BIO 168 Chapter 16

olfaction, gustation, vision, audition, equilibrium

5 special senses

sensation

a stimulus we are consciously aware of

tactile receptors

abundant mechanoreceptors of skin and mucous membrane

phasic receptors

adapt rapidly; only respond to new stimuli

presbyopia

age-related change in vision

eyebrows

aid in nonverbal communication; prevent sweat from dripping into eyes

papillary reflex

alters pupil size in response to light

tonic receptor

an example of this receptor would be any pain receptors

phasic receptor

an example of this receptor would be pressure receptors

ora serratat

boundary between photosensitive and non photosensitive parts of retina

scala tympani

chamber of bony labyrinth adjacent to basilar membrane

scala vestibuli

chamber of bony labyrinth adjacent to vestibular membrane

lens

changes shape to focus light on retina

sprinter papillae muscle

circular fibers that constrict pupil with parasympathetic nervous system activity

vestibule

contains utricle and saccule

transducers

convert stimulus energy into electrical energy

phototransduction

converting light to electrical signal

cornea

convex transparent structure at front of the eye

receptors

convey signals to CNS by sensory neurons

limbus

corneal sclera junction

adaptation

decreased sensitivity to conscious stimulus

pitch

depends on frequency of the vibrating object

proprioceptors

detect body and limb movements

photoreceptors

detect changes in light intensity, color, and movement

thermoreceptors

detect changes in temperature

somatic nociceptors

detect chemical, heat, or mechanical damage to the body surface or skeletal muscles

chemoreceptors

detect chemicals dissolved in fluid

mechanoreceptors

detect distortion of cell membrane

visceral nociceptors

detect internal organ damage

nociceptors

detect painful stimuli

exteroceptors

detect stimuli from external environment

interoceptors

detect stimuli from internal organs

olfaction

detection of odorants dissolved in the air

intensity of a stimulus

determined by how many nerve signals reach CNS

location of a stimulus

determined by which receptive field is active

cataracts

difficulty focusing on close objects; usually a result of aging; reduced visual clarity and color intensity

dilator papillae muscles

dilates pupil with sympathetic nervous system activity

glaucoma

disorder that is characterized as an increase of intraocular pressure

tympanic membrane

eardrum

chemoreceptors

example would be smell of food and oxygen levels in blood

thermoreceptors

example would be the receptors in skin and hypothalamus

mechanorecpetor

example would be the receptors in the stomach respond to stretch when the stomach fills up, stimulated the stomach to release contents into the small intestines

photoreceptor

example would be the retina in the eye

3 steps focusing of light

eyes converge, lens accommodates, and pupil constricts

hyperopia

far-sighted

aqueous humor

fluid that circuits through pupil in anterior chamber; production, circulation and drainage

visceral sensory receptors

found in walls of internal organs, monitor stretch, chemical environment, temperature, and pain

auricle

funnel-shaped visible part of the ear

iris

gives eye color

cochlea

houses membranous cochlear duct

otitis media

infection of the middle ear

retina

internal tunic

retinal neural layer

layer of retina that houses photoreceptors and associated neurons; receives light and converts it to nerve signals

retinal pigmented layer

layer of retina that is attached to choroid; provides vitamin A for photoreceptors; absorb stray light to prevent light scatter

bony labyrinth

maze-like spaces in temporal lobe; contains perilymph

membranous labyrinth

membrane-lined, fluid-filled tubes within bony labyrinth; contains endolymph

volatile molecules

molecules that are airborne/evaporative

myopia

near-sighted

emmetropia

normal vison (20/20)

choroid

nourish retina, make melanin to absorb extraneous light

taste buds

onion shaped organs housing taste receptors

pupil

opening in the center of the iris connecting the anterior and posterior chambers of the eye

referred pain

pain signal that has inaccurate localization;can not give an exact location of the pain example: appendicites, heart pain

folliate papillae

papillae that are leaflike ridges; not well developed; house a few taste buds in early childhood; located on posterior lateral tongue

fungiform papillae

papillae that are mushroom-shaped; each contain few taste buds; located on tip and sides of tongue

vallate papillae

papillae that are the largest and least numerous; contain most of the taste buds; located in a row of 10-12 along posterior tongue surface

cones

photoreceptor that are concentrated on fovea centralis; activated by high intensity light; allow color vision

rods

photoreceptor that is highly sensitive; activated by dim light;

eyelashes

prevent objects from coming into contact with the eye

gustatory pathway

primary neuron in cranial nerve brings signal to solitaries within medulla; signal is relayed to thalamus; signal is then relayed o primary gustatory cortex for conscious taste

sensory receptors

provide information about external and internal environment

phantom pain

sensation/pain associated with a removed body part

olfactory epithelium

sense of smell sensory receptor organ

gustation

sense of taste

spiral organ

sensory structure for hearing within the cochlear duct

filiform papillae

short and spikes papillae that help manipulate food; contain no taste buds

tonic receptors

show limited adaptation; respond continuously

helicotrema

small channel connecting scala vestibule and scale tympani

special senses receptors

specialized receptors in complex sense organs of the head

constriction of pupil

sphincter papillae contraction shrinks hole

somatic sensory receptors

tactile receptors of skin and mucous membrane; proprioceptors of joints, muscles and tendons

malleus incus and stapes; auditory tube

takes up the middle ear

basal cells

taste bud cells that are neural stem cells and replace gustatory cells

gustatory cells

taste bud cells that detect tastants

supporting cells

taste bud cells that sustain gustatory cells

sour

taste sensation associated with acids

sweet

taste sensation produced by organic compounds

bitter

taste sensation that are produced by alkaloids (bases)

salt

taste sensation that are produces by metal ions

refraction of light

the "bending" of light that is required for sharp vision

receptive field

the distribution area of the endings of a sensory neuron

nitrous humor

transparent fluid in posterior chamber of the eye; supports retina; helps eye maintain shape

baroreceptors

type of mechanoreceptor that response to change in pressure

modality

type of stimulus based on "labeled line

unencapsulated tactile receptors

type of tactile receptor that are classified as dendritic ends of sensory neurons with no protective coat; examples: free nerve endings, root hair plexuses

encapsulated tactile receptors

type of tactile receptors that are wrapped by connective tissue or covered by glial cells; example: lamellate corpuscles, bulbous corpuscles, tactile corpuscles

astigmatism

unequal focusing; unequal curvatures in one or more refractive surfaces

accommodation of lens

when ciliary muscle contraction thickens lens

convergence of eyes

when extrinsic muscles pull eyes medially

sclera

white of the eye