Anatomy Exam 4: Special Senses

viterous humor and refraction

Leaves the lens and goes to the vitreous humor Changes again constant in their refraction

bitter, sweet and umami tastes use what kind of receptors

G protein linked cell receptors Indirect Bind to receptor that activates g protein which then opens different proteins to allow for depolarization

when we see red it is because

Red wavelengths are transmitted For something to have a color it absorbs all of the wavelengths except the color that it is, the color that it is (green grass) would have green wavelengths transmitted

the eyeball is

a highly specialized sensory organ

Focusing is accomplished by

accommodation of lenses constriction of pupils convergence of eyeballs

salavation role

aids in the breakdown of food

Order that light passes through the eye

air, cornea, aqueous humor, lens, vitreous humor, retina bends each time

photobleaching

loss of color by a pigment when illuminated when light is absorbed in the eye by receptors

olfactory receptor cells

main receptor cells sensory receptors that receive chemicals interpreted as smells

hyperopic eye (farsighted)

focal point is behind the retina corrected with a convex lens Far sighted eye Light is not converged onto the macula Point of convergence is outside the eye (doesn't happen)- behind eye Has not converged yet when it reaches macula Corrected by a convex lens in front of eye to bend it so that it all goes to macula

hearing involves

detection of sound waves or changes in air pressure unfolding over time uses the outer, middle and inner ear

types of eye related to focus

emmetropic (normal) Myopic (near sited) Hyperopic (far sighted)

gustatory cells of taste buds

epithelial taste receptor cells (sensory receptor cell) through their gustatory hairs they interact with chemicals

basal cells of taste buds

epithelial stem cells that divide and replace undifferentiate (can become gustatory or supporting) replace often and rapidly because of the harsh environment

filaments of olfactory nerve

make up the olfactory nerve olfactory nerves pass through cribriform plate and synapse at the hole of the skull with the olfactory bulbs

hair cells of maculae

mechanoreceptor cells that respond to movement receptor cells covered in otolitich membrane Jelly like substance that coats the sensory receptors, seperates them from endolymph and causes interia Sensory receptors = hair cells

perilymph

fluid contained in the labyrinth of the inner ear between bony and membranous labrynths

convergence of eyeballs

medial rotation of the eyeballs toward the object being viewed Eyeballs converge so they align on the object Finger moving toward middle of two eyes, eyes pivot and both focus on middle

oval window

membrane at the entrance to the cochlea through which the ossicles transmit vibrations connects stapes to inner ear

emmetropic eye

normal eye with light focused properly light converges on the retina All the light passes through and gets focused on macula of retina Retina has the photoreceptor cells that are going to use that light energy and transduce it into a nervous impulse

how is taste linked to emotion

sometimes side tracts go over to the hypothalamus and get linked to the limbic system emotional brain helps us determine what we like and don't like to eat

choroid

part of vascular tunic middle, vascular layer of the eye, between the retina and the sclera Just deep to the sclera Where all blood vessels are running through (nutrients and oxygen) and pass through choroid layer If you bring choroid to front, it modifies and adapts and become ciliary body

two types of photoreceptors and difference

rods and cones absorb different wavelengths of light pigments absob different wavelengths and then the wavelengths activate rids and cones

rods versus cones

rods: lots of them, operate under dim light, peripheral vision cones: less of these, operate under bright light conditions, give us visual activity

papillae and types of papillae

rough, bumpy elevations on dorsal surface of tongue fungiform and circumvallate

parts of middle ear

round window oval window pharyngotympanic tube auditory ossicles (malleus, incus, stapes)

Transmittance

the ability of light to pass through a medium, the light that goes through the eye that we see the only color that is not absorbed red roses don't absorb red color but rather the red is transmitted

what wavelengths make it to our eye

transmitted wavelengths

humors of the eye

chambers of the eye filled with a clear, slightly jelly-like substance fills so not hollow vitreous and aqeuous

supporting cells of taste buds

from the capsule surrounding the taste receptors cells, these cells support and protect there receptor cells Epithelial Most numerous (more of these than anything else)

gagging and vomiting role

gagging keeps us from swallowing something toxic preservation reflex vomiting happens if we swallowing something toxic it gets rid of it preservation reflex

what are the two senses associated with the ear

hearing and equilibrium (balance)

light that isn't absorbed is

transmitted

sensors involved in equilibrium

-Inner ear (vestibular apparatus which is semicircular canals and vestibule) -Eyes (harder to maintain balance with eyes closed) -Stretch Receptors (if there is more stretch on one side of the body than the other, we can tell which way we lean)

accommodation of lenses

-changing lens shape to increase refraction Lens is what focuses → lens changes its shape This is called the accommodation of lenses Ciliary muscles contract and change the stretch on suspensory ligaments which changes shape of lens Causes the light to be changed Lens is flat for far away things (lens is being stretch) Lens bulges for close up things (lens is being smushed together) Typically don't feel the extrinsic eye muscle because our eyes move so fast

