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77 Cards in this Set
- Front
- Back
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Define Gustation
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The process by which chemicals dissolved in saliva confer the sensation of taste.
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What are the five classes of gustation?
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Sweet, salty, sour, bitter and umami
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What exactly are taste buds?
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These are groups of cells found in some types of the mucosal papillae.
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Cells which make up taste buds will degenerate and die after how much time?
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About one week.
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The taste buds that die will be replaced by the division of what type or group of cells?
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Basal cells.
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Which cranial nerves are responsible for for gustation?
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Cranial nerves V11, 1X and X.
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When chemoreceptors bind to the chemical they recognize they change structurally. True/False
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True.
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This organ of smell is located in the roof of the nasal cavity. What is it?
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The olfactory organ.
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Olfactory cells are considered unipolar neurons. is this a true statement?
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No. They are bipolar neurons.
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How many odorant receptors are there?
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There are hundreds of odorant receptors.
However, each neuron expresses one, or several odorant receptors. |
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What is the function of eyelashes?
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Aside from protection, they are sensitive receptors for touch. Reflex eyelid closure is automatic when a touch stimulus is unexpected.
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What are the conjuntiva?
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They are thin delicate mucus membranes that are somewhat transparant. They line the eyelids as well as the frontal or anterior surface of the eyeball. They prevent corneal desiccation.
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How do tears anatomically enter the eye?
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They enter from a superior-lateral angle. They are drained via ducts at the medial angle or corner of the eye known as the medial canthus.
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What is contained within tear secretions?
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mucus, lysozyme and antibodies(mostly IgA).
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How many extrinsic eye muscles are there?
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There are four rectus muscles. They may direct the eyes up, down, left or right.
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What other extrinsic eye muscles exist?
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There are two oblique eye muscles. Their function is to keep the eye from spinning or twisting. There is a superior and inferior group.
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Within the most posterior region of the eye, the optic nerve is covered by what structure?
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The fibrous tunic.
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The fibrous tunic is continuous with which meningeal layer?
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The dura mater.
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regarding the wall of the eyeball, what makes up the middle layer?
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The vascular tunic, or uvea.
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Which structure actually forms the iris?
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The vascular tunic.
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Where is the choroid found?
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It is found behind or posterior to the ciliary body.
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What is the choroid?
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It is a darkened membrane that has blood vessels that nourish the eye tunics.
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This is the innermost layer of the eye. What is it?
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It is the retina, or sensory tunic.
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The cells of the exterior layer of the retina act as phagocytes and store vitamin A. True/False
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True.
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The outer layer of the retina is pigmented for what purpose?
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This prevents light from being reflected from the posterior region of the eye.
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The inner layer of the retina contains what kind of cells?
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Photoreceptor cells.
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Is the lens a flexible structure?
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Yes. Its shape may be altered for focusing on objects that are distant or nearby.
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Where are crystallin proteins found?
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These are special proteins that make up the lens.
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The anterior cavity of the eye if filled with vitreous fluid. True/False
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False. It is filled with acqueous humor.
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What structure separates the posterior and anterior chambers of the eye?
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The lens.
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Does the iris separate any significant regions of the eye?
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Yes. It separates the anterior and posterior chambers of the anterior cavity of the eye.
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Before exiting the eye, axons of the retinal ganglion cells course along the surface of the retina as which nerve?
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The optic nerve
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What is the optic disc?
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This is the area of the retina where axons that belong to the retinal ganglion cells leave the eye.
This is also called the blindspot. |
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Where are photoreceptor cells located within the optic disc?
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There are no photoreceptor cells in this region of the eye.
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What is the function of the cornea?
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The cornea is responsible for the bending of light which is why an image is able to form on the retina.
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What is the shape of the lens in an eye that is considered decontracted or relaxed?
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It is stretched by ocular ligaments.
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Which specific structure must be contracted that will result in diminished tension of the lens? The ciliary body.
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The ciliary body.
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What happens chemically when the photopigment residue is struck by light?
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It is broken down into retinal and opsin.
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What effect does opsin have when it activates a second messenger system?
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It closes sodium channels in the photoreceptor cells.
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Where is rhodopsin found?
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It is found in rods. it is a photopigment.
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What are the two types of photoreceptor cells?
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Rods and Cones.
