Chapter 9 special senses Flashcards
What are general senses
receptors that are all of the body inside and outside.
Examples of general senses
Temperature
Pain (nociceptors)
touch (tactile)
Proprioception
What is proprioception
to know or sense where in space one’s body parts are,
Has its own organs in the inner ear, but is in other places of the body
What are special senses
Receptors are only found in specific structures in the head
Examples of special senses
Smell (olfaction) Taste (gustation) Vision Balance/equilibrium hearing
Define sensory receptors
are specialized cells or cell processes that monitor conditions inside or outside of the body. the “eyes and ears” of the nervous system
name 5 types of stimulus in receptors
Free nerve endings Mechanoreceptors Chemoreceptors photoreceptors Auditory receptors
free nerve endings
dendrites can see information directly and become the receptor
Free nerve ending examples
Pain (nociceptors):Most common in superficial skin, joint capsules, within periosteum, and around blood vessel walls. Most visceral organs and deep tissues have these.
Temperature (thermoreceptors): found in dermis, skeletal muscle, liver, and hypothalamus, 3/4 of them sense cold, 1/4 senses heat
Mechanoreceptors
respond to mechanical stimulus. Range from free nerve endings to specialized supporting structures (corpuscles). Sense something mechanical is changing (movement)
Examples of mechanoreceptors
Tactile: touch, pressure, and vibration, external
baroreceptors: pressure (in an organ)
proprioceptors: position
Chemoreceptors
Chemical hitting a receptor is the stimulus.
Ex: Taste and Smell, receptors for blood pH, CO2 and O2 levels
Photoreceptors
VISION!
Detection of light is the stimulus
senses photons
Auditory Receptors
HEARING!
detection of sound is the stimulus
sensation
all of the information arriving via afferent receptors
perception
conscious awareness of a sensation
adaptation
a reduction in sensitivity in the presence of a constant stimulus
toning out a certain stimulus because they are unimportant at the time
4 types of taste buds and where they are located
Sweet: tip of the tongue
Salty: front sides
sour: middle sides
bitter: back of the tongue
name the three major layers of the eye
Fibrous Layer
Vascular Layer
Retina
Name the two subtypes of the fibrous layer
Sclera: the white of the eye, made of dese fibrous connective tissue, continuous with the cornea, attached to 6 extrinsic eye muscles
Cornea: Transparent part of the fibrous layer, over the iris and pupil
Fibrous layer
most external layer of the eye
for mechanical support and some physical protection
Vascular layer
layer of the eye
where the blood and lymphatic vessels are. also regulates the amount of light going into the eye and secretes and absorbs aqueous humor
sublayers of the vascular layer
Iris
Ciliary body
Choriod
Iris
part of the vascular layer
Colored part: contains smooth muscle and pigment cells in addition to the blood vessels & loose connective tissue. Changes the diameter of the pupil, the opening in the middle. In the front
Cilliary body
Part of the Vasular later
Function: smooth muscle and suspensory ligament holding the lens in place posterior to the iris. Found deep to the junction between sclera and cornea. contains the muscles that adjust the shape of the lens to focus your sight
Choroid
Part of the vascular layer
Function: separates the sclera from the retina posterior to the ciliary body. hos all the blood vessels
retina
innermost layer of the eye, lining the posterior cavity; contains the photoreceptors
purpose of mucus
mucus makes it so that only chemicals that are able to dissolve into the air and through the mucous can get to the olfactory receptors
what percentage do we smell of the air we take in?
2%
you can stimulate more smell by either making the scent stronger or intentionally sniffing
which type of receptor is an olfactory receptor?
Chemo receptor
which nerves controls smell
CN 1 the olefactory nerve
name the two cavities in the eye
anterior cavity: between ciliary body, lens and cornea. Full of a clear, watery fluid called aqueous humor
Posterior cavity: between lens/ciliary body and retina. Full of a gelatinous substance called the VIREOUS body/gel (part of the vitreous humor)
Name the two parts of the eye’s anterior cavity
- Anterior chamber: between cornea and iris
- Posterior chamber between ciliary body
What helps to stabilize the shape of the eye
aqueous humor and the vitreous body
what part of the ciliary body holds up the lens
ciliary zonules
what part of the ciliary body connects the zonules to the rest of the ciliary body.
ciliary processes
process of the secretion and flow of aqueous humor
- Epithelial cells of the ciliary process secrete aqueous humor
aqueous humor then circulates around the posterior an anterior chambers of the anterior cavity. - in the anterior chamber near the lateral edges of the iris, the aqueous humor enters the scleral venous sinus which empties into veins in the sclera
what happens when the normal flow of the aqueous humor is blocked
causes over pressurizing the eye, and causes glaucoma that can rapidly cause blindness if not treated
which cranial nerve controls the superior oblique
CN 4 the trochlear nerve
which cranial nerve controls the inferior oblique
CN 6 the abducens
which cranial nerve controls the eye at rest
CN 3 oculomotor
What is Lacrimation
the making of tears
a constant flow of tears keeps the surface of the eyeball moist and clean.
