OLFACT
ION
ION
What is olfaction? What structures are involed?
Sense of smell.
Neurons, the olfactory organs, stimuli
What are the 4 primary taste sensations and the 2 additional taste sensations?
1. Sweet
2. Salty
3. Sour
4. Bitter
- Umami; amino acid glutamate
- Water receptors
Where are the two palpebral fissures connected?
Medical(canthus) and lateral(canthus) angles
What is accomodation?
Automatic adjustment of the eye for clear vision.
Rounder - near vision
Flatter - far
What are the 3 types of cones?
1. blue
2. green
3. red
overlap to produce color vision
Why might an elderly person have trouble smelling a very fagrant candle?
Olfactory neurons decrease with age, so higher concentrations of an odorant are needed to activate olfactory neurons.
What are the 4 lingual papillae? Where is each located along the tongue?
1. Filiform - anterior 2/3rds parallel to midline groove, no tastebuds, friction
2. Fungiform - scattered, concentration of tip/sides, 5 tastbuds each
3. Vallate - V shap line on posterior tongue margin, 100 taste buds each
4. Foliate - lateral margins
What glands are found on the inner margin of the eyelid/eyelashes, and what is their function?
What is visual acuity?
How well can a person see at a certain distance in feet by someone with normal visions. 20/20
20/15 - at 20ft, person can see what a normal person can see at 15 ft
what the 6 steps in the process of bleaching?
1. Light is absorbed and retinal changes activate opsin
2. Sodium ion permeability changes and so the rate of neurotransmitter releases changes
3. changes in bipolar cell occur by ganglion cells - indicates what potion of the retina is photon stimulated
4. photon is absorbed, rhodopsin breaks down into retinal/opsin
5. retinal goes back to original shape - requires ATP
6. Retinal converted, can combine with opsin, rhodopsin ready
What is the name of the adaptive function that desensitizes your sense of smell is exposed to a certain smell for long consecutive periods of time?
Central adaptation.
If you have dry mouth, why might you have trouble tasting food?
Gustatory epithelial cells can only detect molecules/ions that are dissolved in a solution.
What structure is involved in the production of "eye boogers"?
What is a scotoma?
Abnormal blind spot, permanent
What vitamin can treat night blindness?
A
Trace the olfactory pathway from the momemt a stimuli reaches the epithelium to the moment it reaches the limbic system.
1. Chemical stimuli
2. Olfactory epithelium
3. Olfactory bulb
4. olfactory tract
5. CNS ( olfactory cortex > hypothalamus > limbic sysyem )
What cranial nerves are involved in gustatory pathways?
VII - facial
IX - glossopharyngeal
X - vagus
V - TRIGEMAL
What is a chalazion?
Infection of the tarsal gland resulting in a cyst.
A sty happens when a sebaceous gland associated with an eyelash cause localized/painful swelling.
What is myopia?
What is the adaptation mechanism that allows your eyes to adjust to different types of room/environment lighting?
Dark-adapted state and light adapted state
Explain what happens in each of the 3 steps that culminate in a action potential in olfaction.
1. Odorants bind to receptos, adenylate cyclase converts ATP to cAMP
2. Sodium ion channels open, depolarization begins
3. Depolarization triggers potential, nerve impulse (smell) send to CNS (afferent)
Michael hates vegetables such as Brussel sprouts and califlower, because they taste bitter. To what compund is he genetically taste sensitive to?
PTC: phenyl-thio-carbamide
What causes glaucoma?
Scleral venous sinus - blocked
Aqueous humor cannot drain - increased pressure > distorts vision
closed and open angle
What is heyperopia?
Farsightedness. Not enough retraction. Image focused behind the retina.
Describe the steps in the reception and transduction of sound energy.
1. sound waves arrive at tympanic membrane
2. tympanic membranes moves and displaces auditory ossicles
3. movement at stapes and oval window produce waves in perilymph
4. pressure waves distor basilar membrane on path to round window
5. basilar mebrane vibration causes hair cells to vibrate against tectorial membrane
6. Region information and stimulation intensity relayed to CNS over cochlear nerve