201 Ch18- special senses

receptor

protein that responds to signal molecules

receptors located

extracellularly & intracellularly

receptors by sensory location

exteroceptors (outside body)

proprioceptors (body position)

interoceptors (inside body)

receptors by nature of the stimulus

nociceptors(pain),

thermoreceptors (temperature),

photoreceptors (light),

mechanoreceptors (pressure),

and chemoreceptors (chemicals).

electromagnetic

receptor involved in vision/ hearing

mechanoreceptors

receptors that respond to stretch, compression, or distortion

3 mechanoreceptors

tactile receptors

baroreceptors

proprioceptors

Baroreceptors

stretch of organs due to pressure

smell

chemoreceptors & CN 1

Ear divisions

external

middle

and internal ear

ossicles found in

middle ear

malleus attached to

tympanic membrane & incus

stapes covers

oval window

muscles- middle ear

protect eardrum and ossicles from loud sounds

auditory tube

equalize air pressure

internal ear consists of

bony / membranous labyrinth

perilymph

fluid separates bony and membranous labyrinth

endolymph

fluid found in membranous labyrinth

Hair cells

are receptors found in ampulla

bony labyrinth subdivisions

vestibular complex & cochlea

semicircular canals -3 tubes

help maintain balance and equilibrium

equilibrium

= semicircular canals (vestibule/utricle/ saccule)

endolymph -dizziness

moving fluid within ear that causes bending of hair cells

-multiple directions symptom

otoliths - crystals

distort hair cells and trigger electrical impulse in the hair cells

bipolar neuron

transmit info about balance and spatial orientation to the brain(vestibular ganglia)

vestibular nerve

extends out of vestibular ganglion

cochlea- 3 fluid-filled canals

scala vestibuli- perilymph

scala tympani- perilymph

scala media- endolymph

cochlea has

organ of Corti

organ of Corti

basilar membrane

tectorial membrane

hair cells

nerve fibers

tectorial membrane

comes into contact with hair cells in OoC

-distorted by sound waves

pressure waves

created by vibrations at the oval window

travel thru perilymph

sensory neuron stimulation and nerve carrier

Pressure waves in perilymph distort the basilar membrane

This bends hair cells against the tectorial membrane

Hair cells release neurotransmitters

This stimulates sensory neurons

• cochlear nerve

CN 8

formed by vestibular/ cochlear nerve

eye - 3 layers

fibrous layer

vascular layer

inner layer (retina)

eye - 2 cavities (+ chamber/fluid)

Anterior Cavity- anterior/posterior chamber (aqueous humor)

Posterior Cavity- vitreous chamber (vitreous body)

aqueous humor

facilitates nutrient/ waste transport

vitreous body

supports shape of eye

photoreceptors + other cell types found in RETINA

photoreceptors: rods/cones

other: bipolar, horizontal, Amacrine, & ganglion cells

macula (photoreceptors)

cones

optic nerve (CN 2) exits

through optic disc

glaucoma

damage to the optic nerve

leading cause of blindness

Prevent glaucoma w

dilated eye exam/ image of back of the eye

NO CURE

detached retina

-fluid?

retina detaches from posterior wall

-vitreous fluid