Anatomy And Physiology

Front 1

Crying

Back 1

Parasympathetic stimulation of lacrimal glands over-secreation of tears and tears spill over edge of eyelids.

Front 2

Optic disc. AKA blind spot

Back 2

Site where optic nerve exits the eyeball

Front 3

Six Extrinsic Eye Muscles

Back 3

1.) Lateral & medial rectus
2.) Superior & inferior rectus
3.) Superior & inferior obliques

Front 4

Sty

Back 4

infection of the ciliary gland

Front 5

Posterior segment

Back 5

Larger; between lens and retina and filled with jelly-like substance; vitreous body - formed during embryonic life and does not undergo replacement. Contributes to intraocular pressure and prevents eyeball from collaplsing and keeps retina smoothly pressed against choroid.

Front 6

Lacrimal fluid

Back 6

Just superior and lateral to eyeball; almond size/shape; secrets: lacrimal fluid - serous sol. of salts/mucous/lysozyme; lubricates/cleans/moistens eyeball

Front 7

Fovea centralis

Back 7

Small depression in center of macula lutea contians cones only that are not covered by bipolar and ganglion cells; area of highest visual acuity or resolution.

Front 8

Lacrimal apparatus

Back 8

Group of structures that produce/drain tears, AKA lacrimal fluid.

Front 9

Macula lutea

Back 9

Exact center of postior portion of retina

Front 10

Macular degeneration

Back 10

New blood vessels grow over macula lutea and distorted vision and blindness results.

Front 11

Anerior Segment

Back 11

Anterior to lens; further divided into: anterior chamber - behind cornea/in front of iris filled with serous fluid; aquous humor- formed from blood capillaries in ciliary process; undergoes contant replacement and helps noursih cornea and lens. Forms intraocular pressure, approx. 16 mm Hg, that, along with vitreous body; maintains eyeball shape; keeps retina smoothly pressed against choroid for an even surface for reception of clear images

Front 12

Wall of the Eyeball

Back 12

Fibrous tunic: superficial, avascular wall
Cornea: anterior; avascular; transparent membrane covering colored iris; is curved to help focus.refract (bend) light.
Sclera, AKA "white of the eye": dense CT covering all of th eyeball rigid, fiving it shape; protects inner parts

Front 13

Opthalmoscope

Back 13

medical instrument to look through pupil to see a magnified image of the posterior wall (fundus of the retina and its anterior blood vessels) (to view pathological changes, as wth HTN or DM)

Front 14

Vascular Tunic AKA Uvea

Back 14

Middle wall
a.) Choroid: posterior portion; highly vascular - provides nutrients to posterior retina
b.) Ciliary Body: anterior extension of choroid
c.) Ciliary process: internal folds that secrete serous aqueous humor
d.) ciliary muscle: band of smooth muscle that alters shape of lens

Front 15

Vascular Tunic - Iris

Back 15

Flat, donut-shaped, colored portion of eyeball; suspended between cornea & lens; attached at outer margin to ciliary process; regulates the amount of light entering eyeball through the pupil

Front 16

Lens

Back 16

Just posterior to the pupil and iris, avascular; transparent; consists of onion-layered proteins.
Function: focus/refract light rays for clear vision.

Front 17

Vascular Tunic - Pupil

Back 17

Opening/hole in center of iris. Bright light of parasympathetic stimulation, pupil constriction dim light of sympathetic stimulation, pupil dilation

Front 18

Conjunctiva

Back 18

Thin, proctective mucous membrane; lines from inner aspect of eyelids onto anterior eyeball
a.) palpebral - lines the inner eyelid
b.) bulbar/ocular- lines the outer eyeball
c.) bloodshot eyes - dilated blood vess. of conjunctiva on eyeball.
d.) conjunctivitis, AKA pinkeye - inflammation of conjunctive usually caused by bacteria; sometimes caused by an irritant (dust, smoke, pollution)

Front 19

Accommodation of the lens

Back 19

Increase in convex curvature of the lens (ant. and post. surface) for near vision.
Presbyopia - with aging, lens loses elasticity and its ability to accommodate.