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Why is the clarity of vision with rods lower with respect of vision with cones?
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This is because several rods are required to activate each ganglion.
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Which exact region of the eye has the highest acuity and why?
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It is the macula lutea and fovea centralis. These regions have the most cones. There are few rods here.
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What is astigmatism?
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Astigmatism is an optical defect in which vision is blurred due to the inability of the optics of the eye to focus a point object into a sharp focused image on the retina. This may be due to an irregular or toric curvature of the cornea or lens.
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What is another term for nearsightedness?
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Myopia.
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What is hyperopia?
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It is farsightedness.
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What is a structural cause of farsightedness?
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The eye is somewhat shortened, and the lens cannot curve enough to focus on nearby objects.
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What is the clouding of the lens called?
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a cataract.
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What are some causes of cataracts?
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Aging,
Diabetes Smoking UV light |
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What is color blindness?
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It occurs as a result of lacking one or several specific types of cones. It is also known as Daltonism. Its cause is usually genetic in origin.
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Daltonism usually is from a deficiency or defect on the X chromosome. True/False
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True.
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When one enters a poorly lit room at first, why is vision usually poor?
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The rhodopsin in the the rods is strongly photobleached, and the cones are not yet sufficiently sensitive enough to detect the dim light.
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How doe sthe pupil respond when entering a dark room?
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It dilates in an attempt to capture any residual light.
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What are the three areas of the brain where optic nerve fibers travel to?
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Thalamus
Midbrain Hypothalmus |
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What is the purpose or function of optic nerve fibers when traveling to the midbrain?
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It is for eye movement and pupil dilation.
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What is the relationship of optic nerve fibers and the hypothalamus?
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Perception of time of day and possibly the regulation of the circadian rhythm.
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How is depth perception made possibe?
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This process is believed to occur in the thalmus. The thalamus separates signals from both eyes before forwarding the signals to the vision cortex.
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Which structure is considered a dividing boundary between the outer and middle ear?
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The tympanic membrane(eardrum).
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What is the function of the pharyngotympanic tube?
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It joins or connects the middle ear to the nasal pharynx.
Another function is so air pressure in the middle ear may equalize with the outside environment. |
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What are the bones or ossicles of the inner ear?
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The malleous
Incus stapes Transmit vibratory motion from the tympanic membrane to the oval window. |
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What is another term for the inner ear?
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The labyrinth
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What is the bony labyrinth?
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It is the section of the inner ear that forms from the temporal bone.
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What is the membranous labyrinth?
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It is the soft tissue portion of the inner ear.
It is surrounded with a fluid called perilymph, and is filled with endolymph. |
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Which part or region of the inner ear is responsible for equilibrium?
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The vestibule.
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What are the semicircular canals?
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Found within the inner ear, they sense and interpret rotation of the head.
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What is the snail shaped organ that is responsible for hearing called?
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The cochlea. More specifically, the Organ of Corti is the chief organ responsible for hearing.
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What results as a result of the ossicles moving or vibrating?
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Their movement is interpreted to motion of the perilymph fluid.
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What are stereocilia?
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When fibers of the basilar membrane move, the stereocilia or hair cells will stimulate the cochlear nerve.
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what are the two chambers of the vestibule?
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The utricle
Saccule |
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What are otoliths composed of?
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Calcium carbonate stones.
The weight or mass of the otoliths will augment the inertia of this region in order to permit to sense major changes in head rotation. |
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Where are ampullae found?
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The widened regions at the entrance to each semicircular canal are termed ampullae.
each semicircular canal houses a special receptor of equilibrium called the crista ampullaris. |
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What is the name of the soft ridge where the crista ampullaris have hair cells?
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The cupola.
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What is meant by conduction deafness/
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Disturbed or impaired sound conduction to or through the fluids of the inner ear.
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define tinnitis.
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Though it can have many causes, it is heard or sensed as a ringing, swishing or clicking in the absence of auditory stimuli..
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When is vision considered fully matured?
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between 5-7 years of age.
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What is macula degeneration?
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It is usually associated with age, and occurs as a result of damage to the macula lutea. There is a wet and dry form.
Commonly, only peripheral vision remains. |
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Are the ossicles prone to osteosclerosis?
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Yes. This may occur as a result of inflammation, infection and normal aging. Conduction deafness usually results..
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