Receptors

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  • Created by: Thabisa18
  • Created on: 12-05-23 11:01
Sclera
Protects the inner structures of the eye along with maintaining its shape.
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Cornea
The transparent cornea allows light to pass through and refracts (bends) the incoming light to form an image on the retina.
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Choroid
The pigments of the choroid function in absorbing light in order to prevent reflection of the light. The blood vessels contained in the choroid are responsible for supplying nutrients and oxygen to the cells of the retina.
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Ciliary body
The ciliary body contains the ciliary muscles which act to alter the tension on the suspensory ligaments, by contracting or relaxing.
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Suspensory ligaments
The suspensory ligaments attach to the ciliary body and form a support for the lens.
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Iris
The iris is the coloured portion of the eye. It contains an opening at its centre, called the pupil. The iris contains two types of muscles, which act to control the size of the pupil which itself lets light into your eye.
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Retina
The retina is the inner layer of the eye which contains the rods and cones (photoreceptors) that are sensitive to light.
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Yellow spot/Macula
The yellow spot or macula is a small indentation at the back of the eyeball that contains the most cones.
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Blind spot
The blind spot is a small area found on the retina of the eye, below the yellow spot. It contains no rods or cones (photoreceptors) and hence does not provide any vision.
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Lens
The lens is a transparent, elastic, biconvex structure found behind the pupil of the iris. It is held in place by the suspensory ligaments.
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Aqueous humour
The aqueous humour is a watery fluid that is found in the space between the cornea and the lens.
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Vitreous humour
The vitreous humour is a jelly-like substance that is found behind the lens.
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What is the function of the sclera?
The sclera has the function of protecting the inner structures of the eye along with maintaining its shape.
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What is the function of the cornea?
The transparent cornea carries the function of allowing light to pass through and refracts (bends) the incoming light to form an image on the retina.
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What is the function of the choroid?
The pigments of the choroid function in absorbing light in order to prevent reflection of the light. The blood vessels contained in the choroid are responsible for supplying nutrients and oxygen to the cells of the retina.
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What is the function of the ciliary body?
The ciliary body contains the ciliary muscles which act to alter the tension on the suspensory ligaments, by contracting or relaxing.
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What is the function of the suspensory ligaments?
The suspensory ligaments are responsible for holding the lens in position, during the process of accommodation. Additionally, the tension on the suspensory ligaments changes in order to alter the shape of the lens.
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What is the function of the iris?
The iris controls the amount of light that enters the eye, through the pupillary mechanism.
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What is the function of the retina?
The retina contains the photoreceptors that are sensitive to light. The rods respond to low-intensity light and provide both night vision and peripheral vision. The cones, on the other hand, respond to bright light and provide sharp, vivid colour vision.
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What is the function of the yellow spot/macula?
Due to the fact that it contains the most cones, the yellow spot or macula is the area of clearest vision.
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What is the function of the blind spot?
It is responsible for the inner parts of the eye being supplied with oxygen and nutrients and is also responsible for impulses being transmitted to the cerebrum for interpretation.
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What is the function of the lens?
The lens allows the eye to focus on both near and distant objects, by changing shape. Due to its transparency, it also allows light to pass through.
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What is the function of the aqueous humour?
The aqueous humour is responsible for maintaining the shape of the cornea. Additionally, it plays a small role in the refraction (bending) of the incoming light.
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What is the function of the vitreous humour?
The vitreous humour maintains the (round) shape of the eyeball. Additionally and like the aqueous humour, it plays a small role in the refraction (bending) of the incoming light.
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Binocular vision
Binocular vision is the ability to focus on a single object, using both eyes. Each eye sees a separate image. Our brains then put the two images together, giving us a 3D view of the world around us.
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Accommodation
Accommodation is the process where the lens of the eye changes its shape, to allow for a clear image to fall on the retina, whether the object is near or distant.
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Pupillary reflex (pupillary mechanism)
The pupillary reflex or pupillary mechanism is the process by which the diameter of the pupil is altered to regulate the amount of light entering the eye.
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Long-sightedness
Long-sightedness is a visual defect that occurs when a person has the ability to see objects that are far away (distant objects) but is unable to see objects that are close by (nearby objects) clearly.
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Nature of the defect(long-sightedness)
When an individual suffering from long-sightedness is looking at a nearby object, the light rays focus behind the retina, causing blurred vision.
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Cause of the defect(long-sightedness)
-The eyeball being too short/rounded
-The cornea not being curved enough for the length of the eyeball
-The inability of the lens to become more convex
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Possible treatment(long-sightedness)
Wearing glasses with convex lenses (this will help by focusing the light rays inwards slightly first before the light rays reach the lens so that the lens can then provide the final refraction that focuses the light on the retina).
