NEU211 Chapter 8 EXAM 2 Part 2 (Smell)

smell helps us

find food, mates, avoid danger

olfaction =

sense of smell

example of olfaction in other animals

rats naturally avoid cet, fox, and predator smellls

smell communicates thru

pheromones

pheromones affect

reproductive behavior, territorial boundaries, identifying indiv, aggressio

smell affects social behavior study

men sweat collected when watching fear, disgust, or no emotion vid, women smelled samples

fear sweat samples caused mild

fear

disgust sweat samples caused

disgust

neutral sweat samples caused

no expression

ppl prefer smells of partners who are ___ from themselves/fam

diff

contraceptive pills ___ women’s preference for diff smelling partner

reduce

pregnant women are ___ sensitive to taste and smell

more

olfactory epithelium has 3 cell types

olfractory receptor cells, supporitng cells, basal cells

olfractory receptor cells

sense smell

supporting cells

keep tissue healthy

basal cells

stem cells replace old receptor cells

olfractory epithelium =

inside nose

the olfractory epitheliuj is covered by

thin layer of mucus

mucus is replaced every ___ min

10

mucus layer function

dissolve odorants

odorants

smell chem stimuli

mucus is made of

water w mucopolysaccharides, proteins, salt

bigger olfractory epitheliujm surface area causes __ ability to smell

more

olfractory receptor neurons have

thin dendrite w small end knob at epithelium surface, unmyelinated

there are long ___ in mucus at the knob

cilia

odor molecules dissolved in mucus bind to cilia and activate

smelling process

smelling process =

olfractory nerve/cn 1, cribriform plate, olfractory bulb

cribriform plate =

bony structure in skull

anosmia

cant smell

olfractory transduction sequence

odorant binds to receptor, g protein golf, adenylyl cyclase on, camp, camp binds to channels, channels open, na ca influx, cl channels open, depolarization, signal to brain

metabotrophic receptor

gpcr

isotrophic receptor

bind to channel

g protein olfractory receptors use

gold

3 ways how odorants disappear

diffuse away, mucus enzymes break them down, camp activates other signals to stop smell

adaptation

if oder stays, receptor cell response fades in 1 min

adaption is why smells seem ___ over time

weaker

olfaction uses

pop coding

diff patters =

diff smells

diff olfractory receptor cells have ___ concentration thresholds

diff

central okfactory pathway

olfactory receptor neurons, glomeruli in olfactory bulb, 2nd order neurons, olfactory tract, brain

olfactory receptor neurons send ___ to olfactory bulbs

axons

glomeruli

spheres in olfactory bulb, recognizes signals

sensory map

neurons in specific place in bulb respond to diff oders

2nd order olfactory nbeurons

recive signals from glomeruli

olfactory tract

send signals deeper into brain

__ brain structures get signals from olfactory connections

many

bc olfactory bulbs can send output axons to diff parts of brain, smell can affect

emotions, memory, behavior

olfactory cortex

where smells are processed in brain

conscious perception of smell

olfactory tubercle, medial dorsal nucleus of thalamus, orbital frontal cortex

we can tell diff between diff smells bc of

pop coding, spatial maps, temporal soding

temporal coding

timing of ap in neurons

diff odors hase ___ temporal coding patterns

diff

who are better at detecting odors

women

repeated attention to faint smell make women ___ sensitive to it

more

___% of olfactory receptor genes are diff for everyone

30