HIsto

Revision~!
Ohyeah~!
THere's 2 type of sentient organ~
primary sentient organ and secondary sentient organ~
Primary sentient organ includes eyes,nose.
Secondary sentient organ include ear and taste~
so..now we look at the primary sentient organ -eyes~
firse of all~
eyesball compose of 3 layers~
1st : coneoscleral coat(outer most layer)
2nd : vascular layer (middle layer)
3rd : retinal layer (innermost layer)

corneosclreal layer can be subdivided to 3 parts:
(a) Cornea
(b) scleral
(c) white portion

(a) Cornea~(it's transparent)
main function: Image formation
There's 5 layer for it
(1) Stratified squamous epithelim
(2) bowman's membrane-provide stability and strength
(3) Stroma
(4) Descement's membrane
(5) Endothelium
=cornea receive nutrient from aqueous humour through simple diffusion
=avascular(no BV)
=It's transparent .. y?
because arrangement of fibrous elements,unique composition of glycosaminoglycans and lack of BV.
=Glaucoma may occur when increase in intraocular pressure due to obstruction that prevent drainage of aqueous humor.
- fot the the 1st layer,stratified squamous epithelium
**it have healing and regeneration process where if it's minor wound it will hearl by cell migration,if it's large wound it will undergo mitosis in basal layer~
**it is bath by tears which contain lysozyme for antibacterial enzyme


(b) Sclera
main function: to maintain eyes shape
-attach to muscle(eye rotate freely and changing visual field)

2nd part: vascular part can be divided into 3 part:
(A) Choroid
(B) Iris
(C) stroma of ciliary body