Final Pt. 2 Flashcards
Chemoreceptors respond to…
chemicals in aqueous solutions (saliva, nasal mucuos)
What are some features of olfactory cells?
replaced every 4-8 weeks, dendrite towards mucus (captures airborne odorants, few molecules activate cell)
What system do olefactory receptors use?
2nd messanger system to trigger ligand channels with Na, Ca
Where do olefactory APs synapse?
AP carried to olefactory bulbs, synapse on mitral cell
3 steps of olefactory transmission?
- Axons travel past cribiform plate/ ethmoid bone to reach olefactory bulb
- synpase w/ mitral cell to form olefcatory tract
- olefactory tract goes to limbic system and olefactory cortex
Sense of smell does not:
Pass through thalamus
In order to taste…
Much touch hairs on gustatory neurons
Binding of chemical depolarises membrane (generator potential to brainstem)
Taste is a…
complex sensory reception
What is a taisant?
odorant, binds to specialized receptors on gustatory hairs open graded potential, activates afferent fibers
what 2 facial nerves aide in taste?
Facial nerve (XII) and glossopharyngeal (IX)
What 4 cells make taste cells?
epithelial cells, gustatory cells (sensory taste) basal cells (stem cells), can sense touch and thermal
supporting cells (insulating receptor)
What do the microvilli is gustatory cells do?
extend through taste pore into salivia to detect chemicals
5 tastes correspond with what ions?
sweet- sugar, alcohol, amino acids (guslducin)
salt- metal ions (Na)
sour- hydrogen ions
bitter- alkaloids (nicotine, quintinko)
Umami- glutamate (amino acid)
Pathway of taste through facial nerves
facial and glossopharyngeal nerve take impulse to solidary nucleus of the medulla- thalamus- gustatory cortex- hypothalamus and limbic system
What influences taste?
80% smell, thermoreceptors and mechanoreceptors also influence taste
What is conjunctivia
transparent membrane that lines eyelid as palabrea conjuctivia and covers whites of eyes as occular conjuctivia
What is conjuctivitis
Pink eye
What is the cilliary body?
fine focus, less than 20 ft
as muscles relax, lens gets rounder
connected to cillilary zonule (which inserts into lens)
Label eye
LABEL
What is the palebrae?
eyelids, palpebral fissure seperates eyelids
levator palpabrae superioris (elevates) , tarsal plates supports eyelid
What part of eye is important for focus?
cornea shape is important for focus, not lens which looses elasticity with age
Scleral venus sinus
point of transistion between white and iris
Lens moves what way for vision?
flattens for distant, bulges for close
Constrictor/ dialtor pupillae
Constrict/ dialate pupil (under PNS)
6 steps in production of tears
1- lacrimal gland produces secretions
2- tears enter conjuctivial sac
3- tears flow upper left to lower right
4- tears enter lacrimal cannuli
5- drain into lacrimal sac
6- Empty via nasal-lacrimal duct
What is the optic disc
lots of ganglion cells, exit eye and go to thalamus
blindspot
No light absorption due to high density of myleinated axons and no photoreceptors
what gives blood supply to eye?
central artery and vein of retina
emmertropic, myopic, hyperopic?
normal, nearsighted (long eyeball), hyperopic (far sighted (short eyeball)
what are ganglion cell axons?
run along inner surface of retina and leave as optic @ optic disc
What is the Macula lutea?
High density of photoreceptors, center. of fovea centrialis (highest concentration of cones)
max light density area
Rod vs cone cell:?
rod- 1 cell for one pigment (black/ white)
cone- 3 different cells for different pigments (red/ green/ blue)
What is rhodospin?
photosensitive protein in retina that bends of cause confromational change
How does rhodopsin work?
more cis retinal (bent) in produced in the dark
in light retinol is bleached into all- transform (straight)
- this dissaction causes g protein reaction via oxidation
Dark vs light eye channels
Dark Light
Depolarize Hyperpolarize
Ca channels open ca channels closed
IPSP, No Nt No NT, No ISPS
No ESPS NT released
No AP ESPS in ganglion
AP
