Eye Anatomy and Taste Buds Overview

Study Notes

Eyebrows are coarse hairs over the supraorbital margins, shading the eyes and preventing perspiration from reaching them.
Orbicularis muscle depresses the eyebrows, while corrugator muscles move them medially.
Palpebrae (eyelids) protect the eye anteriorly.
Palpebral fissure separates the eyelids.
Canthi are the medial and lateral angles (commissures) of the eyelids.
Lacrimal caruncle contains glands that secrete a whitish, oily secretion (Sandman’s eye sand).
Tarsal plates of connective tissue support the eyelids internally.
Levator palpebrae superioris gives the upper eyelid mobility.
Eyelashes project from the free margin of each eyelid, initiating reflex blinking.
Lubricating glands associated with the eyelids include Meibomian glands, sebaceous glands, and ciliary glands between hair follicles.

Approximately 10,000 taste buds are primarily found on the tongue.
Papillae are found in the tongue mucosa and come in three types: filiform, fungiform, and circumvallate.
Fungiform and circumvallate papillae contain taste buds.

Five basic taste sensations exist:
- Sweet (sugars, saccharin, alcohol, some amino acids)
- Salt (metal ions)
- Sour (hydrogen ions)
- Bitter (alkaloids like quinine and nicotine)
- Umami (elicited by the amino acid glutamate)

Olfactory epithelium covers the superior nasal concha and is the organ of smell.
Olfactory receptor cells are bipolar neurons with radiating olfactory cilia.
Supporting cells surround and cushion the olfactory receptors.
Basal cells lie at the base of the epithelium.

This transparent membrane lines the eyelids (palpebral conjunctiva) and covers the whites of the eyes (ocular conjunctiva).
It lubricates and protects the eye.

Consists of the lacrimal gland and associated ducts.
The lacrimal gland secretes tears that contain mucus, antibodies, and lysozyme.
Tears enter the eye via superolateral excretory ducts and exit medially through the lacrimal punctum.