Front 20

Physiology of Vision

Back 20

Visual transduction of light into an electrical signal.
1. Absorption of light by photopigments in rods and cone (photoreceptor).
a.) Photpigment = colored proteins in rods/cones that undergo structural changes when they absorb light.
i.) Rhodopsin - the single photopigment in rods.
ii.) Three different photopigment for three different types of cones (color blindness: due to absence of the cone photopigment sensitive to red or green light).
b.) All photopigment contain:
i.) Opsin - a glycoprotein; 4 diffe. types - 1 for each photopigment and each type (due to variations of a.a. sequences) abosrbs different wavelengths of incoming light.
ii.) retinal a vitamin A derivative; the light- absorbing portion (night blindness - inability to see will at low light levels; caused by a long- term deficiency of vitamin A and decreases amounts of retinal.
c.) When light is absorbed, retinal changes shape (isomerization) and seperates for opsin (AKA bleaching); (in darkness, it is converted back to its
original shape).
d.) decreased release of an inhibitory neurotransmitter, blutamic acid, thereby exciting the bipolar cells that synapse with rods. Bipolar cells that synapse with cones may be excited or inhibited by light.
e.) Excited bipolar cells synapse with, and, excite ganglion cells, which become depolarized and initiate nerve impulses
f.) ganglion cells leave retina as optic (II) nerve fibers, optic chiasm, optic tract, thalamus, primary visual area of occipital lobe of cerebral cortex.

Front 21

Detached retina

Back 21

Trauma, eye disorders, detachment between neural layer and pigment layer, fluid accumulates and distorted vision and or blindness results.

Front 22

Constriciton of the pupil

Back 22

Autonomic reflex prevents light rays from entering the eye through the periphery of the lens.

Front 23

Refraction of light rays

Back 23

75% bu cornea and 25% by lens (for fine-tuning)
Normal - can refract light rays from an object 6 m/20 ft away.
Myopia, AKA nearsightedness - image focused in front of retina.
Hyperopia, AKA farsightedness - image focused behind retina.
Astigmatism - irregularities on surface of cornea of lens prevent image from being focused on retina.

Front 24

Eyelashes

Back 24

Project from antierior border of each eyelid & Eyebrows- runtransversely above upper eyelids.
Function: protect eyeballs from foreign objects, sweat, direct sunlight
Ciliary (sebaceous) glands - at base of eyelashes' hair follicles; secrete lubricating fluid into follicles.

Front 25

Sensory Tunic AKA Retina

Back 25

Innermost wall; has tow layers:
1.) Pigmented Layer (nonvisual); contains melanin; absorbs stray light.
2.) Neural Layer (visual); multilayered outgrowth of th ebrain; 3 layers of retinal neurons to process visual input from external to internal:
I.) Photoreceptor layer - two types
a.) rods
b.) cones
II.) Bipolar cell layer
III.) Ganglion cell layer

Front 26

Glaucoma

Back 26

Increased intraocular pressue and degeneration of the retina usually resulting in blindness.

Front 27

Excretory lacrimal ducts

Back 27

6 - 12 ducts that drain tears from glands onto conjunctiva of upper eyelid; tears pass medially over anterior eyeball.

Front 28

Eyelids

Back 28

Upper and lowe- consist of Epith. tissue/CT/Muscle tissue.
Functions:
a.) protects eyes from excessive light & foreign objects
b.) lubricate eyeballs
c.) shade eyes during sleep

Front 29

Cataract

Back 29

Loss of transparnecy of lens due to aging, injury, UV light exposure, drugs (steriods), other ds.'s (DM) and leading cause of blindness

Front 30

Superior & Inferior lacrimal puncta

Back 30

2 small openings at medial eye; tears pass into: Superior & inferior lacrimal canals - drains tears into a lacrimal sac which stores and drains tears into the nasolacrimal duct - carries tears into nasal mucosa (cold) which could cause a blockage and cause watery eyes.