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Anatomy and physiology ch.8 the eye
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Structures of the eye and ear
We use our ears for the hearing sense, and we use our eyes for vision.
Both are very important senses and would be hard to get along without.
We rely on hearing for communication, navigation, entertainment and many
other purposes
Now for our eyes we use them for vision, their like our own personal camera’s,
both have and use lens to focus on images.
The eyes respond to the visible spectrum, this spectrum is made up of
wavelengths of different sizes. The shorter waves produce a purple color, while
Longer wavelengths produce blue, yellow, green and orange, and the longest
Waves are red. Saturation, brightness, and hue all are components used in the
Visible spectrum.
More than half of the sensory receptors in the body happen to be
located in the eyes, also the cerebral cortex plays a large role in processing
Visual information.
Some accessory structures of the eye are: the eyelids, eyelashes, eyebrows,
Lacrimal apparatus, and the extrinsic eye muscles. The eyelids or (palpebrae)
Are used for shade, whether it’s for sleeping or from excessive light, or from
foreign objects that don’t belong in the eye. While the eyelids are protecting
The eye it also helps at the same time by spreading lubricates over the eyeballs.
The eyelashes help protect from foreign objects and perspiration, as well do the
Eyebrows . The Lacrimal apparatus is a group of small structures, when humans
Express emotions with tears, the Lacrimal apparatus helps to produce and then
Drain those tears away. There are six extrinsic eye muscles to help move each
Eye; the superior rectus, inferior rectus, lateral rectus, medial rectus, superior
oblique and inferior oblique. Circuits in the brain stem and cerebellum tell these
muscles what to do.
The structure of the eye begins with the fibrous tunic, vascular tunic
And the retina. These are all on the wall of the eyeball, the fibrous tunic consist of
the cornea and the sclera. The cornea is what covers the iris, and is the
outermost layer of the eye through which light passes. The sclera or the “white”
of the eye, this is what gives form to the eyeball. The vascular tunic has three
parts to it; the choroids, ciliary body, and the iris. The choroids is what provides
nutrients to the surface of the retina. The ciliary body consist of ciliary muscle
and the iris which is the colored part of the eye, it regulates the amount of light
Special care was given to the eyes to "express his wisdom and the depth of his psyche (El-Shahaway, 83 ). " The eyes are made of red-veined white magnesite. A hole is drilled into the iris to display a pupil.----- Furthermore, the eyes provide
of as an inner ear. It is now thought to be made up of two components
Eyes are the ‘organ of sight or vision; the visual sense; the sense of seeing’ (Biology-Online). The eye is an organ that detects light and sends signals along the optic nerve to the brain. The eye allows for light recognition and the ability to differentiate between colors, and light and dark. The eye is approximately 2.54 cm wide, 2.54 cm deep and 2.2 cm tall. The human eye has around 200-degree viewing angle and can see and detect more than 10 million colors and shades. This essay is going to look at ways of seeing. The possible problems with eyesight, and eyes of various kinds. It is one of the most rare problems today that is affecting people, all over the world. Around the world an estimate of 4 in 10 people have perfect vision/sight (BBC). The population of the world right now
The fovea in the center of the retina contains the greatest density of optical receptor in the retina. Consequently we perceive objects in much greater detail in the center than in the peripheral vision. To make things more extreme, all the receptors in the fovea are cone or color receptors so you get your best color vision right in the center.
two pleural lobes on the sides. The three main parts of it's body are called the
The iris is the name of colored part of the eye. Inside the iris is the pupil, and surrounded by it is the sclera. In Greek mythology, Iris was the name of the goddess of the rainbow. She was also a messenger to the gods. Iris was also responsible for replenishing the Earth with tranquility after a time of disruption. Inside the eye, the iris had gotten its name because it is full of color and hue, representing many shades in the rainbow, which the goddess Iris was in charge of.
Sight is the capability of the eyes to focus and detect images, hearing or audition is the sense of sound perception, taste refers to the capability to detect the taste of substances such as food, smell refers to the capability of detecting odors and touch responds to pressure receptors. There are about 6 million specialized cells just for smelling. Separate senses with their own receptor organs, taste and smell are nonetheless intimately entwined. This
The four main components of the eye that are responsible for producing an image are the cornea, lens, ciliary muscles and retina. Incoming light rays first encounter the cornea. The bulging shape of the cornea causes it to refract light similar to a convex lens. Because of the great difference in optical density between the air and the corneal material and because of the shape of the cornea, most of the refraction to incoming light rays takes place here. Light rays then pass through the pupil, and then onto the lens. A small amount of additional refraction takes place here as the light rays are "fine tuned" so that they focus on the retina.
Laila confirms that her friends have ordered pizza using her visual system. Through the sensation of light, sensory information is processed and Laila is then able to see the pizza. The pupil absorbs light, by allowing light to enter the eye, and light will then be transferred to the lens. The lens is responsible for refracting light and focusing the light inside of the eye, also known as the retina. The second cranial nerve, or optic nerve, is responsible for carrying the visual signal from the eye to the optic chiasm. The optic nerve, or second cranial nerve, is located in the back of the eye. This cranial nerve transfers visual information to visual centers in the brain through many electric impulses. The optic chiasm has temporal fibers that travel ipsilaterally as nasal fibers transmit information contralaterally, to the opposite side of the associated visual field. The visual cortex can then process sensory information from the opposite eye. Laila’s blind spot is where the optic nerve begins and there are no rod or cone cells in the optic nerve. The brain has to try to compensate for the lack of photosensitive
An inspection of the modern animal phyla will reveal that eyes are just as diverse as they are complex. Some organisms like the rag worm have pigmented cup eyes while other like he box jellyfish have two lens eyes and two pairs of pigment pit eyes. To account for the diversity in eye structure, we must first examine the eye ‘prototype’, the original structure that was acted upon by evolution. The simplest organ that can be considered an eye is composed of a single photoreceptor cell and a single pigment cell, without any lens or other refractive body (Arendt, 2003). Such organs are know as eyespots, and...
One sub-system under the sensory system is the visual system; the main sense organs of this are the eyes. The eye is the sensory organ that allows us to detect light from external stimuli. When a light ray is detected, the eye converts these rays into electrical signals that can be sent to the brain in order to process the information and giv...
There are three simple tissues namely, parenchyma, collenchyma, and sclerenchyma. Parenchyma is thought of as the ground tissue of an axis since it occurs in greatest abundance and is the tissue in which the vascular tissues are embedded. Parenchyma cells may be isodiametric in both the pith and the cortex, but are more mostly longitudinally elongated in the cortex. They have comparatively thin walls. Wall layers are continuously shaped regions. These simple pits usually occur opposite each other, forming pit-pairs in the walls of contiguous cells. Plasmodesmata (specialized strands of endoplasmic reticulum) form interconnections with the protoplasts of adjacent living cells through simple
Visual perception plays a big part on how we perceive life. If we didn't have perception I don't know where we would be now.
The ear is an organ of the body that is used for hearing and balance. It is connected to the brain by the auditory nerve and is composed of three divisions, the external ear, the middle ear, and the inner ear. The greater part of which is enclosed within the temporal bone.
This protects the eye from becoming dry.The Cornea, a part of the sclera, is the transparent window of the eye through which light passes. The focusing of the light begins in the cornea.Behind the Cornea is a watery fluid called the aqueous humor. This fluid fills a curved, crescent shaped space, thick in the center and thinner toward the edges. The cornea and the aqueous humor together make an outer lens that refracts, or bends, light and dire...