ch. 15 17 Flashcards
2 major types of receptors
general senses
special senses
temp, pain, touch, pressure, vibration,and proprioception (body position)
general senses
where is info from the general senses sent to
primary sensory cortex
where is info from the special senses sent to
specific areas of cortex
reduction in sensitivity in the presence of a constant (and painless) stimulus
sensory adaptation
ex of sensory adaptation
hot bath water
room with strong odor
2 processes of adaptation
peripheral adaptation
central adaptation
level of receptor activity changes- strong responses at first and it gradually declines;
reduced the amount of info that reaches CNS
peripheral adaptation
involves inhabitation of responses within CNS
central adaptation
how can the higher centers alter receptor sensitivity
ex you focus on the sense- heightens awareness “listen carefully”
why is the difference between somatic and visceral receptor
location
4 types of general sense receptors
thermoreceptors
nociceptors
mechanoreceptors
chemoreceptors
receptor for temp
thermoreceptors
receptor for pain
nociceptors
receptor for physical distortion
mechanoreceptors
receptor for chemical concentration
chemoreceptor
located in dermis, skeletal muscles, liver and hypothalamus
thermoreceptors
where are temp sensations sent to in the brain
reticular formation and thalamus
function of nociceptors
protective function
nociceptors are sensitive to what 3 items
temp extremes
mechanical damage
dissolved chemicals
2 types of axons that carry painful sensations
fase pain (quickly reach primary sensory cortex- quick conscious attention) slow pain (burning and aching pain- cause generalized activation of reticular formation and thalamus)
nociceptor adaptation
little/no peripheral adaptation
central adaptation may decrease perception of pain
2 chemicals released by the cns in response to excessive pain
enkephalins and endorphins
3 type of machanoreceptors
tactile receptors
baroreceptors
proprioceptors
detect touch, pressure, and vibration
tactile receptors
detect pressure changes in b.v. and in portions of digestive, respiratory and urinary tracts
baroreceptors
monitor position of joints, tension in tendons and ligaments and the state of muscular contraction
proprioceptors
ex of chemoreceptors in the body
pH and CO2 monitored in CSF
what type of tract carries sensory info to the brain
sensory/afferent pathways
what type of tract carries motor info to the brain
motor/efferent pathways
sense of smell; in nasal cavity
olfaction
2 types of cells found in the olfactory epithelium
basal cells
olfactory receptor cells
type of stem cells- divide and turn into new receptor cells
basal cells
highly modified bipolar neurons with cilia shaped dendrites w receptors on exposed surface
olfactory cells
what type of neurons are olfactory receptor cells?
bipolar
explain why olfaction is connected to emotion and memories
info to the hypothalamus and limbic system explains emotional and behavioral responses and memories triggered by certain smells
what is the effect of aging on olfaction
receptor number decreases and remaining receptors become less sensitive with age
sense of taste; taste receptors on surface of tongue and parts of pharynx and larynx
gustation
two cells found is taste buds
basal cells
gustatory receptor cells
type of stem cells that divide and turn into new receptor cells
basal cells
have extensions of microvilli= taste hairs
gustatory receptor cells
what only lives about 10 days until they are replaced
gus. receptor cells
what is the connection of smell and taste
level of stimulus of olfactory receptors play large role in taste perception (things taste better when you can smell them)
6 taste sensations
sweet salty sour bitter water umami
why do certain taste sensations are triggered more than others
threshold for receptor stimulus varies with each primary taste; respond more readily to unpleasant than to pleasant stimuli
which taste sensations are triggered more than others
bitter (toxins) and sour (acids) are triggered first- cause harm
it is for protection/survival
what is the effect of aging on taste buds
decrease taste buds ; elderly may find food bland and unappetizing
eye accessory structures
eyelids
lacrimal caruncle
conjunctiva
lacrimal apparatus
fx. blinking- keeps eye surface lubricated and remove dust and debris
eyelids
another name for eyelid
palpebrae
soft tissue in corner of eye
fx. makes eye boogers -thick secretions
lacrimal caruncle
epith covering of inner surfaces of eyelids and outer surface of eye
conjunctiva
fx. secretes tears
lacrimal apparatus
decrease friction; remove debris; prevent bacterial infection via antibacterial enzyme-lysozyme; provides nutrients and O2 to portions of cornea
tears secreted in the lacrimal apparatus
prevent bacterial infection via antibacterial enzyme
lysozyme
3 layers/tunics of the eye
outer fibrous layer
intermediate vascular layer
inner neural layer
mechanical support and some protection
attachment site for extrinsic eye muscles
contains structures that assist in focusing
fx of fibrous layer
white of the eye
sclera
tough, outermost covering
sclera
transparent anterior portion of sclera