Benefits of tears
reduce friction, remove debris, keep bacterial infections from happening, and provide nutrients and oxygen to the conjunctiva and cornea
What is the lacrimal apparatus
makes moves and removes tears
what is the lacrimal duct
tear gland
is superior and lateral to the eyeball
about the size of an almond
over 12 ducts empty tears into the space between the eyelid and eyeball.
what is the palpebrae
eyelids
blink tears medially toward the medial canthus (where you find sleepy seeds)
cornea
clear protective cover that refracts [bends] light toward the lens
aqueous humor
the space between the cornea and the lens
fluid similar to perilymph or CSF that fills the anterior chamber of the eye
Lens
the clear sphere that focuses light onto a specific area of your retina
Vitreous body
he clear colorless transparent jelly that fills the eyeball posterior to the lens
what parts of the eye does light have to pass through to get to the retina
cornea
aqueous humor
lens
vitreous body
what is the retina
innermost layer of the eye, lining the posterior cavity; contains photoreceptors; also called the inner layer
name two layers of the retina
Thick inner (internal) layer called the NEURAL PART
thin outer (external layer called the PIGMENTED PART
what does the retina’s neural part contain?
- The photoreceptors
- supporting cells and neurons that perform preliminary processing and integrating of visual information
- blood vessels supplying tissues that line the posterior cavity
function of the retina’s pigmented part
absorbs the light that passes through the neural part so you don’t get a visual echo of the image
name the two types of photoreceptors
rods and cones
rods
- function: do best in dim light
- very light sensitive
- have black and white vision
- on the sides of the retina, so can see things better from the sides of your eyes in the dark
- more rods than cones in the eye
Cones
- do best in bright light not dim
- receive red, green and blue
- how much you stimulate each cone color determines what color you see
- at the middle of the retina
macula
tan area that only contains cones
fovea
the center of the macula
- a shallow depression of the highest concentration of cones
- this is where light from where you are looking directly at strikes the retina
what are the 2 layer of smooth muscle in the iris that can change the diameter of the pupil
Sympathetic stimulation
and parasympathetic stimulation
sympathetic stimulation `
makes pupils dilate
parasympathetic stimulation
causes pupils to constrict
what muscles controls the thickness of the lens
Ciliary muscle
what is accommodation
the process of changing the thickness of the lines
how does the ciliary muscle control accommodation for close vision?
the ciliary muscles contracts causing a more rounded lens by pushing the side of the lens anterior and medially.
how does the ciliary muscle control accommodation for distant vision
ciliary muscle relaxes causing a more flattened, more spherical/ circular lens
Nearsightedness
Myopia
- eyeball is too deep or resting curvature of lens is too great.
- lens tries to project image of a distant object to focal point more anterior than retina, so distant objects appear blurry.
- put a corrective lens on that will cause light to diverge before hitting the cornea to correct the problem
Focal point
is where all the light from all the angles are shining on one single point
farsightedness
Hyperopia
- eyeball is too shallow or lens is too flat
- lens can’t focus light enough when looking at close objects, so focal point would be behind the retina
- close objects are blurry.
- put a corrective lens that will cause light to converge before hitting the cornea to correct the problem
old man sight
presbyopia
- lens loses elasticity with age causing hyperopia
astigmatism
degree of curvature of the lens or cornea is off, so it can’t be refracted properly.
- can fix with lens or surgery
double vision
diplopia
- can be due to problems coordinating extrinsic eye muscles or other muscular or neurological problems
- you need a doctor to diagnose this;
strabismus
eyes aren’t aligned
- at least one eye is turned either too far inward (convergent) or too far outward (divergent)
- usually seen in kids
- treat with special glasses, patch strong eye, or surgery
color blindness
one or more classes of cones is missing or doesn’t work.
- most commonly the red cones are missing.
- this is x-lined , so men are much more likely to have it.
parts of external ear (4)
- Auricle
- external acoustic meatus
- ceruminous glands
- tympanic membrane
part of the ear we can touch and see
auricle
- channels sound into your external auditory meatus.