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Short-sightedness
Short-sightedness is a visual defect that occurs when a person has the ability to see objects that are close by (nearby objects) but cannot see objects that are far away (distant objects) clearly.
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Nature of the defect(short-sightedness)
When an individual suffering from short-sightedness is looking at a distant object, the light rays focus in front of the retina, causing blurred vision.
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Cause of the defect(Short-sightedness)
-The eyeball being too long
-The cornea being too curved for the length of the eyeball
-The inability of the lens to become less convex
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Possible treatment(short-sightedness)
Wearing glasses with concave lenses (helps by essentially focusing the light rays outwards slightly first before the light rays reach the lens, so that the lens can then provide the correct amount of refraction that focuses the light on the retina)
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Astigmatism
Astigmatism is a visual defect that occurs when the cornea or the lens of the eye is not equally rounded in all directions as it normally would be.
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Nature of the defect(Astigmatism)
When an individual has an astigmatic eye, the light that enters the eye is not focused evenly on the retina. This can lead to blurred vision, headache's and squinting of the eyes (in an attempt to focus the light more evenly and provide clearer vision).
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Cause of the defect(Astigmatism)
The cornea or the lens of the eye not being equally rounded in all directions.
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Possible treatment(Astigmatism)
-Wearing glasses with prescription lenses
-Wearing contact lenses
-Laser therapy
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Cataracts
Cataracts is a visual defect that occurs when the clear transparent lens of the eye becomes cloudy, resulting in blurred vision.
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Nature of the defect(cataracts)
When an individual has a cataract, light is prevented from entering the eye, resulting in blurred vision. The cataract develops slowly and increases in size over time.
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Cause of the defect(Cataracts)
-Ageing or injury changing the tissue that makes up the eye's lens
-Some inherited genetic disorders that cause other health problems can increases the risk of cataracts.
-past eye surgeries or medical conditions, such as diabetes.
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Possible treatment(Cataracts)
-Early on, glasses may be used
-As the cataract develops (grows in size), surgery may be required. In this case, the lens is removed and a synthetic lens is inserted.
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What is responsible for balance in the human ear?
The cristae in the semicircular canals and the maculae in the sacculus and utriculus.
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What stimulates the cristae in the semicircular canals?
Changes in the direction and speed of movement.
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What stimulates the maculae in the sacculus and utriculus?
Changes in the position of the head.
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What happens when the cristae and maculae are stimulated?
They convert the stimuli received into nerve impulses.
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Where are the nerve impulses transported along?
The auditory nerve.
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Where do the nerve impulses go to be interpreted?
The cerebellum.
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What does the cerebellum do after interpreting the nerve impulses?
It sends impulses to the muscles to restore balance.
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What are the causes of a hearing defect in the middle ear?
Middle ear infection and excess fluid in the middle ear caused by pathogen infection.
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What are the treatment options for a hearing defect in the middle ear?
Inserting grommets and antibiotics.
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What are the causes of deafness?
Injury to parts of the ear, nerves, or parts of the brain responsible for hearing, hardened wax, and hardening of ear tissues such as ossicles.
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What are the treatment options for deafness?
Hearing aids and cochlear implants.
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What is the role of the pinna?
The pinna directs sound waves to the eardrum.
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What is the role of the tympanum (eardrum)?
The tympanum transmits sound waves to the middle ear.
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What is the role of the ossicles?
The ossicles transmit vibrations from the eardrum to the inner ear.
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What is the role of the oval window?
The oval window vibrates and causes pressure waves in the inner ear.
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What is the role of the cochlea?
The cochlea receives vibrations from the oval window, stimulating sensory cells in the organ of Corti, generating nerve impulses.
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What is the role of the auditory nerve?
The auditory nerve transmits nerve impulses from the cochlea to the cerebrum to be interpreted.
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What is the role of the Eustachian tube?
The Eustachian tube equalizes pressure on either side of the eardrum.
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What is the role of the oval window?
The oval window transmits sound waves to the inner ear.
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What is the role of the semicircular canals?
The semicircular canals are responsible for the balance of the body.
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Other cards in this set

Card 2

Front

The transparent cornea allows light to pass through and refracts (bends) the incoming light to form an image on the retina.

Back

Cornea

Card 3

Front

The pigments of the choroid function in absorbing light in order to prevent reflection of the light. The blood vessels contained in the choroid are responsible for supplying nutrients and oxygen to the cells of the retina.

Back

Preview of the back of card 3

Card 4

Front

The ciliary body contains the ciliary muscles which act to alter the tension on the suspensory ligaments, by contracting or relaxing.

Back

Preview of the back of card 4

Card 5

Front

The suspensory ligaments attach to the ciliary body and form a support for the lens.

Back

Preview of the back of card 5
View more cards

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