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Thursday, September 29, 2011

Sensory Organs - Eyes and Ears - Medical Terms - LESSON 267

In this lesson, we will learn about important medical terminologies related to eyes and ears. As a learner of free medical transcription course online, one should know about all these terminologies and this will be helpful in doing transcription files online. For every medical terminology, we should know the meaning and a related terminology to it and the meaning of it. In the day to day transcription jobs, every medical transcriptionist will hear these terminologies and so one should be very much familiar with these to be a successful medical transcriptionist. Now we will see about one by one. Okay. Come on.

The first terminology is aque/o, which means water. Aqueous humor is a fluid produced by the ciliary body found in the anterior and posterior chambers. The next one is blephar/o, which means eyelid. Blepharitis is a word that represents inflammation of the eyelid. The other one is conjunctiv/o, which means conjunctiva. Conjunctivitis is a word that means inflammation condition of the conjunctiva.

The next terminology is corne/o, which means cornea. Corneal ulcer is a term, which represents the ulcer of the cornea. The other term is cycl/o, which means ciliary body that is the muscle of the eyes. Cycloplegic means pertaining to ciliary muscle. The next one is dacry/o, which means tear drops. The other term, which means the same is lacrim/o, which also means tear glands. Dacryoadenitis is a word, which means inflammation of the tear glands.

The next important terminology is ir/o, which means iris that is the colored area of the eye, which surrounds the pupil. Iritis is a word that represents the inflammation of the iris. Kerat/o is a term, which means cornea. Keratitis represents inflammation of the cornea. Lacrim/o means tears. Lacrimal is a word, which pertains to the tear glands. Ocul/o means eye. Intraocular is a word that pertains to within eyes.

The next lesson will continue this lesson.

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Sunday, September 25, 2011

Eye Anatomical Terms Explanation - LESSON 266

In the travel of learning free medical transcription course, we are going to learn about anatomical terms explanations of eyes. As a medical transcriptionist student, you should know about all the anatomy and physiology, not like a medical student for surgical purpose, but you should know something basic 
information about them. We explained something in the prior lesson about this topic about what is accomodation, anterior chamber, aqueous humor, biconvex, layer of choroid, ciliary body, cones, conjuctiva, cornea, fovea centralis, fundus of the eyes, lens, iris, macula, optic chiasm, and optic disk. In this lesson, we will learn about, optic nerve, posterior chamber, pupil, refraction, retina of the eyes, rods, sclera, vitreous chamber, vitreous humor one by one. Okay.

Optic Nerve: The other name of optic nerve is cranial nerve 2, which receives and delivers eye sight messages to the brain from the part of cerebral cortex from the retina of the eye.

Posterior Chamber: This is a narrow area behind the iris, which contains a liquid called aqueous humor. Posterior chamber is situated in the front side of the lens's suspensory ligament, as well as ciliary processes.

Pupil: This is a dark hole that situated at the central portion of the iris. The light passes through the eye is taken in by the tissues present here. In simple, pupil is the entrance of the eye.

Refraction: An image is formed inside the eye through the process of refraction. By way of lens and cornea, the entered light rays from the pupil are bended and targeted towards the retina and so we can feel visual sensation of lights.


Retina: This is a tissue lining that is responsive to the light waves that is present inside surface of the eye. Retina consists of color receptor cells called cones and rods.

Rods: These are cells present inside the eye that are photoreceptor cells. Rods are present inside the retina. These rods absorbs mainly black and white waves and so we can see at night.

Sclera: Each eye contains an external coat in the eyeball called sclera, which is very tough in structure. We can see this portion outside and this is also called as 'white of the eye. This hard layer performs as the protective cover of the eye made up of elastic fibers and collagen.

Vitreous Chamber: This chamber occupies about four fold place in five of the eyeball area. This chamber is present between the retina and the lens.

Vitreous Humor: It is a gel-like material present inside the viterous chamber and named as vitreous humor.

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Thursday, September 22, 2011

