Sensory Organ: Eye-2

Compartment of the Eye:

The anterior cavity, which is in front of the lens, and the posterior cavity, which is behind the lens, are separated by the lens. Both of these cavities are filled with fluid, which works to keep the eyeball in its regular shape, to maintain intraocular pressure, and to help refract light, or bend light rays so they focus on the retina.

The watery fluid in the eye's front cavity is known as aqueous humor, while the jelly-like fluid in the eye's posterior cavity is known as vitreous humor. In the anterior cavity, aqueous humor is continuously produced, drained, and refilled. If the drainage is stopped for whatever reason, the internal pressure will rise, causing damage that can result in blindness. The name of this condition is glaucoma.

The lens is a flexible, translucent, biconvex structure that is devoid of blood vessels. Directly behind the pupil is the lens. The lens is composed of crystalline proteins, a unique group of proteins, which are encased in an elastic, transparent capsule. The suspensor ligaments joined to the ciliary muscle suspend it between the two eye compartments.

Accessory Structures of the Eye

Accessory structures lubricate, shield, and facilitate eye movement. They include:

• Eyebrows
• Eye lids
• Conjunctiva
• Lacrimal apparatus
• Extrinsic eye muscles

Eyebrows:

Above the upper eyelids, there are short hairs called eyebrows.

The Purposes of the Brows:

• They shield the eyes from sweat by preventing it from dripping from the forehead.
• They shield the eyes from external objects as well.
• They protect the eyes from the sun.

Eye Lids:

The eyelids, also known as palpebrae, are tiny tissue folds that cover the eyes to shield them from dust and too much light. The medial and lateral canthi, which are located at the medial and lateral angles of the eye, are where the eyelids meet. The nasal bone is close to the medial canthus, which is wider. The caruncle, a little reddish-pink elevation that houses sweat and sebaceous (oil) glands, is present on it.

Seven layers of tissue make up the eyelids, arranged from the outer to the inner surface as follows:

• A thin layer of skin covering the outside.
• A thin layer of connective tissue at the areola.
• Skeletal muscular tissue (i.e. the orbicularis oculi and levator palpebrae superioris muscles).
• Nerves, blood arteries, and loose connective tissue make up the layer of submuscular areolar tissue.
• The tarsal plate is a layer of connective tissue that aids in maintaining the shape of the eyelid.
• Muller's palpebral muscle makes up the layer of non-striated muscle.