- allows or directional sensitivity for sound
ear canal
external acoustic meatus
- what you stick earplug into
- sends sound interior toward the tympanic membrane
-
What makes ear wax and what is its purpose
ceruminous glands
- helps keep foreign objects from getting into the ear
- slows microorganism growth
- reduces the likelihood of infection
eardrum
Tympanic membrane
- separates the external and middle ear
Middle ear
air filled chamber deep to the tympanic membrane
- gets air from connection with the nasopharynx and air cells in the mastoid process of the temporal bones of the skull
Parts of the middle ear (3)
- Eustacian tube (auditory tube)
- Auditory ossicles
- tensor tympani muscle
Eustacian tube
aka auditory tube
- the tube that connects the middle ear to the nasopharynx
- allows equalization of either side of the eardrum
auditory ossicles
3 tiny ear bones
- when sound vibrates the tympanic membrane, the tympanic membrane moves the bones causing the stapes to vibrate the oval window of the inner ear
Tensor tympani muscle
pulls on the malleus to keep it from vibrating too hard when you’re around loud noise, so that you don’t injure anything
Stapedius
keeps stapes from vibrating too hard when you’re around loud noise so that you don’t injure anything
Parts of the inner ear (9)
- Bony labyrinth
- Membranous labyrinth
- perilymph
- Endolymph
- vestibule
- semicircular canals
- cochlea
- oval window
- round window
Bony labyrinth
- area with receptors that give us our sense of equilibrium and hearing
- outer walls are fused with the surrounding temporal bone
- surrounds the membranous labyrinth
Membranous labyrinth
- collection of tubes and chambers that follows the contour of the bony labyrinth
- the organs of the inner ear have 2 layers fluid under each layer
- the membranous layer is the inner layer and contains the receptors for the organs
perilymph
the fluid between the bony labyrinth and the membranous labyrinth
endolymph
the fluid filling the tubes and chambers of the membranous labyrinth
three bones of the ear
Malleus
incus
stapes
vestibule
pair of sacs (saccule and utricle) that provides a sensation of linear gravity and acceleration
Semicircular canals
receptors stimulated by rotation of the head provide information about orientation of the head
cochlea
the snail shaped organ in the inner ear that turns sound into nerve impulses so you hear
oval window
what stapes vibrates to move sound vibrations to perilymph in the cochlea
- separates middle and inner ears
round window
one of two parts of the wall of the bony labyrinth that isn’t made of dense bone
- allows fluid in the cochlea to vibrate rather than shatter the back of the cochlea
what are receptors in the ear are called
hair cells
- that are connected to the dendrites of sensory neurons
- constantly secrete a small amount of neurotransmitter to the sensory neuron
Stereocilia
80-100 specialized microvilli on hair cells
- when stereocilia is distorted one direction it causes increased neurotransmitter secretion
- when it is distorted the other way secretion decreases
steps for the hearing process
1- sound waves arrive at the tympanic membrane
2- movement of the tympanic membrane moves the auditory ossicles
3- movement of the stapes at the oval window causes pressure waves at the top of the cochlea
4- pressure waves distort the basilar membrane
5- vibration of the basilar membrane causes hair cells to vibrate against the tectorial membrane
6- information about the region and intensity of stimulation is relayed to the CNS over the cochlear branch of CN 8
Frequency
Pitch of a sound wave is determined by which part of the cochlear duct is stimulated
amplitude
intensity/volume of a sound wave is determined by how many hair cells are stimulated
name two types of equilibrium
Dynamic equilibrium: helps maintain balance when the head and body are moved suddenly
static equilibrium: maintains posture and stability when body is motionless
Vestibule
deals with gravity and linear acceleration
otoliths
crystal that are attached to the stereocilia
- gravity pulling on the otoliths stimulates the stereocilia
semicircular canals
deal with rotational motion
- the stereocilia of the semicircular canals are embedded in gel, and are stimulated by endolymph pushing against that gel
3 canals in the semicircular canal
Anterior: senses up/down motion like nodding
Posterior: senses tilting motion
Lateral: horizontal rotation like shaking knead “no”,
Deafness
is partial or total hearing loss
types of deafness (2)
Conduction deafness
sensory (sensorineural) deafness
Conduction deafness
the problem with getting sound waves to the brain because the outer ear, tympanic membrane , or middle ear are blocked to broken
sensory deafness
the problem with getting sound waves to the brain because the inner ear, cochlea, or nerves are broken
