The external ear consis of two parts, the auricula or pinna – a funnel shaped organ with its muscles, which collects the sound waves and the external acoustic meatus, which conveys these waves to the drum of the ear which separates the external ear from the middle ear. The auricula or pinna is the visible […]

Ear is the organ of hearing, it divided in three parts- External ear, middle ear and internal ear. Ear have these parts to read further- External Ear Middle Ear Internal Ear Osseous Labyrinth Membranous Labyrinth Microscopic Structure of Membranous labyrinth

The Refractive media of eye include the cornea, the aqueous humor in the anterior and in posterior chambers, the lens and the vitreous humor. The cornea is described earlier in the fibrous tunic. The aqueous humor is a clear fluid of an alkaline reaction, consisting chiefly of water with a trace of albumin and chloride or sodium. It fills the anterior and posterior chambers of the

The Retina of eye or Nervous tunic forms the innermost tunic of the eyeball and extends from the entrance of the optic nerve to the iris. It consists of three parts; a posterior part the essential region containing the special neuroepithelium, the pars optica retinae. This terminates around the ciliary body where it ends in a regular

Iris of eye is a muscular diaphragm placed in front of the lens and is visible through the cornea. It is pierced centrally by an elliptical opening, the pupil. The ciliary border is continuous with the ciliary body and is connected with the ligamentum pectinatum iridis. The pupillary border surrounds the pupil. The upper margin

Ciliary body of eye is the middle part of the vascular tunic and connects the chorioid with the periphery of the iris. In meridional section, it is triangular in outline with the base next to the iris. It consists of three parts, ciliary ring, ciliary processes and ciliary muscle. The ciliary ring is continuous with the anterior part

Choroid of eye ball is a thin membrane lying between the sclera and retina. It is loosely attached to the sclera by the lamina fusca except where vessels and nerves pass through. The internal surface is in intimate contact with the pigmentary layer of the retina. The chorioid is generally dark brown in colour but

The Sclera of eye ball is a dense white fibrous membrane forming about four fifths of the fibrous tunic of the eyeball. Thickest in the vicinity of the posterior pole, it thins at the equator and increases in thickness toward the junction with the cornea. It is often pigmented. When non-pigmented it shows a bluish

The cornea forms the anterior one fifth of the fibrous tunic. It is transparent, colorless, and avascular. It is oval, the broad end being medial. The anterior surface is convex and more curved than the sclera. The posterior surface is concave and forms the anterior boundary of the anterior chamber. The margin joins the sclera where the sclera overlaps

The tunics are three in number-external fibrous, middle vascular and internal nervous. Fibrous tunic of eye ball The fibrous tunic is composed of an anterior transparent, avascular part called the cornea and a posterior opaque, vascular part known as the sclera.