Ganglion cells in the retina

-connect with bipolar cells All of the axons of the ganglion cells run together and exit back of eyeball as the optic nerve Optic disk is where they all exit and called blindspot because where all cells exit we have no sensory receptors

functions of taste

-trigger digestive reflexes (gets us ready to digest) -gagging -vomiting -salivation

round window

A membrane-covered opening in the inner wall of the middle ear that compensates for changes in cochlear pressure. allows pressure changes between middle ear and cochlea

what part of our brain is associated with vision

About half of cerebral cortex associated with vision

visual pathway to brain

Axons of retinal ganglion cells form optic nerve Medial fibers of optic nerve cross to opposite sides at optic chiasma lateral fibers stay on same side this allows for signals from both eyes to be sent to both sides of brain optic nerve continues as optic tract Most fibers of optic tracts continue to thalamus. Then to occipital lobes.

aqeous humor and refraction

After cornea enters the aqueous humor Enters the aqueous humor and gets bent as it changes shape again constant in their refraction

as chemical binds to the gustatory cell, the membraine

As chemicals bind, gustatory cell membrane depolarizes

activation of organ of corti

As the fluid (endolymph waves) moves past organ of corti, the organ of corti is now activated endolymph waves bends cochlear hair cells bending of hair cells in one direction opens cation channels causing depolarization if hair cells bend in other direction, the ion channels close causing repolarization or hyperpolarization depolarization causes an action potential to be created which increases release of neurotransmitter signal sent through spiral ganglion, to cochlear nerve to medulla, then midbrain and finally auditory cortex, also to thalamus then midbrain

Inner fiber of photoreceptor

Between cell body and synapse on axonial side of cell body both rods and cones have this (all photoreceptors)

bipolar cells of retina

Bipolar cells compose an intermediate layer of conncecting neurons in the retina interact with the photoreceptors in neural layer synapse with ganglion

visible light

Electromagnetic radiation that can be seen with the unaided eye very small range of wavelengths 400-700

cochlear nerve

Filaments of the cochlear hair cells merge together to form the cochlear nerve the branch of the auditory nerve that transmits auditory information from the cochlea to the brain

cataracts

Lens in eye becomes cloudy Usually not in children Prevents light from going through Reduces visual, clouds and blurs vision Accumulates with age Old not young Increased by cigarette smoking Increased by UV rays (no sunglasses) Prevent by increases vitamin c consumption

pigment

Light-absorbing molecule

most what we think of as taste is

Most of what we think of as taste is really smell With taste cannot differentiate cherry from orange Smell is what allows this

fungiform papillae

Mushroom-like protuberances often containing taste buds and located on the sides and tip of the tongue give grip when eating what we think of as taste buds

Outer fiber of photoreceptor

Part between the inner segment and cell body located on some photoreceptors (only on rods) extension of cell body and segments

lens of eye

Part we can adjust: allows us to focus Hard structure in eyeball Only part of the eye that can change its shape to allow focus Suspensory ligaments attach to the lens and allow us to change shape Biconvex flexible structure Goes out on both side Point of being flexible is that the light going through is focused on a very specific part of the eye Allows for focus

lens and refraction

Passes from the aqueous humor through the pupil to the lens Gets bent again as it goes to lens Lens is not constant (variable) → we can change the shape of the lens and by doing this we change its refractory abilities which changes how much the light bends Purpose of the lens→ biconvex, change its shape so that the light from all angles will go through the pupils and get projected to the retina (macula)

