Sensory Systems

lens

what structure helps light focus on fovea?

long distance

lens is less curved

short distance

lens is more curved

proteins inside the lens become rigid over time

why does the lens’ ability to curve deteriorate?

ganglion to bipolar neuron to photoreceptors

order of light hitting

photopigments (rhodopsin) inside photoreceptors have conformational change

how does light activate the second messenger system and eventually trigger cell depolarization/neurotransmitter release?

rods

located in peripheral

high light sensitivity

big receptive field

one type

high convergence, low acuity

cones

located in fovea

low light sensitivity

three types

high acuity, low convergence

dark

in what conditions is cyclic GMP present?

dark conditions means cyclic GMP is present, it opens the cyclic GMP gated ion channels, Ca2+ and Na+ flow in (depolarizing the cell), neurotransmitters are released from the bipolar neurons

explain dark current conditions/process

frequency (pitch) and amplitude (loudness)

sound is measured by

pinna and acoustic meatus

outer ear components

tympanic membrane (eardrum) ossicles, eustachian tube, tensor tympani

middle ear components

eustachian tube

goes to the throat

function: balancing the pressure between middle and outer ear

tensor tympani

muscle that tightens the ossicles and makes them less sensitive to sound changes

cochlea and vestibular branch

inner ear components

endolymph

makes sure the spiral organ can vibrate and transfer sounds into neuronal signals

sound pushes liquid in upper tube and liquid in bottom tube flows out

what occurs in cochlea?

basilar membrane

bottom membrane

hair cells are attached there

tectorial membrane

top membrane

has a lot of K+ meaning when K+ channels open, K+ will flow into the cell

what is different about endolymph?

mechanically gated K+ ion channels

what type of channels do hair cells have?

hair cell and ganglia cell that picks up neurotransmitters, generates action potential, and sends it to the brain

what two cells are involved in passing on auditory signals?

high frequency

the thicker/narrower part of the basilar membrane detects

low frequency

the thinner/wider part of the basilar membrane detects

otoliths

what liquid is present for the vestibular branch?

time difference is calculated (right cochlea activated, action potential compares time diff with sound detected from left cochlea)

how does our auditory system locate sound?

medulla oblongata

where does the time difference calculation occur?

hair cells

vestibular branch

medulla oblongata

thalamus

cerebral cortex

auditory signal pathway

upper nasal cavity

olfactory bulb

olfactory tract

olfactory cortex

limbic system and cerebral cortex

olfactory system pathway