psychobio exam 4

transduction

stimuli becomes electrochemical signals

sensation

nerves picking up a stimulus

perception

brains interpretation of a stimulus

sensitivity threshold

minimum stimuli present to be detected

shift left = more sensitive

shift right = less sensitive

amplitude

volume/loudness of sound

frequency

pitch of sound

speed of a sound wave

faster in liquid and hot air

liquid = cells are close together so sound moves through them faster

hot air = molecules already more excited so they transfer the energy faster

decibels (dB)

measures the volume/amplitude of sound

pinna

outer fleshy part of ear

helps with localization by focusing sound

ear cannal

part of the outer ear that collects sound in a cave like chamber

tympani membrane

separates outer and middle ear

makes sounds into vibrations to be carried out into the middle and inner ear

ossicles

3 small bone structures that send vibrations from tympanic membrane to inner ear

3 parts of the ossicles

maaleus (hammer)

incus (anvil)

stapes (stirrup)

cochlea

swirled up inner ear canal structure with hairs to detect sound vibrations and convert them into AP

basilar membrane

surface where hair cells of cochlea pertrude

creates tonotopic organization and helps distinguish frequency for the cochlea

inner hair cells (IHC)

hair cells near the base of the cochlea (outer pair where it starts to curl) and detects high frequencies

damaged first because theyre the the most outside/encountered first

outer hair cells (OHC)

hair cells near the apex (curled part of cochlea) that detects low frequencies

how auditory stimuli is transduced

the hair cells in the cochlea feels the vibrations made and their movement causes AP

tonotopic organization in the cochlea

organization of receptors based on frequencies and present in all auditory processing

tonotopic organization in the auditory cortex

anterior (front) = lower frequencies

posterior (back) = higher frequencies

cranial nerve VIII

sensory

gives hearing and balance

functions of auditory cortex

detects more complex sounds like voices, speech, music, and not just hearing in general

sound localization and what helps in the process

determine where sound comes from

pinna, interaural intensity, interaural latency

interaural intensity

sound localization based on comparing sounds between the two ears to see which is louder/higher pitched

interaural latency

sound localization based on comparing time it takes for sound to reach one ear or the other

echolocation

using sound to navigate surroundings by sensing the vibrations sound waves make when they bounce off an object and back towards you

conduction deafness

hearing loss before cochlea

usually because something is blocking

sensorineural deafness

vibrations in cochlea can’t become AP

damage to hair cells or cranial nerve VIII

central deafness

damages to auditory areas of the brain

cochlear implants

implant with an outside microphone that directly stimulates auditory nerve (CN VIII) by mimicking hair cells

balance is the function of which systems?

vestibular system, proprioception (somatosensory through muscles), visual system

3 semicircular canals

3 fluid filled tubes with hairs attached to cochlea that give info on head movement

vestibular sacs

fluid filled sacs to indicate head position

utricle

horizontal head positions

saccule

vertical head positions

where does transduction for vestibular system occur

mainly the semicurcular canals and their hair cells and CN VIII

motion sickness

caused by contradicting info of balance systems

sensory conflict theory

predicts motion sickness is caused by contradicting info from vestibular and visual system

flavor

perception of smell AND taste

olfaction

chemical sense of smell

odorants

ligands that bind to nose receptors

volatility

odorant molecules evaporate and flash of fast, allowing them to travel into the air and into our noses

orthonasal stimulation

odorants enter through the nose directly

retronasal stimulation

odorants enter through the mouth and then the nose

primary stimulation for taste

odor receptor genes

~390 in humans

odor receptors coding of odorants

odorants activate specific like letters making a word through the receptors for your brain to perceive a smell

olfactory epithelium

lining of nose with olfactory recepts

olfactory bulb

protruding mass from amygdala that then create branches of olfactory receptors

cribriform plate

small openings where olfactory nerves from the bulb can enter through to be in the nasal cavity

central projection pathway of olfactory sense/olfactory bulb

amygdala → thalamus → cortex

only sense to go to amygdala first rather than thalamus

limitations of human olfactory ability + compared to other animals

humans have very few receptors and have a smaller olfactory bulb, overall resulting in less sensitivity

we also smell things farther away rather than directly next to the item, making lower sensitivity

anosmia

cant smell

cranial nerve I

sensory

sense of smell

vomeronasal system

olfactory system for pheromones which is believed to affect behavior and physiology

pheromones

chemical of species that impact social and reproductive behavior and the physiology of members of the same species

humans and posession vomeronasal system

yes but inactive and nonfunctional

taste bud

clusters of taste receptors (about 50-150 per)

taste receptors

receptors that pick up one specific chemical and signify taste

taste pore

opening in a taste bud to let chemicals from food in for receptors to detect

lingual papillae

taste buds on the tongue

fungiform

anterior (front) 2/3 of tongue with buds distributed equally

foliate

poterior lateral parts of the tongue

taste buds in trenches

circumvallate

very back of the tongue

taste buds in little trench clusters that look like boats

extralingual papillae

taste buds off the tongue

soft palate (squishy part of the top back of your mouth), throat

adaptive roles of the basic tastes

• salty = triggered through thirst to show need of salt for homeostasis, AP, and body functions

• sour = something is poiled

• sweet = signals carbs and energy rich foods

• umami = signals presence of protein

• bitter = signals toxins

T1R family

T1R2 + T1R3 = sweet

T1R1 + T1R3 = umami

T2R family

bitter tastes

40 taste receptors for wide toxic detection

transduction of basic tastes

ionotropic = salty and sour

metabotropic = sweet, bitter, umami

how does miraculin work?

miraculin activates sweet receptors in high acidic environments

ex: lemon is very acidic, so it allows miraculin to activate sweet receptors to perceive the lemon as both sour and sweet

pseduogenes in certain species

some animals lack specific genes and cant pick up specific tastes

ex: pandas lack T1R1= cant taste umami

presence of other basic tastes

plausible yes and currently being researched

includes some like fatty, starch, and calcium

super tasters vs nontasters

both caused by differences in the density of papillae (taste bud bumps)

super tasters = high density

nontasters = low densisty

cranial nerve VII

sensory + motor

overall taste and facial expression

cranial nerve IX

sensory + motor

taste from back of tongue

swallowing + speech

cranial nerve X

sensory + motor

taste from throat

swallowing + speech

thalamacortical pathway vs. olfactory central projection pathway

thalamacortical: goes to thalamus first to be sent to cortex

olfactory path: goes to amygdala first then thalamus then cortex

causes of taste disorders

upper respitory/middle ear infections

surgery/treatments to head/neck area

head injury