m07 test

What are the five special senses?

Vision, taste, smell, hearing, equilibrium.

Where are special sense receptors located?

In distinct, localized receptor cells in the head.

What percentage of sensory receptors are in the eye?

70%.

What protects the eye?

Cushion of fat and bony orbit.

What are the accessory structures of the eye?

Eyebrows, eyelids, conjunctiva, lacrimal apparatus, extrinsic muscles.

What is the function of eyebrows?

Shade the eyes; prevent sweat from reaching eyes.

What is the palpebral fissure?

Space between eyelids.

What is the lacrimal caruncle?

Gland at medial commissure with oil and sweat glands.

What muscle opens the upper eyelid?

Levator palpebrae superioris.

Which cranial nerve controls levator palpebrae superioris?

CN III (oculomotor).

Which glands lubricate eyelids?

Tarsal (oil) and ciliary (sweat) glands.

What are the two types of conjunctiva?

Palpebral (eyelids) and bulbar (covers sclera).

What is conjunctivitis?

Inflammation of conjunctiva.

What produces tears?

Lacrimal gland.

What is the tear drainage pathway?

Puncta → canaliculi → lacrimal sac → nasolacrimal duct.

Which muscle moves the eye laterally?

Lateral rectus (CN VI).

Which muscle moves the eye via the trochlea?

Superior oblique (CN IV).

What are the three layers of the eyeball?

Fibrous, vascular, inner (retina).

What are the two regions of the fibrous layer?

Sclera and cornea.

What are the functions of the sclera?

Protects, shapes eye, anchors muscles.

What is the function of the cornea?

Bends light; has pain receptors.

What are the three parts of the vascular layer (uvea)?

Choroid, ciliary body, iris.

What is the function of the choroid?

Provides blood supply and absorbs light.

What controls lens shape?

Ciliary muscles.

What controls pupil size?

Iris (circular constrict, radial dilate).

What are the two layers of the retina?

Pigmented and neural layers.

What photoreceptors are for dim light?

Rods.

What photoreceptors are for bright light and color?

Cones.

What is the macula lutea?

High cone density area; center has fovea.

What divides anterior and posterior eye segments?

Lens and ciliary zonule.

What fluid is in the posterior segment?

Vitreous humor.

What fluid is in the anterior segment?

Aqueous humor.

Where is aqueous humor drained?

Scleral venous sinus (canal of Schlemm).

What is the cause of glaucoma?

Blocked aqueous drainage → ↑ pressure → optic nerve damage.

What is a cataract?

Clouding of the lens.

What refracts most light entering the eye?

Cornea.

What are the three processes for close vision?

Accommodation, constriction, convergence.

What is myopia?

Nearsightedness (eyeball too long).

What is hyperopia?

Farsightedness (eyeball too short).

What is the optic disc?

Blind spot where optic nerve exits.

What is the main visual pathway?

Optic nerve → chiasma → tract → LGN → optic radiation → occipital cortex.

Where are olfactory receptors located?

Olfactory epithelium in nasal cavity roof.

What type of neurons are olfactory neurons?

Bipolar neurons.

What nerve carries smell?

CN I (olfactory nerve).

Where do olfactory neurons synapse?

Mitral cells in olfactory bulb.

What brain system processes emotional smell responses?

Limbic system.

Where are most taste buds located?

Papillae of the tongue.

What are the five primary tastes?

Sweet, sour, salty, bitter, umami.

What is the taste nerve for the anterior 2/3 of the tongue?

Facial nerve (CN VII).

What is the taste nerve for the posterior 1/3 of the tongue?

Glossopharyngeal nerve (CN IX).

What is the final destination of taste signals?

Gustatory cortex (insula).

What structures make up the outer ear?

Auricle and external acoustic meatus.

What vibrates first in hearing?

Tympanic membrane.

What are the auditory ossicles?

Malleus, incus, stapes.

What is the function of the pharyngotympanic tube?

Equalizes pressure between middle ear and atmosphere.

What is otitis media?

Middle ear infection.

What are the three regions of the bony labyrinth?

Vestibule, semicircular canals, cochlea.

What fluid is in the bony labyrinth?

Perilymph.

What fluid is in the membranous labyrinth?

Endolymph.

What are the three chambers of the cochlea?

Scala vestibuli, scala media, scala tympani.

What is the receptor organ for hearing?

Organ of Corti.

What membrane moves with sound waves?

Basilar membrane.

What pushes on the oval window?

Stapes.

What determines pitch?

Location of vibrating basilar membrane fibers.

Where do low-frequency sounds vibrate?

Cochlear apex (helicotrema).

Where do high-frequency sounds vibrate?

Near the oval window (base).

What is the auditory pathway?

Cochlear nerve → cochlear nuclei → superior olivary nucleus → inferior colliculus → thalamus → auditory cortex.

What allows sound localization?

Differences in timing and intensity between ears.

What receptors detect static equilibrium?

Maculae in utricle and saccule.

What movement does the utricle detect?

Horizontal movement.

What movement does the saccule detect?

Vertical movement.

What detects rotational movement?

Crista ampullaris in semicircular canals.

What is conduction deafness?

Blocked sound conduction (e.g., wax, otitis media).

What is sensorineural deafness?

Damage to hair cells or neural auditory pathway.

What is tinnitus?

Ringing in the ears without stimulus.

What is Ménière's syndrome?

Disorder affecting cochlea & semicircular canals causing vertigo, nausea, hearing loss.