Special Senses: Vision, Olfaction, and Gustation

Flashcards for vision, olfaction, and gustation based on lecture notes.

Olfaction

The sense of smell.

Gustation

The sense of taste.

Accessory Structures (of the eye)

Provide support, protection, and lubrication for the eye; including eyelids.

Palpebrae

Upper & lower eyelids; lubricate, protect, and sweep debris off the eye.

Tarsal Glands

Specialized sebaceous glands located along the inner edge of the palpebrae.

Tarsal Glands Function

Secrete a fatty substance that prevents palpebrae from sticking together.

Lacrimal Caruncle

A gland of the medial canthus that produces thick deposits that trap and collect debris.

Palpebral Conjunctiva

Epithelium covering the inner surface of the palpebrae.

Ocular Conjunctiva

Epithelium covering the outer surface of the eye.

Conjunctivitis (Pinkeye)

Inflammation of either conjunctiva, caused by simple irritation or infection.

Cornea

Transparent epithelium covering the center surface of the eye.

Lacrimal Apparatus

Produce, distribute, and remove tears.

Tear Function

Tears protect the conjunctival surfaces by keeping them moist, reducing friction, removing debris, preventing them from sticking together, supplying oxygen and nutrients, and killing bacteria (lysozyme).

Lacrimal Gland (Tear Gland)

Superior & lateral to the eye ball; produces tears that flow over conjunctival surfaces.

Lacrimal Puncta

Two small pores that drain tears into the lacrimal sac.

The Eye

Located in the orbit; surrounded and cushioned by orbital fat.

Fibrous Tunic

Outer layer of fibrous connective tissue; contains the sclera.

Sclera

White of the eye; attachment site for rectus muscles that move the eyeball.

Cornea

Allows light to enter the eye; transparent epithelium on the anterior center surface of the eye.

Vascular Tunic

Middle layer of the eye wall; deep to the cornea and superficial to the lens; contains the iris.

Iris

Pigmented portion of the eye; contains the pupillary muscles.

Ciliary Muscle

Located around the lens; maintains the proper position of the lens.

Ciliary Muscle Function

Accommodates (adjusts) the shape of the lens to focus images onto the retina at the back of the eye.

Neural Tunic

Inner layer of the eye wall; contains the neural part and pigmented part.

Neural Part (of Retina)

Contains photoreceptors; inner most layer of the neural tunic.

Pigmented Part (of Retina)

Absorbs light; prevents light from reflecting back across the neural part.

Rods

Sensitive to light; allow us to see in dim light; located around the periphery of the retina.

Cones

Sensitive to color; provide color vision, but only when the light is bright.

Fovea

Area of sharpest vision; most cones are concentrated here.

Optic Disc

All 1 million sensory neurons converge here and form the optic nerve; also called the blind spot.

Posterior Cavity

Large space behind the lens and ciliary body; contains the vitreous body.

Vitreous Body

A gelatinous mass that maintains the shape of the eye.

Anterior Cavity

Between the cornea and iris; contains the anterior chamber and posterior chamber.

Aqueous Humor

CSF-like fluid that supplies nutrients and removes wastes; circulates between ant. & post. chambers.

The Lens

Located posterior to the iris; filled with crystallins; focuses images onto the photoreceptors (retina).

Crystallins

Proteins that allow for clarity and focus in the lens.

Cataract

Lens becomes cloudy and yellow; a condition resulting from the loss of transparency within the lens.

Accommodation

The ability of the lens to change shape to focus on objects; controlled by ciliary muscles.

Olfactory Organs

Located on each side of nasal septum; inferior side of cribriform plate and on the superior conchae of the ethmoid bone.

Olfactory Epithelium

A layer of epithelium that contains olfactory receptors, basal cells, olfactory glands, and olfactory cilia.

Olfactory Receptors

Specialized smell receptors.

Basal Cells

Olfactory receptor stem cells.

Olfactory Glands

Mucous secreting cells that enhance receptor sensitivity.

Olfactory Cilia

Contain receptor proteins.

Odorants

Water or fat soluble chemicals that come in contact with the mucous covered olfactory cilia of the olfactory receptors.

Taste Buds

Specialized sensory structures, located on the surface of the tongue, pharynx, & larynx; each contain about 40 taste receptors called gustatory cells.

Gustatory Cells

Taste receptors located in taste buds; long receptor cells with taste hairs that extend through taste pores and into the taste bud.

Primary Taste Sensations

Sweet, sour, salty, bitter.

Lingual Papillae

Epithelial projections on the surface of the tongue.

Filiform Papillae

Tall thread-like projections that do not contain taste buds; provide friction to help the tongue move substances around the mouth.

Fungiform Papillae

Mushroom-like projections that each contain about 5 taste buds.

Circumvallate Papillae

Each contain about 100 taste buds; located at back of tongue.