LAB 8 SPECIAL SENSES

Lateral rectus muscle

Moves eye laterally

Medial rectus muscle

Moves eye medially

Moves eye medially

superior rectus muscle

elevates eye and turns it medially

inferior rectus muscle

depresses eye and turns it medially

Inferior oblique muscle

elevates eye and turns it laterally

superior oblique muscle

depresses eye and turns it laterally

cornea

Transparent, allows light to enter. (Most outerlayer of the eye)

iris

Colored part of the eye; controls size of the pupil and shows eye color

pupil

The black, center part of the eye; controls the amount of light entering the eye.

lens

RIght behind the iris and pupil; focuses light onto the retina.

ciliary body

Adjust shape of lens

suspensory ligament

Holds lens in place.

aqueous humor

Watery liquid that nourishes lens; its between the cornea and lens

vitreous humor

Gel-like substance that fills the space between the lens and retina, maintaining the eye's shape. It also helps to keep the retina in place.

Retina

contains neurons that respond to light. (Sensory layer)

choroid

contains blood vessels that supply oxygen and nutrients to the retina. (Vascular layer)

sclera

the white outer layer of the eyeball that maintains its shape and protects the inner components. (Fibrous layer)

optic nerve

bundle of neurons that carry visual signals

optic disc

The blind spot where retina lacks photoreceptors

if the shape of the eye is abnormal, producing blurred vision, what condition is present?

astigmatism.

Auricle (Pinna)

The outer part of the ear that collects sound waves and directs them into the ear canal.

External acoustic meatus (External auditory canal)

The passage leading from the outer ear to the eardrum, allowing sound waves to travel to the inner ear.

Tympanic membrane (Eardrum)

A thin membrane that separates the outer ear from the middle ear and vibrates in response to sound waves. (Middle ear)

Auditory ossicles

The three small bones (Maleus, incus, and stapes) located in the middle ear that amplify sound vibrations from the tympanic membrane to the inner ear.

Pharyngotympanic tube (Eustachian tube)

helping to equalize pressure in the ear. (Inner ear)

Vestibular nerve

Relays info. about motion and position. (Inner ear)

Cochlear nerve

relays info. on auditory signals (Inner ear)

Cochlea

A spiral-shaped organ in the inner ear responsible for converting sound vibrations into neural signals for hearing.

semicircular canals

Sense equilibrium (Inner ear) by detecting rotational movements of the head and maintaining balance.

Vestibule

sense equilibrium (Inner ear) and linear movement.

understand and interpret the weber test. distuinguish between conduction and sensorineural deafness

Weber Test:

• A vibrating tuning fork is placed on the middle of the forehead.

• Normal: Sound is heard equally in both ears.

• Conduction deafness: Sound is louder in the affected ear.

• Sensorineural deafness: Sound is louder in the unaffected (good) ear.

understand and interpret the rinne hearing tests. distuinguish between conduction and sensorineural deafness

Rinne Test:

• A vibrating tuning fork is placed on the mastoid bone (behind the ear) until the sound fades, then moved next to the ear canal.

• Normal: Air conduction (hearing next to the ear) is better than bone conduction (hearing on the bone).

• Conduction deafness: Bone conduction is better than air conduction.

• Sensorineural deafness: Both air and bone conduction are reduced, but air conduction is still better than bone.

distuinguish between conduction and sensorineural deafness

Conduction Deafness:

• Caused by a problem conducting sound waves (e.g., earwax blockage, ear infection, damage to ossicles).

Sensorineural Deafness:

• Caused by damage to inner ear structures or auditory nerve (e.g., aging, loud noise exposure, nerve damage).