Anatomy and Physiology 2 Chapter 17 - External Eye Anatomy

what do the accessory structures of the eye do?

provide protection, lubrication, and support to the eyeball

what are the 5 accessory structures of the eye

1. palpebrae

2. eyelashes (includes tarsal glands)

3. lacrimal caruncle

4. conjunctiva (includes palpebral and bulbar/ocular)

5. lacrimal apparatus (lacrimal gland, lake/caruncle, puncta, canaliculi, and sac)

palpebrae (eyelids)

keeps eye lubricated and removes dust and debris

includes the following parts of the eyelids: upper and lower eyelid, palpebral fissure (space between the eyelids), and the medial and lateral canthus (connection points of the eyelids)

eyelashes

strong hairs to keep foreign matter from the eye; includes the tarsal (meibomian) glands

tarsal (meibomain) glands

secrete sebaceous fluid; lipid-rich secretions prevent us from losing water to the outside world and keeps eyelids from sticking together

lacrimal caruncle

soft tissue producing grit

conjunctiva

epithelium covering inner eyelid and outer eyeball surface; includes the palpebral and bulbar/ocular

palpebral

part of the conjunctiva and is the inner lids

bulbar/ocular

part of the conjunctiva and is the anterior surface

lacrimal apparatus

produce, distributes, and removes tears (keeps eye hydrated, moves O2 and minerals, and removes dust/debris); includes the lacrimal gland, lake/caruncle, puncta, canaliculi, and sac

lacrimal gland (tear gland)

makes tears; contains antibacterial lysozyme and antibodies and is mixed with tarsal gland products

lacrimal lake/caruncle

collects and drains tears

lacrimal puncta

pores on top and bottom of lids that drain lake into the lacrimal canaliculi

lacrimal canaliculi

small canals that lead to the lacrimal sac

lacrimal sac

drains into the nasolacrimal duct

nasolacrimal duct

connects the eye’s tear drainage to the nasal cavity