and blood vessels.
Temporal bone
The bone where all the balance organs are located in the skull.
Lumbar enlargement
The bulge in the spinal cord that gives off nerves to the lower limbs.
Cervical enlargement
The bulge in the spinal cord that gives off nerves to the upper limbs.
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.
Vestibular nerve
The nerve where sensory impulses travel from the organs of equilibrium to the brain.
Macula
The structure in the wall of the membranous labyrinth where the receptor cells of the balance organs are found.
Ampulla
The swelling canal the sensory organ of a semicircular canal lies within
Anterior horns
Where the cell bodies of motor neurons are found in the spinal cord.
Sclera
White part of outer (fibrous) tunic.
Inertia of the fluid
Why when the head is moved, the fluid inside the membranous portion of a semicircular canal tends to remain stationary.