Anatomical Definitions Of Eye -- Lesson 265

In this post we would come through the definitions shortly.
1. Accommodation: - The adjustment of the eye made normally for looking at objects at different distances. To bring an object into focus on the retina, the lens is made thinner or fatter by the ciliary body.
2. Anterior chamber: -  This is the area behind the cornea and in front of the lens and iris.  Aqueous humor is contained in it.
3. Aqueous humor: - Fluid is produced by the ciliary body and found in the chambers which are anterior and posterior.
4. Choroid layer: - The vascular and middle layer of the eye between the retina and the sclera.
5. Ciliary body: - It is the structure which is on each side of the lens that connects the choroids and the iris. This also contains ciliary muscles, which control the shape of the lens, and secretes aqueous humor.
6. Cones: - The receptor cells which is called photosensitive receptor cells transform light energy into a nerve impulse. Cones are responsible for color and central vision.
7. Conjuctiva: - A delicate membrane lining the eyelids and covering the anterior eyeball.
8. Cornea: - Fibrous transparent layer of clear tissue that extends over the anterior portion of the eyeball.
9. Fovea centralis: - The tiny pit or depression in the retina that is the region of clearest vision.
10. Fundus of the eye: - The posterior and inner part of the eye.
11. Iris: - The colored portion of the eye.
12. Lens: - Behind the pupil of the eye, a transparent biconvex body is situated. It bends light rays to bring them into focus on the retina.
13. Macula: - A yellowish region on the retina, lateral to and slightly below the optic disk; and also contains the fovea centralis.
14. Optic chiasm: - The point at which the fibers of the optic nerve cross in the brain.
15. Optic disk: - The region at the bake of the eye where the optic nerve meets with retina. It is the blind spot of the eye because it contains nerve fibers only and there are no rods and cones and thus this is insensitive to light.
                   
In the next post we would learn some more definitions.

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Eye Anatomical Short Definitions -- Lesson 264

EIn this post we would come through the definitions shortly.
1. Accommodation: - The adjustment of the eye made normally for looking at objects at different distances. To bring an object into focus on the retina, the lens is made thinner or fatter by the ciliary body.
2. Anterior chamber: -  This is the area behind the cornea and in front of the lens and iris.  Aqueous humor is contained in it.
3. Aqueous humor: - Fluid is produced by the ciliary body and found in the chambers which are anterior and posterior.
4. Choroid layer: - The vascular and middle layer of the eye between the retina and the sclera.
5. Ciliary body: - It is the structure which is on each side of the lens that connects the choroids and the iris. This also contains ciliary muscles, which control the shape of the lens, and secretes aqueous humor.
6. Cones: - The receptor cells which is called photosensitive receptor cells transform light energy into a nerve impulse. Cones are responsible for color and central vision.
7. Conjuctiva: - A delicate membrane lining the eyelids and covering the anterior eyeball.
8. Cornea: - Fibrous transparent layer of clear tissue that extends over the anterior portion of the eyeball.
9. Fovea centralis: - The tiny pit or depression in the retina that is the region of clearest vision.
10. Fundus of the eye: - The posterior and inner part of the eye.
11. Iris: - The colored portion of the eye.
12. Lens: - Behind the pupil of the eye, a transparent biconvex body is situated. It bends light rays to bring them into focus on the retina.
13. Macula: - A yellowish region on the retina, lateral to and slightly below the optic disk; and also contains the fovea centralis.
14. Optic chiasm: - The point at which the fibers of the optic nerve cross in the brain.
15. Optic disk: - The region at the bake of the eye where the optic nerve meets with retina. It is the blind spot of the eye because it contains nerve fibers only and there are no rods and cones and thus this is insensitive to light.
                   
In the next post we would learn some more definitions.

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Sunday, September 18, 2011

The Eye -- Its Anatomy and Physiology III -- Lesson 263

In the recent post you have learned about the rods and cones.An optic nerve is the nerve of which light energy is focued on the retina, a chemical change occurred in the rods and cones initiating nerve impulseswhich travel from the eye to the brain via the optic nerve. The region in the eye where the optic nerve meets the retina is called retina is called the optic disk. This optic disk is otherwise called as the blind spot of the eye. A small oval which is called the macula is yellowish area to the side of the optic disk.

 A central depression which is called fovea centralis is also contained in it. which composed of largely of cones, and is the location of sharpest vision in the eye.  If fovea's portion or macula's portion is damaged, central vision blindness occurs and the vision is reduced. Through the opthalmoscope the fundus of th eye is the posterior and the inner part is visualized. 

The rods and cones in the retina synapse with neurons and leads to the optic nerve fibers. As the optic nerve fibers travel into the brain, the fibers located more medially cross in an area called the optic chiasm. From the right half of each retina nerve fibers form an optic tract, synapsing in the thalamus of the brain and ending in the right visual region of the cerebral cortex. In the same way, fibers from the left half of each retina merge to from the optic tract and pass from the thalamus to the left region of the cerebral cortex. 

The images are fused in the visual area of the cerebral cortex and a single visual sensation with a three-dimensional effect is experienced. This vision is called binocular vision. Loss of vision in the right visual field is caused due to the damage in the left cerebal cortex. This vision loss in the contralateral or opposite side of the visual field is called hemianopsia, in which hemi means half, an means without, opsia means vision.

In the next post we would learn the short definitions related to this topic.


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Friday, September 16, 2011

The Eye – Its Anatomy and Physiology II -- Lesson 262

The ciliary body secretes a fluid called aqueous humor other than the shape of the lens. This fluid flows through the anterior chamber and posterior chamber of the eye. The fluid remains constant and that is produced and leaves the eye through a canal which carries it into the bloodstream. Vitreous chamber is the other cavity of the eye, which is a major region behind the lens which is filled with soft, jelly-like material. This vitreous humor regulates the shape of the eyeball and is not perfectly formed again. Blindness can be caused due to escape from the eye. To further refract light rays, both these humors (aqueous and vitreous) function.