Stimulus: Light

Photons of light are the stimulus Photons are the unit of light energy

olfactory supporting cells

Provides metabolic and physical support and nurture and protect olfactory receptor cells mucosa cells most numerous

how are pigments broken down

Retinal detached from opsin → called bleaching of pigment cGMP destroyed Cyclic GMP is the secondary messenger so this closes the sodium gates Sodium gates close Generally (with chemoreceptor that is off), stimulus triggers sodium gate to open which turns on the chemoreceptor and causes depolarization In this case, the absorption of light closes the sodium gates normally sodium gates are open in photoreceptors which means that the photoreceptors are normally sending signals to the brain and when light gets to it it closes the gates

rotation of head

Rotation affects each side of head differently If i rotate head to the left, the right ear has had to move much more than the left Crista ampulla of the right ear are having more endolymph movement that the left ear Allows brain to determine which direction we are moving Rotation on 3 axis This is due to semicircular canals are located in 3 planes

what is adaptation in taste

Sensory receptors associated with taste adapt rapidly Adaptation is continue to be stimulated but no longer respond lose sense of taste because taste bud adapts

extrinsic eye muscles

Six muscles attach to the outer surface of the eye and produce eye movements hold eyeball so that it can focus on something Pulls eyeball different ways to shift and to focus on certain directions How our eye moves When functioning normally, eye is held in place

process of hearing

Sounds set up vibrations in air Vibrations in air (sound waves are the vibrations) Sound waves are channeled and focused through the external auditory canal to get to the tympanic membrane Tympanic membrane vibrates due to the sound waves (frequency of vibration= frequency of sound wave) As the membrane vibrates, the vibrations are transferred to bones of middle ear tympanic membrane pulls on malleus, malleus bounces off incus and incus bounces on stapes stapes pulls against oval window and endolymph is on the other side of the oval window and presses endolymph of inner ear which causes waves in fluid Waves in the endolymph move the fluid and it passes by organ of corti Force of fluids activates the organ of corti neurons in the organ of corti are stimulated and generate an action potential which is sent to brain This causes action potentials to be created and then signal is sent to brain

taste buds

Special sensory organs modified to detect different chemicals, contain the receptors for taste found in the mucosal papillae of the tongue, also found on the soft palate, cheeks, pharynx and epiglottis

tympanic membrane

The eardrum. A structure that separates the outer ear from the middle ear and vibrates in response to sound waves. thin membrane at bottom of canal

refraction

The bending of a wave as it passes at an angle from one medium to another light can be bent Photons travel at constant speed in any medium When change from one medium to another, they change the speed that they travel at which bends the light Example Light is passing through air, travels at the same speed all through the air When it hits the glass, the glass slows it down When it passes through glass and enters water, speeds back up This causes the light to bend → causes refraction

Reflection

The bouncing back of a wave when it hits a surface through which it cannot pass. light can reflect, it can bounce off of a surface Reflection is not transmittance

Conjunctiva function

Transparent mucous membrane that lines eyelids and covers the eye Secretes mucus to lubricate the eye creates conjunctival sac that is part of a fluid that lubricates and moistens eye prevent particles from getting trapped behind the eye

white and black color

White does not absorb any wavelengths, black absorbs all wavelengths Everything transmitted in white, nothing transmitted in black

cochlea

a coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses full of endolymph cochlear duct which is coiled and divided into scala (chambers) organ of corti which is the receptor for hearing

vestibule

a small entryway saccule: portion closest to cochlea utricle: portion closest to semicircular canals maculae: equilibrium receptors located in saccule and utricle

olfactory epithelium

a thin layer of tissue, within the nasal cavity that is located in the mucosa at the roof of the nasal cavity mucosa is a mucous membrane that secretes fluids the olfactory epithelium contains the receptors for smell

synaptic ending of photoreceptors

allows for synapse with bipolar cells Synaptic portion synapses with the bipolar cell layer of retina which then synapse with the ganglion cells which then carry the message through the optic nerve to the brain

pinna

auricle, or outer ear composed of cartilagenous tissue catch sound waves and bend them to auditory canal helix which is upper edge lobule which is fleshy part/lobe

how people taste things is determined by

can you detect it? (if there are receptors or not) how many receptors you have cultural

parts of inner ear

bony labyrinth and membranous labyrinth

layers of inner ear

bony labyrinth, perilymph, membranous labyrinth, endolymph (from outer to inner)

vascular tunic of the eye

called uvea middle layer, deep to fibrous tunic choroid, ciliary body, iris

pharyngotympanic tube

canal that connects middle ear with throat (pharynx) equalizes pressure in middle ear to atmospheric pressure Pressure in the middle ear has to be equalized to atmospheric pressure so the middle ear must be connected to the external environment If pressure is too high in the middle ear then the tympanic membrane cannot bounce and will bulge Inner ear infection; very painful

