SENSES Flashcards
means by which the brain receives information about the environment and body
senses
process initiated by stimulating sensory receptors
sensation
conscious awareness of those stimuli
perception
what are the five senses
smell, touch, taste, vision, and hearing
two basic groups of senses
general senses and special senses
have receptors distributed over a large part of the body
general senses
divisions of general senses
somatic and visceral senses
provide sensory information about the body and environment
somatic senses
provide information about various internal organs primarily involving pain and pressure
visceral senses
the receptors of these senses are more specialized in structure and are localized to specific parts of the body
special senses
what are the special senses
touch, taste, smell, vision, and balance
are sensory nerve endings or specialized cells capable of responding to stimuli by developing action potentials
sensory receptors
respond to mechanical stimuli such as bending or stretching
mechanoreceptors
respond to chemicals such as odor molecules that allow us to perceive smell
chemoreceptors
respond to light
photoreceptors
respond to temperature changes
thermoreceptors
respond to stimuli that result in the sensation of pain
nociceptors
what are the general senses
touch, pressure, pain, temperature, vibration, itch, and proprioception
sense of movement and position of the body and limbs
proprioception
the simplest and most common types of sensory receptors are
free nerve endings
what are the receptors for temperature
cold or warm receptors
respond to decreasing temperatures but stop responding at temperatures below 12C or 54F
cold receptors
respond to increasing temperatures but stop responding at temperatures above 47C or 117F
warm receptors
structurally more complex than free nerve endings
touch receptors
are small superficial nerve endings involved in detecting light touch and superficial pressure
merkel disks
associated with hairs ; also involved in detecting light touch
hair follicle receptors
receptors for fine, discriminative touch and are located just deep to the epidermis
meissner corpuscles
deeper tactile receptors and play an important role in detecting continuous pressure in the skin
ruffini corpuscles
deepest receptors and are associated with tendons and joints (proprioception)
pacinian corpuscles
enables us to maintain an upright position even if our body is on uneven ground
righting reflex
is characterized by a group of unpleasant perceptual and emotional experiences
pain
two types of pain sensation
- localized, sharp, pricking, or cutting pain resulting from rapidly conducted action potentials
- diffuse, burning, or aching pain resulting from action potentials propagated slowly
it suppresses action potentials from pain receptors in local areas of the body through the injection of chemical anesthetics near a sensory receptor or nerve
local anesthesia
pain sensation suppressed by loss of consciousness ; treatment where chemical anesthetics that affect the reticular activating system are administered
general anesthesia
perceived to originate in a region of body that is not the source of the pain stimulus
referred pain
sense of smell is also called
olfaction
olfaction occurs in response to airborne molecules called
odorants
these are bipolar neurons within the olfactory epithelium
olfactory neurons
it lines the superior part of the nasal cavity
olfactory epithelium
axons from olfactory neurons form olfactory nerves which pass through foramina of the cribriform plate and enter the _
olfactory bulb
there the olfactory neurons synapse with interneurons that relay action potentials to the brain through the _
olfactory tracts
each olfactory tracts terminate an area of the brain called the _ ; located within the temporal and frontal lobes
olfactory cortex
feedback loop plus temporary decreased sensitivity at the level of the receptors results in an
adaptation
the sensory structures that detect stimuli are called
taste buds
taste buds are oval structures located on the surface of certain _ which are enlargements on the surface of the tongue
papillae
how many taste cells
40
each taste cell contains hairlike processes called _ that extend through a tiny opening in the surrounding stratified epithelium
taste hairs
the surrounding stratified epithelium is called
taste pore
what are the five taste sensations
sour
salty
bitter
sweet
umami
taste sensations are carried to the brain by three cranial nerves which are
the facial nerve
the glossopharyngeal nerve
the vagus nerve
transmits taste sensations from the anterior two-thirds of the tongue
facial nerves
carries taste sensations from the posterior one-third
glossopharyngeal nerve
carries some taste sensations from the root of the tongue
vagus nerve
the visual system includes the _
eyes, accessory neurons and sensory neurons
housed within bony cavities called orbits
eyes
what are the accessory structures of the eye
