Flashcards in The Eye Deck (68)
The orbit is formed by which bones?
Frontal, maxillary, zygomatic bones and lacrimal
The orbit's boundaries - roof
frontal anf sphenoid
The orbit's boundaries - medial border
maxilla, lacrimal and ethmoid
The orbit's boundaries - lateral border
zygomatic and sphenoid
The orbit's boundaries - floor
maxilla and palatine
Why is the orbit concave?
to increase field of vision
Lateral margin of the orbit is at the junction of the...
frontal and zygomatic bones
The infraorbital margin extends upward to form what?
the anterior lacrimal crest
The supraorbital margin extends downward to form what?
the posterior lacrimal crest.
What is the purpose of the lacrimal apparatus?
to produce and drain lacrimal fluid (tears)
What do tears contain?
salt, mucous and lyzosymes
What is the function of the lacrimal gland?
Lubricates, moistens and cleans the conjunctiva
What does the lacrimal gland contain?
water, salt, mucin, and a bacterocidal enzyme
Explain what happens to the tears in the general process of removing them
half of them from the lacrimal gland evaporate. The remainder enter the papilla for drainage into the lacrimal sac. The lacrimal sac is connected to the nasolacrmal duct. Then it enters the nasal cavity and is covered by a mucous membrane.
What are the functions of the eyelashes/eyebrows?
Protects eyevall from foreign things, protects from perspiration, shades the eye from direct sun rays.
Which glands are at the base of the eyelids? What do they do?
Sebaceous (ciliary) glands are at the base, used to release a lubricating fluid into the hair follicles to avoid infection (like sty)
What do the sebaceous glands located between the eyelid and conjunctiva serve to do?
prevent sticking of eye
Which other glands are there of the eye?
suderiferous (sweat) glands
What does the lacrimal caruncle secrete?
sebacious and suderiferous glands
Which cranial nerve is associated with orbicularis occuli?
What does the levator palpebrae superioris (CIII) do?
raises upper lid
What are the 3 layers of the eyeball?
Fibrous, vascular and nervous tunic
What is the purpose of the sclera?
gives shape to and protects inner structure of eyeball.
What is the purpose of the cornea?
helps focus light through to the retina
Cornea has a (greater/lesser) convex curvature than the sclera.
Why is the choroid darkly pigmented?
For light absorption
What does the choroid do?
Provides nutrients to the retina
The ciliary body is layers of __________ muscle.
What does the ciliary body do?
Alters the shape of the lens (refraction or accommodation)