Parts of photoreceptors

cell body outer segment inner segment outer fiber inner fiber synaptic ending photodiscs pigment

chemical senses rely on

chemo receptors chemo receptors transduce chemical energy into an action potential

Olfaction uses which type of receptors?

chemoreceptors

inner segment of photoreceptors

contains metabolic machinery of cell closer to the cell body on dendritic site connected to outer segment

photoreceptors of retina

convert light energy into electrical signals light energy is transduced into action potentials Rods and cones Synapses with bipolar cells

Receptor for equilibrium

crista ampullaris is the ampulla at the ends of semicircular canals

outer segment of photoreceptors

detects light stimulus furthest from cell body, closest to pigmented epithelium photopigments are stacked in discs here -- photodiscs Different photopigments respond to different wavelengths of light Inside of the photopigment disks, combination of vitamin A product (retinal) and embedded in retinol is a protein (opsin is protein) Opsin and retinal can combine and generally make 4 separate photopigments

different gustatory cells have...

different thresholds for activation because they have different chemicals that they sense

salty and sour tastes use what kind of receptors

direct Channel linked receptors Chemical binds and immediately opens channel to allow depolarization to occur

each olfactory receptor is specific to __________ ___________ and have different ___________

each olfactory receptor is specific to a different chemical and have different thresholds

what is the sense organ for vision? how many sensory receptors are in the sense organ?

eye 70% of sensory receptors are in eyeballs

accessory structures of the eye

eyebrows, eyelids/eyelashes, conjunctiva, lacrimal apparatus, extrinsic eye muscles

activation of photoreceptors

eyes constantly send signals to brain when light is absorbed, shuts off certain signals receptors and stops sending signals to the brian brain decodes lack of signal as something important can detect what color because pigments that are absrobaed are the one that are bleached out

aqeous humor

fills the anterior and posterior chambers of the eye, supports, nourishes, and removes wastes for the cornea, Anterior chamber in front of the lens under the cornea Watery Continuously gets replaced and renovated

steps of smell

gaseous molecules enter nasal cavity when we breath gas molecules dissolve in epithelial mucous and become active (turn into a solution) dissolved chemicals bind to receptor molecules on olfactory cilia receptor potential is generated if it gets above the threshold we get an action potential action potential is transferred through the filaments synapses with olfactory bulbs at glomeruli action potential is sent to the CNS by the olfactory tracts goes to cerebral cortex so we percive we smelled something

digets reflexes role

get our body ready to digest meal stimulates salivation and gastric juice parasympathetic response

What are the two chemical senses?

gustation (taste) and olfaction (smell)

how often do gustatory and supporting cells get replaced

gustatory and supporting cells get replaced every 7-10 days EX: Burn your tongue on something hot, you lose your sense of taste for a little while but it comes back relatively quickly because the basal cells are constantly dividing to replace those things.

components of taste bud

gustatory cells, gustatory hairs, supporting cells, taste pore, basal cells

olfactory cilia

hairlike structures located in upper portion of nasal passages come off of the ends olfactory receptor cells dendritic portion that synapses with olfactory nerve to pull in smell covered in mucus

chemicals in food must be in a

in a solution, so that the liquid can bind to the hairs

steps of taste

ingest something chemical dissolves in saliva to become biologically active and become solution chemical solution binds to gustatory hairs when chemicals bind the gustatory cell membrane depolarizes for salty and sour, the chemicals bind directly, channel linked receptors where the chemical binds and immediately opens channel to allow for depolarization for bitter, sweet and umami, the chemicals bind indirectly and use g protiein linked cell receptors where the chemicals bind to receptor that actovates g protein which opens different proteins for activation generator potential is created If we get to action potential from generator potential, a neurotransmitter is released from synapse of sensory neuron Action potentials sent to CNS through cranial nerves

equilibrium involves

inner ear

Vitreous humor

jellylike substance found behind the lens in the posterior cavity of the eye that maintains its shape Stuff behind the eye between the lens and the retina Created as an embryo and lasts forever Posterior segment is separated from the anterior segment by the lens and suspensory ligaments so everything in the posterior segment is the vitreous humor Maintains intraocular pressure which maintains shape of the eyeball Thick like snot