eyebrows, eyelids, conjunctiva, lacrimal apparatus, and extrinsic eye muscles
protect the eyes by preventing perspiration from running down the forehead and into the eyes causing irritation
eyebrows
protect the eyes from foreign objects
eyelids
is a thin, transparent mucous membrane covering the inner surface of the eyelids and the anterior surface of the eye
conjunctiva
consists of lacrimal gland situated in the superior lateral corner of the orbit and a nasolacrimal duct and associated structure in the inferior medial corner
lacrimal apparatus
produces a fluid we call tears which pass over the anterior surface of the eye
lacrimal gland
excess tears are collected in the medial angle of the eyes by small ducts called
lacrimal canaliculi
canaliculi open into a _
lacrimal sac
lacrimal sac is an enlargement of the
nasolacrimal duct
how many extrinsic eye muscles are attached
6
two muscles located at an angle to the long axis of the eyeball
superior and inferior oblique muscles
the wall of the eyeball is composed of three tissue layers or
tunics
consists of the sclera and cornea
fibrous tunic
consists of the choroid, ciliary body, and iris
vascular tunic
consists of the retina
nervous tunic
it is the firm, white, outer connective tissue layer of the posterior five-sixths of the fibrous tunic which helps maintain the shape of the eye, protects the internal structures and provide attachment sites for the extrinsic eye muscles
sclera
the transparent anterior sixth of the eye which permits light to enter
cornea
the middle tunic of the eye is called the _ because it contains most of the blood vessels of the eye
vascular tunic
the posteriori portion of the vascular tunic is called the _ which consists of a vascular network and many melanin-containing pigments causing it to appear black
choroid
vascular tunic consists of the
ciliary body, choroid and iris
continuous with the anterior margin of the choroid ; it contains smooth muscles
ciliary body
the smooth muscles in the ciliary body are called
ciliary muscles
ciliary muscles attach to the perimeter of the lens by
suspensory ligaments
it is a flexible biconvex, transparent disc
lens
the colored part of the eye which is attached to the anterior margin of the ciliary body, anterior to the lends
iris
the iris is a contractile structure consisting mainly of smooth muscle surrounding an opening called the
pupil
it covers the posterior five-sixths of the eye and is composed of two layers
retina
two layers of retina include
pigmented retina and sensory retina
keeps light from reflecting back to the eyes
pigmented retina
contains photoreceptor cells as well as numerous interneurons
sensory retina
what are the photoreceptor cells
rods and cone
20 times more common than cones ; can function in dim light because they are very sensitive, they require low levels of light to be stimulated ; dont provide color vision
rods
require much more light and they do provide color vision
cones
three types of cones sensitive to different colors such as
blue
green
red
is a small spot near the center of the posterior retina
maculae
the center of the macula is a small pit called _ ; it is the part of the retina where light is most focused when the eye is looking directly at an object ; it contains only cone cells ; discriminate fine images
fovea centralis
white spot just medial to the macula through which a number of blood vessels enter the eye and spread over the surface of the retina ; also the spot at which axons from the retina meet ; no photoreceptor cells and does not respond to light
optic disc
the optic disc contains no photoreceptor cells and does not respond to light, it is therefore called
blind spot of the eye
interior of eyeball is divided into three areas called
anterior chamber
posterior chamber
vitreous chamber
the anterior and posterior chambers are filled with _ which help maintain pressure within the eye, refracts light, and provides nutrients to the inner surface of the eye ; produced by ciliary body as a blood filtrate ; keeps the eye inflated
aqueous humor
if the pressure of the eye increases it results to a condition called
glaucoma
the vitreous chamber of the eye is filled with a transparent jellylike substance called _ which help maintain pressure within the eye and holds the lens and the retina in place ; it also refracts light
vitreous humor
as light passes from air to some other denser transparent substance, the light rays are
refracted
if the surface of the lens are concave the light rays are _
bent
if the surface is convex, the light rays _
converge
the crossing point is called the _ ; it occurs anterior to the retina
focal point
causing light to converge is called
focusing
process of changing the shape of the lens is called
accommodation
rod photoreceptors contain a photosensitive pigment called
rhodopsin
rhodopsin consists of a protein called
opsin
opsin is loosely bound to a yellow pigment called
retinal
the manufacture in rods requires what vitamin
vitamin A
what forms rhodopsin?
