Eye Anatomy

Question 1

Eyebrows

Answer 1

short hairs located on the supraorbital margins; shade and prevent sweat from entering the eyes

Question 2

Eyelids

Answer 2

aka palpebrae; skin covered upper and lower lids, with eyelashes projecting from their free margin; protect the eyes and spread lacrimal fluid (tears) with blinking

Question 3

Tarsal Glands

Answer 3

modified sebaceous glands embedded in the tarsal plate of the eyelid; secrete an oily secretion that lubricates the surface of the eye

Question 4

Ciliary Glands

Answer 4

typical sebaceous and modified sweat glands that lie between eyelash follicles; secrete an oily secretion that lubricates the surface of the eye and the eyelashes; an infection of the ciliary gland is a sty

Question 5

Conjunctivae

Answer 5

a clear mucous membrane that lines the eyelids (palpebral conjunctivae) and lines the anterior white of the eye (bulbar conjunctiva); secrete mucus to lubricate the eye; inflammation of the conjunctiva results in conjunctivites

Question 6

Medial and Lateral Commissures

Answer 6

junctions where the eyelids meet medially and laterally; form the corners of the eyes; the medial commissure contains the lacrimal caruncle

Question 7

Lacrimal Caruncle

Answer 7

fleshy reddish elevation that contains sebaceous and sweat glands; secretes a whitish oily secretion for lubrication of the eye (can dry and form “eye sand”)

Question 8

Larimal Apparatus

Answer 8

includes the lacrimal gland and a series of ducts that drain the lacrimal fluid in the nasal cavity; protects the eye by keeping it moist; blinking spreads lacrimal fluid

Question 9

Lacrimal Gland

Answer 9

located in the superior ad lateral aspect of the orbit of the eye; secretes lacrimal fluid, which contains mucus, antibodies and lysozyme

Question 10

Lacrimal Puncta

Answer 10

two tiny openings on the medial margin of each eyelid; allow lacrimal fluid to drain into the superior and inferiorly located lacrimal canaliculi

Question 11

Lacrimal Canaliculi

Answer 11

two tiny canals that are located in the eyelids; allow lacrimal fluid to drain into the lacrimal sac

Question 12

Lacrimal Sac

Answer 12

a single pouch located in the medial orbital wall; allows lacrimal fluid to drain into the nasolacrimal duct

Question 13

Nasolacrimal Duct

Answer 13

a single tube that empties into the nasal cavity; allows lacrimal fluid to flow into the nasal cavity

Question 14

Extrinsic Eye Muscles

Answer 14

six muscles for each eye; four recti and two oblique muscles; controls the movement of each eyeball and hold the eyes in the orbits

Question 15

What makes up the fibrous layer?

Answer 15

it is the external layer; sclera and cornea

Question 16

What makes up the vascular layer?

Answer 16

middle layer; choroid, ciliary body, ciliary muscle, ciliary process, ciliary zonule (suspensory ligament), iris, and pupil

Question 17

What makes up the inner layer?

Answer 17

retina; pigmented layer of the retina, neural layer of the retina

Question 18

Sclera

Answer 18

opaque white connective tissue that forms the “white of the eye”; helps to maintain the shape of the eyeball and provides an attachment point for extrinsic eye muscles

Question 19

Cornea

Answer 19

structurally continous with the sclera; modified to form a transparent layer that bulges anteriorly; contains no blood vessels; forms a clear window that is the major light bending (refracting) medium of the eye

Question 20

Choroid

Answer 20

a blood-vessel rich, dark membrane; the blood bessels nourish the other layers of the eye and the melanin helps to absorb excess light

Question 21

Ciliary Body

Answer 21

modification of the choroid that encircles the lends; contains the ciliary muscle and the ciliary process

Question 22

Ciliary Muscle

Answer 22

smooth muscle found within the ciliary body ; alters the shape of the lends with contraction and relaxationC

Question 23

Ciliary Process

Answer 23

radiating folds of the ciliary muscle; capillaries of the ciliary process form the aqueous humor by filtering plasma

Question 24

Ciliary Zonule

Answer 24

suspensory ligament; a halo of fine fibers that extends from the ciliary process around the lend; attaches the lens to the ciliary process

Question 25

Iris

Answer 25

the anterior portion of the vascular layer that is pigmented; it contains two layers of smooth muscle (sphicnter pupillar and dilator pupillae); controls the amount of light entering the eye by chanign the size of the pupil diameter; the sphincter pupillae contract to constrict the pupil; the dilartor pupillae contract to dialte the pupil

Question 26

Pupil

Answer 26

the round central opening of the iris; allows light to enter the eye

Question 27

Pigmented Layer of the Retina

Answer 27

the outer layer that is composed of only a single layer of pigment cells (melanocytes); absorbs light and prevents it from scattering in the eye; pigment cells act as phagocytes for cleaning up cell debris and also store vitamin A needed for photoreceptor renewal

Question 28

Neural Layer of the Retina

Answer 28

the thicker inner layer composed of the three main types of neurons: photoreceptors (rods and cones), bipolar cells, and ganglion cells; photoreceptors respond to light and convert the light energy into action potentials that travel to the primary visual cortex of the brain