Exam 1 : Eye and Ear anatomy

Fibrous Tunic

Fibrous Tunic

Outer layer of the eye providing structural support

Vascular Tunic

Middle layer of the eye with blood vessels

Nervous Tunic

Inner layer of the eye containing the retina and optic nerve

Lens Accommodation

Ability of the lens to adjust focus for different distances

Iris Organization

Arrangement of muscles in the iris controlling pupil size

Visual Systems Connections

Major neural pathways and connections for vision

External Auditory Meatus

Ear canal leading to the eardrum

Ear Ossicles

Small bones in the middle ear transmitting sound vibrations

Neuron Components

Nerve cells associated with sensory perception

Lymphatic Components

Vessels and nodes involved in immune response

Pain Receptors

Nociceptors sensing tissue damage

Chemoreceptors

Receptors sensitive to chemical changes in the environment

Thermoreceptors

Receptors detecting temperature variations

Mechanoreceptors

Receptors responsive to mechanical stimuli like touch and pressure

Photoreceptors

Rods and cones in the eye sensitive to light

Free Nerve Endings

Nerve endings sensing pain in skin and tissues

Referred Pain

Pain perceived in a different location than the stimulus site

Acute Pain Fibers

Myelinated nerve fibers transmitting sharp pain signals

Chronic Pain Fibers

Unmyelinated fibers conveying dull, persistent pain

Orbital Cavity

Space in the skull housing the eye and its accessory organs

Palpebrae

Eyelids responsible for protecting and lubricating the eye

Lacrimal Apparatus

Structures producing and draining tears for eye lubrication

Orbicularis Oculi Muscle

Muscle closing the eye, innervated by the facial nerve

Levator Palpebrae Superioris Muscle

Muscle elevating the upper eyelid, innervated by the oculomotor nerve

Rectus Muscles

Muscles moving the eyeball in different directions, innervated by specific cranial nerves

Oculomotor n. (CN III)

Innervates superior, inferior, and medial rectus muscles.

Abducens (abducent) n. (CN VI)

Innervates lateral rectus muscle.

Trochlear n. (CN IV)

Innervates superior oblique muscle.

Superior rectus m.

Innervated by Oculomotor n. (CN III).

Inferior rectus m.

Innervated by Oculomotor n. (CN III).

Medial rectus m.

Innervated by Oculomotor n. (CN III).

Lateral rectus m.

Innervated by Abducens (abducent) n. (CN VI).

Superior oblique m.

Innervated by Trochlear n. (CN IV).

Inferior oblique m.

Innervated by Oculomotor n. (CN III).

Levator palpebrae superioris m.

Elevates upper eyelid, innervated by Oculomotor n. (CN III).

Sclera

Fibrous outer layer of the eye.

Cornea

Transparent, avascular outer layer covering the iris and pupil.

Iris

Colored portion dividing anterior cavity into chambers.

Ciliary body

Secretes aqueous humor, holds lens in place.

Retina

Inner layer containing photoreceptors for vision.

Optic Nerve (CN II)

Transmits visual information to the brain.

Canal of Schlemm

Drains aqueous fluid from the eye.

Glaucoma

Increased intraocular pressure damaging the optic nerve.

Aqueous humor

Fluid nourishing the eye and maintaining intraocular pressure.

Vitreous humor

Gel-like substance filling the posterior cavity of the eye.

Sphincter pupillae m.

Constricts the pupil under parasympathetic control.

Dilator pupillae m.

Dilates the pupil under sympathetic control.

Mydriasis

Pupil dilation caused by radial muscle contraction

Optic Disc

Point where nerve fibers exit the retina

Fovea Centralis

Central depression in the retina for sharpest vision

Vitreous Humor

Clear, jelly-like fluid in the posterior eye cavity

Macula Lutea

Part of the retina with the fovea centralis

Optic Cup

Structure where nerve fibers join the optic nerve

Rods

Retinal cells sensitive to light for dark vision

Cones

Retinal cells for color vision in bright light

Ganglion Cell

Tertiary neuron in the retina for signal transmission

Bipolar Cells

Secondary neuron in the retina for signal processing

Eustachian Tube

Connects middle ear to nasopharynx, equalizes pressure

Semicircular Canals

Aid in equilibrium, located in inner ear

Cochlea

Functions in hearing, contains hair cells

Organ of Corti

Lined with hair cells, converts vibration to nerve impulses

Vestibule

Part of inner ear, contains utricle and saccule

Scala Vestibuli

Part of cochlear duct, contains endolymph

Scala Media

Part of cochlear duct, contains organ of Corti

Scala Tympani

Part of cochlear duct, contains perilymph

Oval Window

Connects middle ear to cochlea

Round Window

Allows for fluid movement in cochlea

Ampulla

Elevation in semicircular ducts, contains hair cells

Cupula

Covering hair cells in ampullae, senses rotational acceleration

Otoliths

Located in saccule and utricle, sensitive to gravity

Static Equilibrium

Senses head position while still, located in vestibule

Dynamic Equilibrium

Detects motion aiding in balance, located in semicircular canals

Crista Ampullaris

Sensory organ in semicircular canals, contains hair cells

Vestibulocochlear Nerve

Cranial nerve CN VIII, involved in hearing and equilibrium

Acoustic Meatus

Ear canal where sound waves enter

Thalamus

Relay station for sensory impulses to auditory cortex

Temporal Lobe

Location of primary auditory cortex in the brain

Cochlear Nerve

Transmits auditory information to the brain

Cochlear Duct

Contains scala vestibuli, scala media, & scala tympani