circumvallate papillae

large papillae with taste buds on the very back of tongue only have 7-12

light moves in ______ and is a form of ______ _________

light Travels in waves and Light is a form of electromagnetic radiation

define focus of eye

light beams converge on certain part of retina and when they converge in the right place our vision is focused if they dont converge at the macula of the retina vision is blurry

steps of sensing light

light comes in from front of eyeballs and passes through ganglion cell, bipolar and photoreceptor layers but can't interact yet because has no pigment light first interacts with the pigmented layer then passed back through photoreceptor then bipolar then ganglion when reaches ganglion cell layer, axons of ganglion cells combine to form optic nerve optic nerve wraps back around and carries signal out of the back of the eyeball to the brain

light is absorbed at the ____ layer and forms a signal at the _________

light is absorbed at the back of the eyeball at the pigmented layer and then forms signal at the inner segment of the photoreceptor layer and then goes to brain

membranous labyrinth

lining the tunnels inside the bony labryth contains endolymph

midbrain and vision

midbrain is visual reflex center and coordinates movement of eyes by extrinsic eye muscles

response of crista to inertia

movement of endolymph deforms crista increases or decreases release of neurotransmitter depending on the direction that the hairs are bent causing either hyperpolarization or depolarization causes change in rate of impulses to the brain

responses of maculae to inertia

movement of otolithic membrane bends hairs increases or decreases release of neurotransmitter depends on which way the hairs are bent causing depolarization or hyper polarization causes change in rate of impulses to the brain ex- even if you aren't moving but you are on an elevator, you can feel your head move b/c it is changing positions in space (static equilibrium) We are constantly monitoring equilibrium so we are constantly sending signals so the change in rate of the signals Speeding up or slowing down the rate of signals Allows us to maintain normal head position with response to gravity

myopic eye

nearsighted- focal point is in front of the retina The way the light gets bent by this eyeball has all of the light converging at a spot that's in front of the macula By the time it reaches macula, it has gone out of convergence and gotten fuzzy again Gets corrected with a concave lens either in glasses or contacts Puts extra bend in there to make the light for to the right place

cells associated with smell

olfactory receptor cells supporting cells basal cells olfactory cilia filaments of olfactory nerve

taste pore of taste bud

opening at the top of the papillae (opening in taste bud) allow gustatory hairs to exit taste bud, they stick out of the pore

receptor for hearing

organ of corti

Parts of the Organ of Corti

organ of corti is in the middle of the cochlea, sensory receptor for hearing Supporting cells Cochlear hair cells Cochlear nerve

fibrous tunic of the eye

outer layer around the eye sclera and cornea protects eyeball and defines shape sclera: White opaque part of eye Goes from the front of the eye all the way around, outer layer all around the eye cornea: Clear part right over the center of the eye, transparent

tongue is covered in

papillae

pigmented layer of retina

part of sensory tunic Outermost layer of the retina (just inside of choroid) Thin layer of pigmented epithelium tissue Pigment is any chemical or structure that can absorb light (has light absorbing properties) absorbs light and prevents it from scattering in the eye

neural layer of retina

part of sensory tunic (retina) houses photoreceptors and other associated neurons divided into layers ganglion cells, bipolar cells and photoreceptors

cilliary body

part of vascular tunic (uvea) It originates from the choroid in the back of the eye Ciliary body is in the front of the eye below the iris A bunch of muscles and attachments that attach to the lens of the eye This is how we change the shape of the lens, the pulling/contraction of the lens by the pulling of the ciliary body (either can flatten it or bulge it)

iris

part of vascular tunic (uvea) a ring of muscle tissue that forms the colored/pigmented portion of the eye around the pupil and controls the size of the pupil opening

pupil

part of vascular tunic (uvea) also part of iris Where light passes through and muscles can change the diameter of the hole to regulate how much light can pass through

Order of how sound travels through the ear

pinna --> ear canal --> eardrum --> ossicles (hammer, anvil, stirrup) --> oval window --> cochlea --> cochlear fluid --> cilia --> organ of Corti

parts of the outer ear

pinna, auditory canal, tympanic membrane (ear drum)

how do we differentiate sounds

pitch: certain pitches activate certain hair cells (hair cells are not the same and respond to different pitches) and pitch is determined by which hair cells are activated loundness: based on number of hair cells activated direction: nerve impulses coming to ear located closer to sound arrive sooner than the other side which allows us to detect which side the sound comes from

properties of sound include

pitch: frequency of waves (number of waves per second), determines pitch, high frequency means high pitch loudness: volume, determined by ampliture of the wave, higher waves have a higher volume

gustatory hair

projects from each gustatory receptor cell to the external surface through the taste pore dendritic portion of sensory cell (receptive field of chemical), interacts with chemicals to create a generator potential