cornea
has no blood vessels and is quite sensitive (many free nerve endings)
cornea
fx. is window of eye and helps focus entering light rays
cornea
choroid colliery body suspensory ligaments iris pupil
vascular layer
vascular layer between sclera and retina
choroid
many capillaries to deliver o2 and nutrients to retina
choroid
forms inner ring around front of eye
ciliary body
secretes aqueous humor
ciliary body
extend inward from cilia body
suspensory ligaments
fx. holds lens in place
suspensory ligaments
colored portion of eye that contains 2 layers of smooth muscle
iris
fx. control light intensity entering eye
iris
central opening of iris that changes sizes via iris muscle
pupil
fx. opening that light passes through as it enters eye
pupil
inner lining of eyeball and has two layers
retina
what are the two layers of the retina
outermost- pigmented (absorbs light)
inner- contains photoreceptors
why is the fovea the site of the sharpest vision
contains no rods and very increase of cones
where is the blind spot located
optic disk (optic nerve head)
why do we have a blind spot
no receptor cells
origin of optic nerve in back of eye
optic disc
2 cavities in the eye
anterior and posterior cavity
between cornea and lens and is filled with aqueous humor
anterior cavity
nourishes cornea and lens
forms fluid cushion
maintains shape of front of eye
fx of anterior cavity
interior or eyeball that is filled with vitreous humor
posterior cavity
fx. stabilizes shape of eye
posterior cavity
transparent and elastic
lens
fx. focus visual images on the photoreceptors via changing shape (accommodation)
lens
focus visual images on the photoreceptors via changing shape
accommodation
lens rounder
nearby objects
lens flattened
distant objects
lens loses transparency and becomes cloudy and opaque
cataract
2 photoreceptors found in the retina
rods and cones
very sensitive to light - night vision
rods
black and white vision
rods
see only general outlines
rods
conc is highest on periphery of retina
rods
why do rods only see general outlines
many rod nerve fibers converge and transmit impulses to brain on same nerve fiber
color vision
cones
sharp images and fine detail
cones
increase conc at fovea - detail vision
cones
decrease conc at periphery of retina
cones
why do cones have sharp images and fine details
nerves don’t coverge like rods- can pinpoint stimulation accurately
a visual pigment
rhodopsin
where are rhodopsin located
in rods
what happens to rhodopsin in bright light
it breaks down; decomposes
what happens to rhodopsin in dim light
regenerated faster than its broken down; dark adapted
protein made of vitamin A
rhodopsin
where is color vision
in cones
what are the three types of cones
blue
green
red
occur through integration of info arriving from al 3 types of cones
color discrimination
one or more types of cones are nonfunctional
color blindness
what is the most common blindness
red green color blindness (red cones are missing)
3 regions of the ear
external ear
middle ear
internal ear
collects and directs sound waves
external ear
collect sound waves and transmit them to
middle ear
contains sensory organs for hearing and equilibrium
internal ear
pinna
auricle
fx. provides directional sensitivity
auricle
fleshly and cartilaginous outer ear
auricle
auditory canal
external acoustic meatus
channels sound toward
external acoustic meatus
eardrum
tympanic membrane
thin delicate sheet that separates external and middle ear
tympanic membrane
fx. vibrates with incoming sound waves
tympanic membrane
glands in skin of external acoustic meatus
ceruminous glands
fx. secrete ear wax
cerumen glands
tympanic cavity
middle ear
permits equalization of pressures on either side of tympanic membrane
auditory tube
what is the cause of otitis media
auditory tube allows microorganisms into middle ear
what are the auditory ossicles
malleus, incus, stapes
fx. carries vibrations of sound waves
auditory ossicles
where are the bony labyrinth and membranous labyrinth
internal ear
structures are surrounded by this bony structure (has receptors for hearing and equilibrium)
bony labyrinth
interconnected network of fluid filled tubes; inside of bony labyrinth and surrounded by fluid (perilymph)
membranous labyrinth
3 parts of the bony labyrinth
vestibule
3 semicircular canals
cochlea
fx. have receptors that provide sensations of gravity and linear acceleration
vestibule
fx. have receptors that are stimulated by rotation of the head
3 semicircular canals
fx. have receptors for hearing
cochlea
what is the significance of there being 3 semicircular ducts
each responding to one of the three rotational planes (anterior, posterior, and lateral)
where in the brain is equilibrium information is sent
on the vestibulocochlear nerve is sent to cerebellum and cerebral cortex
what is inside the cochlea
cochlear duct with spiral organ (organ of corti) which sits on basilar membrane
where are the hair cells
sit on basilar membrane and these hairs move against tectorial membrane and will cause sensory impulse
high frequency
short wavelength - vibrate nearer to oval window
low frequency
long wavelength- vibrate farther away from oval window
