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61 Cards in this Set
- Front
- Back
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What do the special senses include? |
Taste buds Olfactory epithelium Eyes Ears Vestibular apparatus |
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How do the special senses work? |
They transduce a stimulus from one form (chemical,light,vibration,movement) into nerve impulses (Action potentials) |
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What are the chemical senses? |
Taste and smell (olfaction) |
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How do chemical senses work? |
Their chemo-receptors respond to chemicals in aqueous solutions (chemicals dissolve) |
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Explain the physiology of smell |
-Dissolved odorants bind to receptor proteins in the olfactory cilium membranes -A G protein mechanism is activated, which produces cAMP as a second messenger
-cAMP opens NA+ and Ca+ channels, causing EPSP depolarization of the receptor membrane that can reach threshold through summation to trigger an AP |
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How many different smells can we make out? |
2000-10,000 |
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What happens after we smell an odor? |
-Olfactory cells synapse with mitral cells in glomeruli of the olfactory bulbs -Mitral cells amplify, refine,and relay signals along the olfactory tracts to the olfactory cortex, then to the hypothalamus,amygdala,and limbic system (for emotional response to odors) |
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How are we able to adapt to bad smells |
Signals from the olfactory receptor cells simultaneously receive IPSP'S (GABA) so that only highly excitatory olfactory EPSP's generate AP |
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Which division of the ANS do dangerous smells initiate? |
The sympathetic nervous system |
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Which division of the ANS do good food smells initiate? |
The parasympathetic, which increases salivation and GI secretions |
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What are the 5 different tastes? |
Sweet, salty, sour, butter, and umami |
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Is spicy hot a taste? |
No, it is a pain |
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What is the most sensitive taste? |
Bitter |
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In order to be tasted, a chemical _________ |
-Must be dissolved in saliva, and contact the gustatory hairs |
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Which two tastes bind directly to the chemically gated channel causing sodium channels to open? |
Salty and sour |
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Which three tastes use G proteins that require a second messenger? |
Sweet, bitter, and umami |
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Which cranial nerves carry impulses from taste buds to the solitary nucleus of the medulla? |
Facial 7 and glossopharyngeal 9 |
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How does the gustatory work with taste signals? |
Taste signals initiate parasympathetic stimulation which causes salivation and secretion of gastric juices |
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Taste is ___% smell |
80 |
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70% of all sensory nerves are in the ____ |
Eye |
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Nearly half of the ________ ________ is involved in processing visual information |
Cerebral cortex |
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Describe our lens |
Bioconvex, transparent, flexible, elastic, and avascular |
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Explain cataracts |
(Clouding of the lens) Occurs as a consequence of aging, diabetes mellitus, heavy smoking, increases free radical exposure, and exposure to intense sunlight |
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Explain Myopia (Nearsightedness) |
Focal point is in front of the retina (in a longer than normal eyeball) -Difficulty seeing distant objects -Corrected with a concave lens -Lasik corrects by making the cornea less convex |
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Explain Hyperopia (Farsightedness)- |
Focal point is behind the retina (in a shorter than normal eyeball)-Difficulty seeing close objects-Corrected with a convex lens (Shortens focal distance)
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Explain Astigmatism |
-caused by unequal curvatures in different parts of the cornea or lens -Corrected with cylindrical round lenses, corneal implants, or laser procedures |
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Explain accommodation in regards to close vision |
Changing the lens shape by ciliary muscles to increase refractory power |
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Explain constriction in regards to close vision |
The accommodation pupillary reflex constricts the pupils to prevent the most divergent light rays from entering the eye |
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Explain convergence in regards to close vision |
Medial rotation of the eyeballs toward the object being viewed |
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What is presbyopia? |
Loss of accommodation over the age of 50 |
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Explain rods (eyes) |
-More numerous at peripheral region of retina, away from the macula lutea -Operate in dim light -Provide indistinct, fuzzy, non color peripheral vision |
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Explain cones (eye) |
-Found in the macula lutea; concentrated in the fovea centralis -operate in bright light -provide high-acuity color vision |
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Explain retinal (eye) |
-Light absorbing molecule that combines with one of four proteins (opsin) to form visual pigments -Synthesized from vitamin A |
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Explain color blindness |
Due to a congenital lack of one or more of the cone types |
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Explain night blindness |
Impairment or degeneration of rods usually due to vitamin A deficiency |
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What is sound? |
A pressure disturbance (alternating areas of high and low pressure) produced by a vibrating object |
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What is a sound wave? |
-Moves outward in all directions -Sound waves move only .2 miles/sec(delay between lightning and thunder) -Is illustrated as an S-shaped curve or sine wave |
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What is frequency in regard to sound? |
Refers to the number of waves in a given period of time |
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What is wavelength in regard to sound? |
Refers to the distance between consecutive peaks or troughs |
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What is amplitude in regards to sound? |
The difference in pressure between crests and trough |
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Explain the transmission of sound to the internal ear |
-Waves with frequencies below the threshold of hearing travel through the heliocotrema and scali tympani to the round window -Sounds in the hearing range go through the cochlear duct, vibrating the basilar membrane at a specific location, according to the frequency of the sound. |
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What happens when the stereolcilia bends? |
-Opens mechanically gated ion channels -Inward K+ and ca+ current causes a graded potential and the release of neurotransmitter glutamate |
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Explain conductive deafness |
Blocked sound conduction to the fluids of the internal ear |
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What is conductive hearing loss a result of? |
Impacted earwax, perforated eardrum, or otosclerosis of the ossicles |
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Explain sensorineural deafness |
Damage to the neural structures at any point from the cochlear hair cells to the auditory cortical cells |
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Explain tinnitus |
Ringing or clicking sound in the ears in the absence of auditory stimuli |
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What is the cause of tinnitus? |
Due to cochlear nerve degeneration, inflammation of middle or internal ears, side effects of aspirin |
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Explain meniere's syndrome |
Labyrinth disorder that affects the cochlear and the semicircular canals |
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What are some of the symptoms of meniere's syndrome? |
Causes vertigo, nausea, and vomiting and hearing loss |
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What does the vestibular apparatus consist of? |
The equilibrium receptors in the semicircular canals and vestibule |
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What do the vestibular receptors monitor? |
Static equilibrium (side to side) horizontal and vertical head movements |
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What do the semicircular canal receptors monitor? |
Dynamic equilibrium (rotational head movements) |
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_________ responds to linear acceleration forces, but not rotation |
Maculae |
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Which type of hairs in the maculae monitor side to side movement? |
Vertical hairs (utricle) |
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Which type of hairs in the maculae monitor vertical movement?
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Horizontal hairs (saccule) |
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Semicircular canals detect changes in _________ |
Rotation |
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Vestibule detects changes in _________ |
Head position |
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Explain nystagmus |
Eyes drift back to previous fixation point as we continue to rotate, then jump forward to new fixation point |
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Explain the cows acronym for nystagmus |
Cold Opposite Warm Same |
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What is motion sickness? |
A disconnect in visual vs vestibular inputs |
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What is the treatment for motion sickness |
Block the vestibular transmissions |
