Review of Senses: General and Special

Vocabulary flashcards for key terms related to general and special senses, with a focus on the ear and eye anatomy and function.

General Senses

Receptors throughout the body; can be somatic or visceral. Examples include tactile, thermal, pain, and proprioception.

Tactile Senses

Touch, itch, and pressure sensations.

Thermal Senses

Hot and cold sensations.

Proprioception

The sense of knowing where our body and body parts are.

Special Senses

Receptors located in one specific place; examples include gustatory, olfactory, vision, hearing, and equilibrium.

Gustatory Sense

Taste sensation.

Olfactory Sense

Smell sensation.

Cribriform plate

Olfactory nerves travel through this to the superior nasal cavity.

Taste (Gustation)

Receptors located in papillae on the tongue.

Auricle (Pinna)

Gathers sound waves and funnels them into the external auditory meatus; mostly elastic cartilage covered with skin.

External Auditory Meatus (EAM)

Short tube running from auricle to tympanic membrane, lined with hairs, sebaceous glands, and ceruminous glands.

Tympanic Membrane

Also called the eardrum; the boundary between the external and middle ear that vibrates when sound waves enter.

Middle Ear

Air-filled space medial to tympanic membrane, located inside petrous portion of temporal bone.

Round window and Oval window

Holes in bony wall between middle and inner ear.

Auditory Ossicles

Three ear bones that transmit vibrations from tympanic membrane to inner ear: malleus, incus, and stapes.

Middle Ear Muscles

Two muscles that dampen loud sounds by reducing the movement of the ossicles: tensor tympani and stapedius.

Pharyngotympanic Tube (Auditory or Eustachian Tube)

Connects middle ear to nasopharynx, allowing equalization of pressure on both sides of tympanic membrane.

Otitis Media

Middle ear infection from nasopharynx via pharyngotympanic tube; fluid builds up in middle ear.

Bony Labyrinth

Cavity made of semicircular canals, vestibule, and cochlea.

Membranous Labyrinth

Walls and sacs inside the bony labyrinth.

Cochlea

Part of the inner ear responsible for hearing.

Vestibule

Part of the inner ear responsible for equilibrium (acceleration).

Semicircular Canals

Part of the inner ear responsible for equilibrium (rotation).

Spiral Organ

Receptor organ for hearing, has stereocilia (hair cells), inside the cochlear duct.

Conductive Hearing Loss

Results from issues with external and middle ear, sounds like volume was turned down.

Sensorineural Hearing Loss

Results from issues with inner ear, CN VIII, and possibly brain; sounds like things aren’t tuned correctly.

Vestibule

Detects linear acceleration; contains utricle and saccule.

Semicircular Canals

Detect rotation to help with equilibrium; three semicircular canals at right angles to each other.

External Structures

Eyelids protect eyeball from excessive light and injury; inside covered in conjunctiva.

Conjunctiva

Mucus membrane covering inner eyelids and sclera; keeps cornea moist.

Lacrimal Glands

Located in supero-lateral corner of orbit; supplies eyes with lacrimal fluid (tears).

Fibrous Layer

Most external layer of eye, tough outer covering; includes sclera and cornea.

Sclera

Tough outer covering of the eye (white of the eye); protects eyeball.

Cornea

Continuation of sclera, transparent, allows light into eye, acts as fixed lens for focusing.

Vascular Layer

Middle layer or tunic of eyeball; includes choroid, ciliary body/muscles, and iris.

Choroid

Heavily pigmented vascular layer; melanin helps absorb light.

Ciliary Body/Muscles

Surrounds the lens and controls lens shape for precise focusing (adapting for near/far vision).

Iris

Colored part of the eye, regulates light entering eye; controls pupil diameter.

Retinal Layer

Deepest tunic or layer of the eyeball; includes retina and optic nerve.

Retina

Converts light to nerve impulses.

Optic Nerve (CN II)

Transmits nerve impulses to brain.

Pigmented Layer

Has melanocytes; absorbs light and keep it from scattering.

Neural layer

Nervous tissue with photoreceptive cells (rods and cones).

Rods

Work best in dim light

Cones

Used for bright light and color vision (Perceive red, blue, green).

Macula Lutea

Area of concentrated cone cells at posterior pole

Fovea centralis

Area of only cone cells in center of macula lutea. Region with highest visual acuity

Optic Disc

Blind spot, location where optic nerve attaches. No photoreceptor cells

Lens

Avascular, transparent disk, its shape can be changed to adjust focus (deformable).

Lens

Adjusts to allow focusing of near items, which is called accommodation (lens becomes more spherical). Ciliary muscle contracts and allows lens to change shape.