The thin, delicate and sensitive nerve layer of the eye is retina. This retina is a layered structure with many layers of neurons interconnected by the synapses. Light energy, which is in the form of waves travels through the eye, it is refracted by the cornea, lens and fluids. Cone-rod dystrophy explains a number of diseases where the loss of vision is caused by the deterioration of cones or rods in the retina. The light focuses on sensitive receptor cells of the retina which are called the rods and cones. There are nearly 6.5 million cones and 120 million rods in the retina. These cones are mainly found in the central area of the retina. Rods are super-sensitive; cones are most useful in normal and bright light. These cones are responsible for color and central vision. The cones are of three types and each type is stimulated by one of the primary colors in red light, green light or violet light. Generally in most of the cases of color blindness affect either the green receptors or red receptors, so that the two colors cannot be distinguished from each other. These rods function at reduced levels of light and are merely responsible for peripheral vision. Sensitivity of the rod is shifted towards shorter wavelengths when compared to day wavelength.

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Sunday, September 11, 2011

The Eye – Its Anatomy and Physiology -- Lesson 261

Light rays pass through the dark center of the eye, called the pupil. The mucous membrane which is called the conjunctiva that lines the eyelids and coats the front portion of the eyeball over the white of the eye. The conjunctiva is very blur and colorless except when blood vessels are dilated. Dust or smoke may cause to dilate the blood vessels and give the conjunctiva an appearance of red which is generally known as bloodshot eyes.

The cornea which is a fibrous, transparent tissue that extends over the pupil and colored eye portion. The cornea works as it bend, or refract, the rays of light; so that they are indented properly on the cells of the sensitive receptor in the region of the eye which is posterior. The cornea is a vascular which has no blood vessels but receives its nourishment from blood vessels near its junction with the white of the eye, the selera. For people with scarred or opaque corneas are successful corneal transplants because the cornea has no supply of blood and rejection of foreign tissue is made with the response of antibodies which do not reach it. The sclera which is a fibrous, tough, supportive, connective tissue that extends from the cornea on the front surface of the eyeball to the nerve which is optic in the back of the eye.

Inside the sclera, there is a dark brown membrane called the choroid. This contains many blood vessels that supply nutrients to the eye. The choroids is continuous with the pigment containing iris and on the anterior surface of the eye called the ciliary body.

The iris which is colored can appear blue, green, gray, hazel or brown portion of the eye that rounds the pupil. The iris constrict the pupil in bright light of the muscles and dilate the pupil in dim light thereby regulating the amount of light entering the eye.

On each side of the lens, the ciliary body contains muscles that can adjust the shape and thickness of the lens. The refraction of light rays in the shape of the lens aid these changes. The lens is thinned or flattened for distant vision and thickened for close vision by the muscles of the ciliary body. This refractive power of the lens is called accommodation.

In the next post we would learn further about the eye’s anatomy and physiology.

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Sunday, September 4, 2011

Sense Organs: The Eye And The Ear -- Lesson 260

In the recent chapters we have learned about the sense organs; the eye and the ear. Now in this chapter we would learn about in brief and recall the points.The sensitive nerve endings in the corium layer of the skin receive impulses from stimuli of various kinds and applied to the external surfaces of the body. These nerve endings transmit electrical messages, initiated by the stimuli, to regions of the brain (cerebrum and thalamus) so that we can able to identify sensations through temperature, touch, pain, and pressure. The nerve cells which carry impulses from a sense organ or sensory receptor area, such as the skin, tastebuds, and olfactory regions which are also called centers of smell in the nose, to the brain are called afferent sensory neurons.

We already came across through the eye and the ear which are the sensory organs, like the skin, taste buds, and olfactory regions. Because these are receptors, whose sensitive cells may be activated by certain form of enrgy or stimulus by starting a series of nerve impulses along afferent sensory neurons that lead to the brain.
The kind of stimulus is applied to a particular receptor, the sensation we felt is identified by the regions in the brain that are connected to that receptor.

Thus, mechanical injury that might stimulate receptor cells in the eye and the ear would produce sensations of vision also called flashes of light adn sound. In the same way, if one could make a nerve connection between the sensitive receptor cells of the ear and the area in the brain associated with sight, it would be possible to perceive, or "see," sounds. We can realize the general pattern of events when such stimuli as light and sound are applied to sense organs such as the eye and ear.

Stimulus (applied to) Receptor cells in ear and eye (which excited to ) afferent nerve fibers (which carry impulse to) brain where nerve impulses are translated into sound sensations and visual images.

In the next chapter we would learn about the anatomy and the physiology of the eye.

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The Longest Medical Word

Today, we will know about an interesting medical term in medical language. This post is just to know about a different thing in the medica...