Ch. 15 Sensory Receptors

sensory receptors

specialized cells that respond to stimuli

free nerve endings

neurons with dendrites embedded in tissue that would recieve a sensation

encapsulated nerve endings

neurons with dendrites wrapped in CT that to make them more sensitive; helps with sense of touch

specialized receptor cells

neurons with fancy cells attached to them; found in taste buds, rods and cones

exteroceptor

senses external environment; touch receptors in skin

interceptor

senses internal organs and tissues; receptors that sense stretching of bladder when filled with urine

proprioceptors

found in muscles, tendons and joints, help sense movement and position

chemoreceptors

sense chemical stimuli and in blood where they detect O2 and Co2 presence

nociceptors

pain receptors found in most tissues

mechanoceptors

sense physical stimuli like pressure, vibration and pull of gravity

thermoreceptors

sense change in temperature

photoreceptors

used in vision

lacrimal apparatus

series of structures related to tears

canaliculi

tears leave the eye via this structure

extrinsic eye muscles

insert into surface of the eye'; can be consciously controlled

intrinsic eye muscles

ciliary body and iris

ciliary body

hidden inside and attaches to lens; allows you to switch your focus

iris

muscular sphincter that opens and closes pupil

sclera

white of the eye that is tough and protects and is a site for extrinsic muscles to attach

cornea

transparent cover that allows light in

choroid

layers of blood vessels that supply blood to the eye

retina

contains nervous tissue responsible for photoreception

photoreceptors

stimulated by photons of light

rods

respond to black and white wavelengths of light

cones

respond to colored wavelengths of light

optic disc

action potential travels here where all neural info is collected

aqueous humor

watery fluid that helps the eye keep its shape and nourishes it

vitreous humor

glassy fluid that helps some pressure on retina; contains immune cells

papillae

contain taste buds but also hold saliva to keep the tounge moist

taste buds

microvilli increase surface area and gather more tastes from food

gustatory receptors

gather info from microvilli; carry out and towards brain; allow us to recognize different tastes

olfactory epithelium

where molecules dissolve into mucus layer that helps transport them to smell receptors which signal to the olfactory bulb

auricle

flaps of skin and cartilage; the ear

ear canal

carries sound waves into skull through external auditory meatus of temporal bone

tympanic membrane

aka ear drum; vibrates with movement of air in soundwaves

ossicles

malleus, incus, stapes

malleus

attached to tympanic membrane and vibrates with it

incus

transmits vibration to stapes

stapes

attached to cochlea; as it vibrates it causes pressurized waves inside fluid-filled inner ear

auditory tube

helps equalize air pressure between middle ear and environment; normally closed but opens when swallowing or yawning

cochlea

for hearing

semicircular canals

for head rotation

vestibule

acceleration and special positioning

cochlear duct

middle passage containing organ of corti

organ of corti

where sensory receptors for hearing are found; contain hair cells

sterocilia

bends in response to movement; triggers nerve impulse

semicircular canals

3 ring like structures in the inner ear oriented at a right angle to each other; at the base are hair cells

capula

when you move your head, it bends the stereocilia, triggering an action potential that the brain interprets as head movements

otolithic organs

have a viscous gel called otolithic membrane on top of which sit heavy otoliths