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53 Cards in this Set
- Front
- Back
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What are the three locations of special senses? |
Exteroceptors (surface of the body), visceroceptors (internal organs), Proprioceptors (joints, muscles, tendons) |
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How are mechanoreceptors activated? |
Activated by deformation/change in position of receptor in some way (touch) |
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How are Chemoreceptors activated? |
by change in concentration or amount of chemicals? |
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How are thermoreceptors activated? |
by change in the temperature |
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how are nociceptors activated? |
by intense stimuli resulting in tissue damage (chemical, pressure, heat) |
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how are photoreceptors activated? |
by light stimuli (only in the eyes) |
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What are chemoreceptors in relation to the sense of smell? |
they are olfactory receptors that detect chemicals in solution |
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Where are the nerve endings(cilia) of olfactory receptor neurons? |
In the epithelium of roof of the nasal cavity |
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When are receptor potentials generated in olfactory receptor neurons? |
When chemicals dissolved in mucus covering olfactory epithelium bind to odor receptors |
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How does the message of a smell reach the brain? |
Sum of receptor potentials= action potential. AP propagated through to olfactory nerves then olfactory tract into olfactory centre in temporal love for interpretation, integration and memory. |
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What are the 7 primary qualities of smell? |
Peppermint, musk, floral, ethereal, pungent, putrid and camphoraceous. |
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What other functions is smell linked with? |
memory (limbic system) and linked to taste through common pathways |
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how many chemoreceptors are on each taste bud and what are they called? |
125, gustatory cells, -small specialised receptor cells on each taste bud. |
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What are the chemicals called that dissolve in saliva and bind to receptors called? |
Tastants |
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What are the 5 primary taste sensations? |
salty, sour, bitter, sweet, umami |
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How is a 'saltiness' action potential generated? |
NaCl receptor in the mouth- an ion channel in the receptor allows Na+ to enter the cell and action potential is generated. |
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How is a 'sourness' action potential generated? |
simple ion channel allowing H+ ions into the cell |
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How is a 'bitterness' action potential generated? |
bitter compounds act through G-protein- coupled receptors (GPCRs) |
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How is a 'sweetness' action potential generated? |
sugars act through G protein-coupled receptors |
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How is a 'umami' action potential generated? |
involves G protein-coupled receptors, responds to MSG |
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What part of the tongue is connected to the facial nerve VII? |
anterior 2/3 of tongue |
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What part of the tongue is connected to the glossopharyngeal nerve IX? |
posterior 1/3 of tonuge |
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What part of the tongue/mouth is connected to the vagal nerve X? |
pharynx |
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Where do the three cranial nerves VII, IX and X carry nerve impulses to? |
The medulla oblongata |
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After the medulla oblongata, where do taste senses go? |
the thalamus, and then into the taste centre of the cerebral cortex - the parietal lobe. |
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What are the two functions of the ear? |
hearing and balance |
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What are the three major areas of the ear? |
external ear, middle ear and inner ear |
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Describe the external ear? |
pinna (auricle) -visible portion- fibroelastic cartilage. External auditory meatus (ear canal) -about 3cm long- cartilage and temporal bone. Modified sweat glands (ceruminous) secrete cerumen. Tympanic membrane (eardrum) - terminal wall of external ear and separates external from middle. |
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Describe the middle ear |
tiny cavity within temporal bone of skull. contains 3 auditory ossicles: malleus (hammer shape), incus (anvil shape) and stapes (stirrup shape. It goes from tympanic membrane to malleus to incus to stapes which is then connected to oval window of inner ear. Eustachian tube- extends from the middle ear to nasopharynx. Equal pressurization between external and middle ear. |
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Describe the inner ear (the labyrinth) |
Includes the choclea (hearing function), the vestibule (involved in static balance/equilibrium) and the semicircular canals (involved in dynamic balance/equilibrium). |
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Describe the choclea and its function |
-contains organ of courti- hearing sense organ which consists of supporting cells and hair cells. -sound waves are heard through fluid movement in choclea ducts which bends the cilia on the hair cell which results in mechanical deformation of hair cell and then opens and closes ion channels generated graded potentials. Generation of AP and transmission to attached cochlea nerve (cranial nerve VIII) |
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What is presbycusis? |
hearing loss due to old age. Damage to hair cells in organ of corti due to its atrophy. Is also associated with degeneration of CN VIII and loss of receptors. There is similar loss after chronic exposure to loud noises. |
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What is Meniere's disease? |
Excessive endolymph accumulation causing pressure that disrupts balance and hearing resulting in vertigo, tinnitus, nausea and/or deafness. |
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What is the function of the vestibule? |
It detects the position of head in relation to gravity or acceleration/deceleration of the body when motionless -moving car. |
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What is the function of the semicircular canals? |
activated when head or body suddenly moves or rotates which helps maintain balance. |
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What are the three layers of the eye? |
fibrous (sclera, cornea), vascular (choroid, ciliary body and iris), inner layer (retina, optic nerve and retinal blood vessels) |
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What does intraocular pressure prevent? |
the eyeballs from collapsing |
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Where is vitreous humor located? |
vitreous humor fills posterior cavity posterior to lens |
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Where is aqueous humor located? |
fills anterior cavity in front of lens and small space behind iris. Is formed by blood in ciliary body capillaries and drains into canal of Schlemm (into veins). |
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What does change to rate of production to rate of drainage lead to? |
increased intraocular pressure- glaucoma- if untreated can lead to damage and blindness. |
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Where is the retina located and what does it include? |
the innermost coat- thickest at rear. Contains the optic disc (blind spot where optic nerve leaves the retina), three types of neurons (photoreceptors, bipolar and ganglion) and several small arteries and veins |
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what are the two types of photoreceptors? |
rods and cones |
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What do photoreceptors do? |
conduct impulses to bipolar neutrons then onto ganglion neutrons before transmitting impulse via the optic nerve (cranial nerve II) then to the occipital lobe of the brain. |
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What is refraction? |
when light rays are deflected (bent) by the cornea, aqueous and vitreous humor and lens to focus light onto the retina |
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What is myopia? |
near sightedness (due to imperfection of refraction) |
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What is Hyperopia? |
farsightedness (dues to imperfection of refraction) |
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What is astigmatism? |
irregular curvature of the cornea |
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What is cataracts? |
cloudy area within the lens due to age related degeneration |
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What is retinal detachment (retinoschisis)? |
fluid accumulation that separates retina from underlying tissue |
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What is accommodation of the lens? |
increased curvature of the lens (bulges) to achieve refraction |
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What is presbyopia? |
occurs with ageing as lens losses elasticity, inability to bulge and accommodate for near vision thus old people tend to become far sighted. |
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What is constriction of the pupil? |
muscles of the iris contract to reduce the size of the pupil and the amount of interference from peripheral visual rays. |
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What is convergence of the two eyes? |
movement of the two eyeballs inwards to facilitate projection of light onto the same part of each retina; provides for binocular vision otherwise diplopia develops (seeing double) |
