Human Eyes Research Paper
Imagine a camera that is composed with 2 million working parts, and stored up to 24 million images around you throughout life span. This incredible amazing camera is our eyes. The human eyes are one of the most interesting medical field that are being studied, as well as one of the most complex organs that has many features. The eyes are the organs of sight and one of our special senses. Vision is our one of our dominant sense: 70% of all the sensory receptors in the body are in the eyes, and almost half of the cerebral cortex is involved in some aspect of the visual processing. Only the anterior one sixth of the eye is visible. (Martini, 2009)
The accessory structures of the eye include the eyebrows, eyelid, conjuctiva, lacrimal apparatus, …show more content…
The follicles of the eyelash hairs are richly innervated by nerve endings, which are hair follicles receptors, and anything that touches the eyelashes, even puff of air, will result in a reflex blinking. There are several types of glands that are associated with the eyelid. The Tarsal, or Meibomian, glands are embedded in the tarsal plates; their ducts open at the eyelid edge just posterior to the eyelashes. As a result, these sebaceous glands produce an oily secretion that lubricates the eyelid and the eye and prevents the eyelid from sticking together. Most sebaceous and modified sweat glands called ciliary glands lie between the hair follicles. (Marieb …show more content…
They originate from the bony orbit and insert into the outer surface of the eyeball. These muscles allow the eye movement and help to maintain the shape of the eyeball and hold it in the orbit. There are four rectus muscles that originate from the annular ring, superior, inferior, lateral, and medial. The function of the oblique muscles is to move the eye in the vertical plane when the eyeball is already turned medially by the rectus muscle. The superior oblique muscles runs along the medial wall of the orbit, and when contracts it rolls the eye downwards and laterally, then makes a right angle turn and passes through a fibrocartilaginous loop perched from the frontal bone known as the trochlea, which insert in the superior lateral surface of the eye. The inferior oblique muscle rotates the eye up and laterally. It originates from the medial orbit surface and runs laterally, and insert on the inferolateral eye surface. These muscles are among the most precisely and rapidly controlled skeletal muscles in the entire body. This reflects their high axon to muscles-fiber ratio: the motor units of these muscles contain only 8 to 12 muscles cells and in some cases as few as 2 or 3. (Marieb
The accessory structures of the eye include the eyebrows, eyelid, conjuctiva, lacrimal apparatus, …show more content…
The follicles of the eyelash hairs are richly innervated by nerve endings, which are hair follicles receptors, and anything that touches the eyelashes, even puff of air, will result in a reflex blinking. There are several types of glands that are associated with the eyelid. The Tarsal, or Meibomian, glands are embedded in the tarsal plates; their ducts open at the eyelid edge just posterior to the eyelashes. As a result, these sebaceous glands produce an oily secretion that lubricates the eyelid and the eye and prevents the eyelid from sticking together. Most sebaceous and modified sweat glands called ciliary glands lie between the hair follicles. (Marieb …show more content…
They originate from the bony orbit and insert into the outer surface of the eyeball. These muscles allow the eye movement and help to maintain the shape of the eyeball and hold it in the orbit. There are four rectus muscles that originate from the annular ring, superior, inferior, lateral, and medial. The function of the oblique muscles is to move the eye in the vertical plane when the eyeball is already turned medially by the rectus muscle. The superior oblique muscles runs along the medial wall of the orbit, and when contracts it rolls the eye downwards and laterally, then makes a right angle turn and passes through a fibrocartilaginous loop perched from the frontal bone known as the trochlea, which insert in the superior lateral surface of the eye. The inferior oblique muscle rotates the eye up and laterally. It originates from the medial orbit surface and runs laterally, and insert on the inferolateral eye surface. These muscles are among the most precisely and rapidly controlled skeletal muscles in the entire body. This reflects their high axon to muscles-fiber ratio: the motor units of these muscles contain only 8 to 12 muscles cells and in some cases as few as 2 or 3. (Marieb