retinal and opsin
a person with vit A deficiency may have a condition called
night blindness
night blindness can result from _ which is the separation of the sensory retina from the pigmented retina ; affects periphery of retina where rods are located
retinal detachment
the image seen by the eye is the visual _ of that eye
field
bipolar and horizontal cels synapse with ganglion cells to form the
optic nerve
misalignment of two eyes is the most common cause of what condition
diplopia or double vision
three areas of each ear
external ear
middle ear
inner ear
part extending from the outside of the head to the tympanic membrane commonly called the eardrum
external ear
air-filled chamber medial to the tympanic membrane
middle ear
set of fluid-filled chambers medial to the middle ear
inner ear
the fleshy part of the external ear on the outside of the head ; collects sound waves and directs them toward the external auditory canal which transmits them to he tympanic membrane
auricle
auricle opens into the _ a passageway that leads to the eardrum
external auditory canal
skin that lines the auditory canal has both hair and
ceruminous glands
the ceruminous glands produce _ a modified sebum commonly called earwax
cerumen
a thin membrane that separated the external ear from the middle ear ; consists of a thin layer of connective tissue sanwiched between two epithelial layers
tympanic membrane or eardrum
two covered openings on the medial side of the middle ear which connect the middle ear with the inner ear
oval window
round window
the middle ear contains three auditory ossicles which are
malleus
incus
stapes
it is attached to the medial surface of the tympanic membrane
malleus
it connects the malleus to the stapes
stapes
opens into the pharynx and enables air pressure to be equalized between the outside air and the middle ear cavity
auditory tube or eustachian tube
the inner ear consists of interconnecting tunnels and chambers within the temporal bone called the
bony labyrinth
inside the bony labyrinth is smaller set of membranous tunnels and chambers called the
membranous labyrinth
the membranous labyrinth is filled with a clear fluid called
endolymph
the space between the membranous and bony labyrinths is filled with a fluid called
perilymph
3 regions of the bony labyrinth
cochlea (hearing)
vestibule (balance)
semicircular canals (balance)
shaped like a snail shell and contains a bony core shaped like a screw
cochlea
the threads of the screw of cochlea are called
spiral lamina
three channels of cochlea include:
scala vestibuli
scala tympani
cochlear duct
extends fro the oval window to the apex of the cochlea
scala vestibuli
extends in parallel with the scala vestibuli from the apex back to the round window
scala tympani
wall of the membranous labyrinth that lines the scala vestibuli is called the
vestibular membrane
wall of labyrinth that lines the scala tympani is the
basilar membrane
formed by space between the vestibular membrane and the basilar membrane and is filled with endolymph
cochlear duct
inside the cochlear duct ; specialized structure ; contains specialized sensory cells
spiral organ
specialized sensory cells are called which have hairlike microvilli, often referred to as stereocilia
hair cells
hair tips are embedded within an acellular gelatinous shelf called the
tectorial membrane
cell bodies are located within the
cochlear ganglion
2 major steps of the process of hearing
conduction of sound waves (outer, middle, inner)
stimulation of hearing receptors (inner)
is the frequency or wavelength of sound
pitch
related to the amplitude of the sound wave
volume
categories of hearing impairment
conduction deafness
sensorineural hearing loss
results from mechanical deficiencies
conduction deafness
caused by deficiencies in the spiral organ or nerves
sensorineural hearing loss
2 components of balance or equilibrium
static
dynamic
associated with the vestibule and is involved in evaluating the position of the head relative to gravity
static
associated with the semicircular canals and is involved in evaluating changes in the direction and rate of head movements
dynamic
this is found in the inner ear
vestibule
two chambers of vestibule
utricle
saccule
specialized patches of epithelium found in each chamber of vestibule ; it contains hair cells
maculae
tip of microvilli are embedded in a gelatinous mass called the
otolithic membrane
membrane is weighted by this ; particles composed of protein and calcium carbonate
otoliths
base of each semicircular canal is expanded into an
ampulla
within ampulla, epithelium is specialized to form a
crista ampullaris
each crista consists of a ridge of epithelium with a curved gelatinous mass
cupula
continuous stimulation of the semicircular canals can cause
motion sickness
complex sensation involving sensory input to the vestibular nucleus
balance
