Aesthesiology (Sense organs) - PowerPoint Presentation

Slide1

Aesthesiology (Sense organs)

Sense organs include:

Eye : Organ for vision

Ear: Organ for hearing

Nose: organ for smell

Skin: Sense for touch, heat and cold.

Tongue: Sense for taste. Slide2

EYE

Eye in general consisting of:

(1) Eye ball and

(2) Accessory structuresSlide3

Major Layer and Chambers of eye Ball

Eye ball consisting of three layer:

Fibrous tunic: Sclera and Cornea

Vascular layer: Ciliary body, Ciliary process, Iris.

Nervous layer: Retina.

Chambers of the eye ball:

Anterior chamber: In between cornea and iris.

Posterior chamber: In between iris and lens

Vitreous body: In between lens and retina.Slide4

Accessory Structure of Eye Ball

Muscles of the eye ball:

(a) 4 rectus muscles: Dorsal rectus, Ventral rectus

Lateral rectus and Medial Rectus

(b) 2 Oblique: Dorsal oblique and ventral oblique

(c) Retractor

oculi

2.

Periorbital

fat.

3. Nerves:

Optic,

Occulomotor

,

Trochlear

,

Opthalmic

, and

Abducent

.

4. Optic artery and vein.

5. Lymphatic channels, and,

6.

Lacrimal

apparatus:

Lacrimal

gland, duct, sac,

naso-lacrimal

duct.

7. Eye lid: Upper and lower eye lid.

8. Conjunctiva:

Palpebral

and bulbar

conjuctiva

. Slide5

Structure of the Eye BallSlide6

Fibrous Tunic of Eye Ball

The fibrous tunic is the outer most layer of the eye ball, gives the shape of the eye ball and consist of dense

collagenous

fiber. The fibrous tunic consist of:

Sclera

: Posterior three-quarter of the eye ball, whitish and tough.

Cornea:

Anterior transparent part is the cornea.

Sclera and cornea meet anteriorly at

corneo-scleral

junction or

limbus

.Slide7

Vascular Layer of the Eye Ball

The vascular layer consist of three layers:

Choroid (2) Ciliary body and (3) Iris

Function

:

Blood supply, suspension and regulation of the shape of the lens, regulation of the size of the pupil, and production of aqueous humor

.

Choroid:

It is pigmented, highly vascular layer and envelop the posterior part of the eye-ball. Near the optic papilla it consist of half moon-shaped area

the

tapetum

.

Ciliary body:

Thickest middle segment between choroid and iris. It consist of

ciliary process

and

zonular

fiber

. Ciliary process is responsible for formation of aqueous humor and

zonular

fiber connects with the lens and controls shape of the lens.

Iris

: It is the anterior most part of the vascular layer and act as a muscular diaphragm between cornea and lens. It forms the pupil. Slide8

Nervous Layer of the Eye Ball

It is the innermost layer of the eye ball where light reflect and forms images. It consist of ten histological layers. Optic nerve innervates into this layer.Slide9

Inner Structure of Eye Ball (Lens and Chambers)

Lens of eye ball

: The lens is a transparent biconvex structure and suspended in the eye by

zonular

fibers. The posterior surface is more convex than the anterior. The convexity changes for the accommodation of light. It receives nutrition from aqueous and vitreous humor.

Eye has three chambers

:

(a)

Anterior (b) Posterior and

(c) Vitreous Chamber.

(a) Anterior Chamber

: It is bounded anteriorly by cornea and posteriorly by Iris and lens. It is communicated to the posterior chamber through the pupil. Slide10

Posterior Chamber and Vitreous Chamber

Posterior chamber

: It is bounded anteriorly by iris and ciliary body and posteriorly by lens. It is filled up with aqueous humor.

Vitreous Chamber

: It is bounded anteriorly by lens and ciliary body. The rest of the vitreous chamber is enclosed by the retina. It is filled by viscous jelly like mass called vitreous humor/vitreous body.Slide11

Chambers and Lens of Eye Ball

Cornea

Lens

Ant. Cham

.

Posterior

Chamber

Ciliary

Process

Sclera

Iridocorneal

Junction

Formation, circulation and

drainage of aqueous humor:

Active

secretory

process from the epithelium of the

ciliary

body

Aqueous humor circulate through-

o

ut the posterior chamber

Pass through the pupil

Aqueous humor enters into the anterior

chamber and circulate throughout it

Finally drain through the

iridocorneal

junction into venous circulationSlide12

Formation, Circulation and Drainage of Aqueous Humor

Aqueous humor produced by an active

secretory

process from the epithelium of the ciliary body. It is clear and colorless fluid containing several electrolytes, amino acids, glucose and ascorbic acid.

It flows from posterior chamber to the anterior chamber through the pupil and drains through the iridocorneal junction into the venous plexus. Impairment of the flow and drainage of aqueous humor results in

Glaucoma.

It increases intraocular pressure resulting

retinal atrophy and blindness.

We can diagnose it by the protrusion of the eyeball

.

Function of aqueous humor:

It provides nutrition to the cornea and lens.Slide13

Lacrimal apparatus

Lacrimal

gland &

Excretory duct

Lacrimal

canalicu

li

Lacrimal

sac

Nasolacrimal

duct

Lacrimal

gland (

tear gland

)

secretes

lacrimal

fluid

, excrete

into the

conjunctival

sac

. From

here through

lacrimal

can

aliculi

i

nto the

lacrimal

sac

and finally

via the

nasolacrimal duct drains into the nasal cavity.

Composition: Water, salt andFew electrolytes. Any defect in the secretoryMechanism leads to “dry eyeSyndrome”.