Anglický jazyk
5.3 Medical English - Sense organs
Humans just as any other animals have 5 senses: sight (vision), hearing (audition), taste, touch (sensation or feeling), and smell (olfaction). The functions of these senses are provided by sense organs. For vision it is the eyes, for audition it is the ears, for taste it is the taste buds, for touch it is the skin, and for smell it is the olfactory regions in the nose.
There are receptors in the sense organs whose sensitive cells are activated by a particular form of energy or stimulus in the external or internal environment. The sensitive cells respond to the stimulus by initiating a series of nerve impulses towards afferent sensory neurons which lead to the according region in the brain.
Sight is probably the most important sense for humans. We receive up to 80% of information from the outer world by eyes. People who have impaired sight might be blind. Other symptoms might be double vision (diplopia) or blurring (loss of clarity) often connected with a glaucoma or cataract.
The black center of the eyes is called the pupil. It can dilate or constrict. Light rays pass a mucous membrane called the conjunctiva and a transparent fibrous membrane called the cornea and enter the eye. The cornea bends or refracts the rays of light so that they are focused properly on the sensitive receptor cells.
The white part of the eye is called the sclera. It is continuous with the cornea on the anterior surface of the eyeball. The choroid is a membrane that lines the insides of the sclera and contains many blood vessels which supply nutrients to the eye.
Around the pupil there is a colourful circle called the iris. Circular and radial iris muscles contract when they react to the amount of passing light. The ciliary body on each side of the lens contains ciliary muscles which can adjust the shape and thickness of the lens. This mechanism is called accommodation and it helps refract the light. The ciliary body also produces a fluid called aqueous humour which fills the anterior chamber of the eyeball. The fluid in the vitreous chamber is called vitreous humour.
The retina is the sensitive nerve layer of the eye. It is made up of sensitive receptor cells: rods and cones. Light energy causes a chemical change in the rods and cones and starts nerve impulses which then travel to the brain through the optic nerve. The place in the eye where the optic nerve meets the retina is called the optic disc. A yellow spot in the center of the retina is called macula lutea. In the middle of it, there is a pit called fovea centralis which is the place of the sharpest vision. Reversely, the blind spot is the place of no vision. The optic nerve fibres cross. This is called the optic chiasma. The nerves then form optic tracts that synapse in the thalamus and end in the right and left visual regions of the cerebral cortex.
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sight
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zrak
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taste buds
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chuťové pohárky
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impaired
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poškozený
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blind
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slepý
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blur
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zamlžit
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loss
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ztráta
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clarity
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ostrost
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cataract
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šedý zákal
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pupil
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zornice
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conjunctiva
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spojivka
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cornea
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rohovka
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bend, refract
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ohýbat
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focus
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zaostřit
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sclera
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skléra
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continuous
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spojitý
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iris
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duhovka
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shape
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tvar
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thickness
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tloušťka
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lens
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čočka (POZOR! Jednotné číslo!)
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accommodation
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zaostřování, akomodace
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chamber
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komora
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retina
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sítnice
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rods and cones
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tyčinky a čípky
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pit
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jamka
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Hearing does not happen in the earlobe itself. The ear can be divided in three parts: outer ear, middle ear, and inner ear. The sound waves are received by the outer ear and transmitted by receptor cells to nerve fibres which lead to the auditory region of the brain in the cerebral cortex. In the outer ear there is the auricle or pinna, and the external auditory canal lined with glands that secrete yellowish substance called cerumen.
Sound waves then strike the tympanic membrane or eardrum between the outer and middle ear. That is formed by three ossicles: the malleus, the incus and the stapes. The canal which leads from the middle ear to the pharynx is called the eustachian tube. It prevents damage to the eardrum and shock to the middle and inner ears. It opens when you swallow thus balancing the atmospheric and middle ear pressures. Sound vibrations reach the inner ear called the labyrinth. Its bony part, the cochlea, contains the organ of Corti. Cilia in this organ receive vibrations and relay the waves to auditory nerve fibres which end in the auditory center of the cerebral cortex.
People who lose hearing are deaf, other problems might be ringing or buzzing (tinnitus).
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earlobe
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boltec ucha
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auditory
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sluchový
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yellowish
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nažloutlý
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strike
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udeřit
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eardrum
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bubínek
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ossicle
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kůstka
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malleus
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kladívko
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incus
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kovadlinka
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stapes
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třmínek
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swallow
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polykat
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cochlea
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hlemýžď
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relay
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předat informaci
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deaf
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hluchý
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numbness
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necitlivost
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tingling
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brnění
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pins and needles
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jehličky
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