Exam 4- Special Senses Flashcards
the 5 special senses
smell taste hearing sight equilibrium
which senses are not special?
touch and stretch
how do special senses differ from general senses?
special senses have complex sensory receptors
the 2 chemical senses
gustation (taste) and olfaction (smell)
sensory receptor for gustation
taste bud
where are taste buds located?
in mucous papillae of tongue
and on soft palate (roof of mouth), cheeks, pharynx, epiglottis
papillae
projections on tongue which contain taste buds
fungiform & circumvallate
roughly how many taste buds are on the human tongue?
10k
fungiform papillae
scattered all over the surface of tongue
circumvallate papillae
way in the back of the tongue, form a V
very large and lumpy
there are 7-12 on tongue
structural components of taste bud
gustatory cells supporting cells basal cells taste pore gustatory hair
gustatory cells
taste bud cells
supporting cells of taste bud and olfactory receptor cells
cells surrounding receptor cells, most numerous
support, protect, and nourish sensory receptor cell
basal cells of taste buds and olfactory cells
stem cells that can become sensory receptor cells or supporting cells
at base of sensory receptor cells and supporting cells
actively reproducing- divide and replace continuously
taste pore
opening in taste bud
contain gustatory hairs
gustatory hairs
membrane that interact with the chemical (where chemicals flood/bind)
comes out of taste pores
extension of plasma membrane of gustatory cells
basic taste sensations
sweet sour salty bitter umami
which chemicals promote intake of what you’re eating (make you want to eat more)
sweet (sugars and alcohols) and salty (metal ions)
which chemicals activate sweet taste receptors?
sugars and alcohols
which chemicals activate salty taste receptors?
metal ions
which chemicals activate sour taste receptors?
acids
which chemicals activate bitter taste receptors?
alkaloids (nicotine, caffeine), and non-alkaloids (aspirin, beer hopps)
which taste sensation is a preventative, protective response?
bitter
this taste reduces the desire to eat
bitter is often associated with nitrogenous compounds, which could be toxic
which chemicals activate umami taste receptors?
glutamate (an amino acid)
what flavor is umami
“cooked meat”
glutamate gives foods extra flavor
t/f taste receptors all have the same threshold of how much of the chemical has to bind before it gets an action potential
false!
different receptors have different thresholds
do taste bud receptors adapt rapidly or slowly?
rapidly
physiology of taste (process)
- chemical dissolves in saliva
- chemical binds to gustatory hairs
- gustatory cell membrane depolarizes
- generator potentials created
- action potential is sent to CNS through cranial nerves
- neurotransmitter released
what mechanism of depolarization is used for salty and sour?
channel-linked (direct)
what mechanism of depolarization is used for bitter, sweet, and umami?
G-protein linked (indirect)
where in the CNS are action potentials sent for taste?
first to solitary nucleus in medulla
then through thalamus to gustatory cortex
also to hypothalamus (this is limbic system –> causes emotional run to food)
3 functions of taste
trigger digestive reflex
gagging
vomiting
sympathetic responses to taste
gagging and vomiting
these are preservation reflexes
parasympathetic response to taste
trigger digestive reflex
salivate, stomach produces gastric juice, get active and ready to digest
we taste something –> we like it –> activates digestive system
where is olfactory epithelium located?
located in the mucosa at roof of nasal cavity
structural components of olfactory receptor
olfactory receptor cells supporting cells basal cells olfactory cilia filaments of olfactory nerve
smell receptor cells
olfactory receptor cells
olfactory cilia
part that actually interacts with the chemical
hairlike extensions off olfactory receptor cells
on dendritic end of receptor cells (synapse with olfactory nerve)
embedded within mucosa
specific to certain chemicals
Olfactory receptor cells synapse with________ a the cribriform plate
filaments of the olfactory nerve
physiology of smell (process)
- gaseous molecules enter nasal cavity
- dissolves in epithelial mucus
- dissolved chemicals bind to receptor molecules on olfactory cilia
- receptor potential generated
- action potential transferred through filaments
- synapse with olfactory bulbs at glomeruli
- action potential sent to CNS via olfactory tracts
t/f olfactory receptors are off until a chemical turns them on
true
CNS destinations for smell
first to thalamus
thalamus –> olfactory cortex
hypothalamus –> amygdala and limbic system
what happens in olfactory cortex
interpretation and identification of smell
what happens when smell goes to amygdala and limbic system
elicits emotional response to odors
t/f concentration of scent chemical in the air has to be very high to elicit an emotional response
false! it can be quite minute and still elicit emotion
think aromatherapy
functions of smell
sympathetic activity
parasympathetic activity
sneezing
choking
preventive activity functions of smell
sneezing and choking
sympathetic activity functions of smell
we smell things that put us in attack/defense mode
we tend to gravitate toward the smell
pheremones
scents that elicit sexual arousal
parasympathetic activity function of smell
when you smell a good thing, digestion may begin
stomach starts churning, start salivating, etc
you’re walking down your street and all of a sudden catch a whiff of char-broiled burgers coming from your neighbors house. your stomach starts to churn and you start to salivate. is this a sympathetic or parasympathetic function of smell?
parasympathetic
it is related to digestion
sensory receptor of vision
eyeball
70% of all sensory receptors are in which structure?
eyes
accessory eye structures
eyebrows eyelids eyelashes conjunctiva lacrimal apparatus extrinsic eye muscles
eyebrows function
filter sunlight and divert sweat
eyelids function
cover eye (protection) and lubricate eyes facilitate blinking
eyelashes function
filter for dust particles
base has root hair plexus around it
blinking
an involuntary thing
when something touches the eye we blink
blinking moves around fluid in eye
conjunctiva
transparent mucus membrane on inside of eyes
lacrimal apparatus
liquid producing gland in the eye
made of the lacrimal gland and lacrimal duct
lacrimal gland
located on anterior lateral portion of eyeball (like below eyebrow arch)
secretes liquid, which exits onto eye; then blinking moves liquid around
lacrimal duct
“tear duct”
on medial side of eye
drains liquid from eyeball into nose
why does our nose get runny when we cry or when our eye is irritated?
the lacrimal duct, which drains liquid from the eye, drains this liquid through the nose
extrinsic eye muscles
there are 3 on each side (6 total)
moves eye within the socket
nystagmus
eyes jittering back and forth
high/drunk driving test
3 meta structures of the eyes
tunics
humors
lens
tunics
wall of eyeball, provide the ball shape fibrous tunic (outermost) vascular tunic (uvea; middle) sensory tunic (retina; innermost)
fibrous tunic
outermost tunic, functions in protection
contains sclera and cornea
sclera
white part of eye that extends all the way around back
part of fibrous tunic
cornea
transparent part of eye right over the front of the eye
part of fibrous tunic
vascular tunic
aka uvea
middle tunic layer (immediately deep to fibrous)
contains choroid, ciliary body, and iris
choroid
layer of eye full of blood vessels to nourish eye and allow exchange
part of vascular tunic
ciliary body
intrinsic eye muscles that attach to lens by the suspensory ligaments for focusing
modification of choroid that goes completely around lens
suspensory ligaments function
connect ciliary body to lens
iris
modification of choroid that is only in front of the lens
highly pigmented (genetically determined)
contains pupil (hole in iris)
part of vascular tunic
sensory tunic
aka retina
innermost tunic
highly neural sensory portion of eye
contains pigmented layer and neural layer
humors of the eye
fluids within the eye that help it to maintain shape
vitreous humor and aqueous humor