Chapter 16 A&P II

General senses

skin, viscera

Special senses

eyes, ears, nose, tongue

Sensation

brain aware

Perception

brain interprets

Projection

sensation - from receptors

Adaptation

ignore stimuli

repeated, unimportant

Touch

skin 

Fine touch (epithelium)

tactile (meissner’s) corpuscles

tactile discs/merkel cells

root hair plexus 

Pressure, stretch (dermis)

lamellate (pacinian) corpuscles

ruffini corpuscles

Itch

free nerve endings

Warm receptors

25-45 degrees C (77-113F)

Cold receptors

10-20 degrees C (50-68F)

Pain - free nerve endings

mech damage, extreme temp, chemicals

not brain

do not adapt

type A vs type C fibers

Regulation

enkephalins, endorphins

Visceral pain

internal organs

referred pain

common pathway 

Proprioception body position

skeletal muscle tension

Proprioception muscle spindles

muscle/tendon junction

stretch - stimulation

stretch reflex

Proprioception golgi tendon organs

increased tension - stimulation

prevent excess contraction 

Smell

olfactory receptors

Chemoreceptors

upper nasal cavity

Olfactory epithelium

olfactory receptor cell

cilia

odorants

olfactory glands

mucus 

Basal cells

stem

Odorants

gas - dissolve in mucous

Impulse generation

odorant - CAMP

Na+ depol

Impulse path 

olfactory bulb

olfactory code

olfactory tract

limbic system

memory 

Pheromones

scent signals

attraction

mate selection

reproductive cycles

Taste

tongue

Lingual papillae circumvallate

100 taste buds

Lingual papillae fungiform

5 taste buds

Lingual papillae filliform

friction

Gustatory cell

modified epithelium

receptor

taste hairs

receptive

taste pore

basal cell

Chemical dissolve - saliva

bind to hairs

Primary tastes

sweet

sour

salty

bitter

umami 

water

calcium

Sweet, sour

chem gate channels

Salty, bitter, umami

2nd messenger

Water

pharynx

Taste

sensation tied with smell

Light refraction

bending

pass through

differing density

Convex lens 

converge light

cornea (75%)

lens 

Concave lens

diverge light

Image - retina

upside down

reversed

Accommodation

distance - affects light

More distance

20ft converge

Less distance

20ft difficult

change lens shape 

Ciliary body

contracts

ligaments relax

lens thickens 

Myopia

near

long eye

concave

Hyperopia

far

short eye

convex

Retina light path backward

ganglion cells

bipolar cells

horizontal/amacrine cells

» modify

photoreceptors

pigmented epithelium 

Rods

low light

BW

blurry 

Cones

high light

color

red, blue, green 

Retina photoreceptors distribution

not uniform 

Rods distribution

periphery

Cones distribution

fovea centralis

macula lutea

blind spot 

Retina photoreceptors structure

discs

» photopigment

rhodopsin 

opsin

retinal 

Visual pigments rods rhodopsin

opsin

retinal (A)

» dark = bent

Visual pigments rods light

retinal = straight

loses attachment

bleached

impulse is bipolar - ganglion 

Visual pigments cones photopsin

work as rods

higher threshold

Visual pigments cones colors

erythrolabe

chlorolabe

cyanolabe 

Visual pigments

color perception 

Visual pigments overlap

cones and rods

Light adaptation - darkness to light

rhodopsin bleached

glare

cones take over

60s

Dark adaptation - light to dark

cones stop

but, rods bleached

restore rhodopsin

slow 

Binocular vision

overlap fields

2 eyes

depth 

Hearing

sound path

Sound =

vibrations

Ear

air - bone - fluid

Sound path enters…

outer ear. auricle, external acoustic meatus, tympanic membrane

External acoustic meatus

ceruminous glands

Tympanic membrane

vibrates

Sound path transferred…

to middle ear

Ear ossicles (M, I, S)

vibrate

amplify 

Stapes

oval window

inner ear

fluid vibration 

Auditory tube

equalize

Inner ear labyrinth bony

perilymph

Inner ear labyrinth membranous

endolymph 

Semicircular canals

vestibule

Cochlea

bony, membrane

Scali vestibuli (P)

oval window

vestibular membrane

Cochlear duct (E)

organ of corti

Scali tympani (P)

basilar membrane

Organ of corti

hair cells - 4 rows. kinocilium, sterocilia

tectorial membrane 

Stapes - oval window

scali vestibuli (P)

vestibular membrane

Cochlear duct (E)

basilar membrane

bends hairs

impulse 

Scali tympani

round window

Sound path cochlea frequency

different area

basilar membrane 

Equilibrium vestibule

utricle, saccule

macula

hair cells 

Equilibrium body position

still

Hairs

otolithic membrane

statoconia (otoliths)

Gravity

sagging

hairs bend = impulse 

Dynamic

sudden movement

macula

falling 

Rotation

semicircular canals

Three planes

anterior

posterior

lateral 

Membranous canals

fluid

ampulla

crista ampullaris 

Crista ampullaris

hair cells

cupula 

What happens during rotation?

endolymph moves

cupula bends

hair cells

impulse