Mahatma Jyotiba Fule College of Veterinary Science

and Animal Husbandry, Chomu (Raj.)

PRESENTED BY:

Dr. Lakshmi kant

2019-2020

Assistant professor

DEPARTMENT OF VETERINARY ANATOMY AND HISTOLOGY

COLLEGE OF VETERINARY SCIENCE & ANIMAL HUSBANDRY,

CHOMU (RAJ.)

EMBRYOLOGY OF EYE

The eye or the organ of sight is situated inthe orbital cavity of the skull.

It is well protected by bony walls of the orbit

Orbit also contains muscles of eyeball, theirnerves, blood vessels, and lacrimal gland.

Each eyeball is similar to a camera and whichproduces images.

EYEBROWS

EYELIDS & EYELASHES

LACRIMAL APPARATUS

CONJUNCTIVA

STRUCTURE OF THE EYEBALL

1. Wall of eye ball

2.Light transmitting media (or) refractive media

:

OUTER LAYER (FIBROUS COAT) : SCLERA AND CORNEA

MIDDLE LAYER (VASCULAR COAT) : CHOROID ,CILIARY-BODY AND IRIS

INNER LAYER (NERVOUS COAT) : RETINA

OUTER LAYER (OR) TUNICA EXTERNA (OR) TUNICA FIBROSA

This gives shape of eyeball and contains scleraand cornea

This layer comprises of three structures:,

•Choroid•Ciliary body•Iris

The choroid, ciliary body and iristogether form the uveal tract.

This layer contains blood vessels

Pupil is the small opening in front of it.

Retina is the light sensitive membrane.

Neural Crest

Neural crest

Corneal keratocytes,

Corneal endothelium

Trabecular meshwork,

Stroma of the iris andchoroid,

Ciliary muscle,

Fibroblasts of the sclera, the vitreous, and the optic nerve meninges.,

Extraocular muscles,

Subepidermal layers of the eyelids.

Surface ectoderm

lens

the lacrimal gland

the epithelium of thecornea

conjunctiva

epidermis of theeyelids

Neuro ectoderm

optic vesicle and optic cup

Retinal pigmentepithelium

Ciliary epithelium

Iris muscles

optic nerve fibers and glia.

Mesoderm

Vitreous

Extra ocular & lid muscles

Orbital and ocular vascular endothelium

3 to 4 week stage of embryo

2nd month stage of embryo

j

3rd month stage of embryo

4th month stage of embryo

5th month to birth

Anterior – posteriordiameter : 16.5 mm

Anterior chamber – shallow

Lens - spherical

Cornea diameter = 10 mm

Orbit is divergent to 50degrees

Myelination occurs till lamina cribrosa

Retina except macula is fullydifferentiated and formed

Fixation completed by 6 months

Macula formed by 6 months

Steropsis and accomadation by 6 months

Cornea reaches adult size by 2 years

Lens develops throughout life

It develops from the opticcup.

The outer layerof the optic cup is the pigment layer.

The neural layer is formed from the inner layerof the optic cup.

Develops from glial cells of neuro-ectodermal

cells and axons from ganglion cells with meningeal

coverings forming the optic nerve sheets.

The posterior wall begin to elongate anteriorly

and form long fibers that gradually fill the lumen of

the vesicle.

Migration of neural crest cells

1 st wave – corneal and trabecular endothelium

• 2 nd wave - corneal stroma

• 3 rd wave - Iris stroma

Primary vitreous

Secondary vitreous

Tertiary vitreous

SCLERA :

This fibrous coat is formed from thecondensation of the mesenchyme around theoptic cup.

CHOROID:

This inner vascular layer is formed fromthe mesenchyme surrounding the opticvesicle.

Ciliary glands and eyelashes develop as

outgrowths of epithelial buds.

Eyelid develop from surface ectoderm.

Lacrimal glands develop as ectodermal buds

supero-laterally into mesenchyme.

Lacrimal sac and nasolacrimal duct developfrom ectoderm - naso-lacrimal furrow which getsburried into a cord.

Part Derived from

Lens Surface ectoderm

Retina Neuroectoderm (optic cup)

Vitreous Mesoderm

Choroid Mesoderm (infiltrated by neural crest cells)

Ciliary body Mesoderm

Ciliary muscles Mesenchymal cells covering the developing ciliary body (neural crest)

Iris Mesoderm

Muscles of the iris Neuroectoderm (from optic cup)

Sclera Mesoderm (infiltrated by neural crest cells?)

Cornea Surface epithelium by ectoderm, substantia propria and inner epithelium by neural crest

Conjunctiva Surface ectoderm

Blood vessels mesoderm

Optic nerve Neuroectoderm. Its covering (pia, arachnoid and dura) are derived from mesoderm

26) In all the flexor muscles of forelimb except ulnaris lateralis,

median nerve is the main nerve supply.

27) For ulnaris lateralis, radial nerve is the main nerve supply.

28) The left axillary artery arises from the brachiocephalic trunk

opposite to the 2nd intercostals space and the right one

arises opposite to the 1st rib.

29) Brachial plexus is formed by the convergence of ventral

rami of 6th, 7th and 8th cervical spinal nerves and 1st and

2nd thoracic spinal nerves.

28)Thoraco dorsal nerve of brachial plexus ramifies into

the latissimus dorsi muscle of shoulder girdle.

29) Radial nerve is the largest of all branches of brachial

plexus.

30) Musculocutaneous branch and median nerve of

brachial plexus form a primary loop.

31)The pulse rate in dog is taken by cephalic artery in fore

limb and saphenous artery in hind limb.

32) In all the extensor muscles of forelimb, radial nerve is

the main nerve supply.