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In our previous anatomy and physiology session we have discussed about Lung Anatomy, Function and Disease, Anatomy of Kidney, Functions of Kidney, Anatomy of Liver, Functions of Liver, Anatomy of brain, Gait Cycle. Please check out for the link below.
Lung Anatomy, Function and Disease
Being a healthcare professional, it is very important to have knowledge about human eye.
In today’s topic we are going to discuss about anatomy of the eye.
Let's get into the topic.
ANATOMY OF THE EYE
The eyes are the organs of sight. The eyes are about
an inch in size. The eyes are complex organs which are made up of many parts.
The anatomy of eyes includes cornea, pupil, iris, sclera, conjunctiva, lens,
retina, optic nerve, macula, choroid and vitreous body.
Let’s discuss in detail about each part of the eye.
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CORNEA
The cornea is the front window of the eye. A clear
dome over the iris. The cornea transmits and focuses the light into the eye.
IRIS
The iris is the coloured part of the eye which helps
to regulate the amount of light that enters into the eye. When the light is
low, the iris opens up the pupil to let more light into the eye. When the light
is more, the iris closes to let less amount of light into the eyes.
PUPIL
The pupil is the dark aperture present in the iris
which determines how much light is let into the eyes. The pupil changes its
size to alter the amount of light entering into eyes. The size becomes smaller
for brighter light and larger for low light.
SCLERA
The sclera is the dense
connective tissue of the eyeball which forms the white visible portion of the
eyeball. The muscle that moves the eyeball are connected to sclera. The sclera
is a tough covering with which the cornea forms the external protective coat of
the eye. The sclera continues with the stroma layer of the cornea. The
thickness of the sclera ranges from about 0.3mm to 1.0mm
CONJUNCTIVA
The conjunctiva is a
clear, thin membrane which covers a part of front surface of the eye and inner
surface of the eyelids. The main function of the conjunctiva is to keep the
front surface of the eye moist and lubricated. The conjunctiva has two
segments, bulbar conjunctiva and palpebral conjunctiva.
The bulbar conjunctiva
covers the anterior part of sclera. It stops at the junction between sclera and
cornea. It does not cover cornea.
The palpebral conjunctiva
covers the inner surface of both upper and lower eyelids.
LENS
The lens in the eye is
used to focus the light onto the retina. The lens is a transparent structure
located directly behind the pupil. The lens which is enclosed in a thin
transparent capsule helps in automatic focus of near and approaching objects
through a process called accommodation. It acts as an autofocus camera lens.
The Cataract is a problem
when lens become cloudy which can be corrected by replacing cloudy lens with
artificial plastic lens.
RETINA
The retina is a light
sensitive nerve layer which makes the inner lining located on the back of the
eyeball. The retina converts optical images into electronic signals. The retina
has two types of photoreceptor cells, the rods and cones.
The rods react well in
low light providing black and white vision. The human eye contains about 125
million rods. The cones react in medium and bright light providing central and
colour vision. There are about 6 to 7 million cones in the eye.
OPTIC NERVE
The retina sends light as
electrical signals through the optic nerve to the brain. The optic nerve is
made up of millions of nerve fibres which transmit these impulses to the brain.
MACULA
The macula is the central
part of retina which contains the special light sensitive cells. These light
sensitive cells allow us to see the finer details clearly in the centre of
visual field.
CHOROID
The choroid is a layer of
the eye containing blood vessels which lines the back of the eye. The choroid
is located between the retina and the sclera.
VITREOUS BODY
The vitreous body is a
clear, jelly like substance which fills the back part of the eye.
Now I hope you have acquired some knowledge about Anatomy of the eye. We will meet again with another valuable healthcare topic.
NOTE: Dear friends!!!... Please do comment a topic related to Biomedical, so that we can discuss it in future blogs.
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