Eyelids function

protect the eyes and spread lacrimal fluid (tears) with blinking - shade the eyes during sleep - protect the eyes from excessive light and foreign objects - and spread lubricating secretions over the eyeballs

light properties

reflection and refraction

constriction of pupil

regulates amount of light going into eyes By constricting pupil we limit the amount of light that comes through Prevents divergent rays Rays that are coming from harsh angels that would not be able to be focused at macula are eliminated by constricting the pupil Under low light conditions pupils are not constricted Pupils open allow us to see in low light

crista ampullaris

respond to dynamic equilibrium in the ampulla of semicircular canal just endolymph in crista ampullaris the Cupula contains the hair and supporting cells hair cells are sensory receptors

sensory tunic

retina most inner layer Started out as an outpocket of the brain and separated from the brain and moved into the eye Highly neural sensory portion of eyeball Between the humor (fluid) and choroid pigmented layer, neural layer, photoreceptor, bipolar cells and ganglion cells

all sensory information is sent to

sensory inputs all go to the thalamus

the sensory receptors of special senses are called

sensory organs

maculae

sensory receptors for static equilibrium (part of vestibular apparatus) in saccule and utricle Macula in utricle are horizontal Hairs are vertical Detects horizontal movements → side to side Maculae in the saccule are vertical Hairs are horizontal Detects vertical movements

Cochlear hair cells

serve as sound receptors in the basilar membrane Receptor cells The hair cells are the free portion and are up in the endolymph have inner and outer

parts of the eye linked to refraction

several parts of the eye are linked to the bending of light energy Cornea, humors, lens Some are constant, some of them vary

Eyebrows function

shade eye from sunlight, prevent perspiration from reaching eye

smell and taste receptors are generally _____ photoreceptors are usually _______

smell and taste receptors are always off until turned on by a chemical photoreceptors are on (constantly sending signals) and then when light is absobred it turns off

special senses

smell, taste, vision, hearing, equilibrium/balance

Glomureli

spherical structure in olfactory bulb where synapses form between terminals of the olfactory nerve and the dendrites of mitral periglomula and tufted cells

photodiscs of photoreceptors

stacks of photopigments made up of two proteins retinal derived from vitamin A opsin combine to form retinal opsin complex combine in 4 different petterns result in 4 different light absobing pigments

The two types of equilibrium are

static (maculae) dynamic (crista ampullaris)

olfactory basal cells

stem cells that replace olfactory receptors divide and replace supporting and receptor cells replace at a high rate but slower than tongue

5 tastes and description

sweet: sugars and alcohols, high calorie food, stimulates more consumption (excitatory) sour: produced by acids (citric acid and vinegars), shuts off further consumption (reduces eating) salty: produced by potassium and sodium ions (metal ions) , craved by people with electrolyte deficiencies , stimulates consumption bitter: serves as a warning to not ingest poisonous or spoiled food, produced by organic alkaloids like caffeine, provokes facial expressions, shuts off consumption umami: produced by amino acids (glutamate), perceived as a meaty flavor, flavor enhancer, in between shut off and stimulate

functions of smell

sympathetic activity: elicits fight or flight (get away; skunk) parasympathetic activity: activates digestive reflexes (salavation) sneezing/choking: tries to get ride of chemical, forcefully push to get it out, both are preservations reflexes

CNS destinations for smell

thalamus to olfactory cortex thalamus takes the signal and sends it to olfactory cortex olfactory cortex interprets and identifies the smell become consciously aware of a smell hypothalamus to amygdala Amygdala is part of limbic system and limbic system is emotional brain hypothalamus to the amygdala to the limbic system which elicits an emotional response to oder

olfactory bulb

the first brain structure to pick up smell information from the nose nerves go here and synapse and when synapsed the bulbs carry/take the signal to the brain

optic nerve

the nerve that carries neural impulses from the eye to the brain ganglion cells make up the optic nerve and optic nerve exits the back of eyeball Optic nerve carries action potential (carries the signal) to the brain

optic chiasm

the point in the brain where the visual field information from each eye "crosses over" to the appropriate side of the brain for processing this allows for signals from both eyes to be sent to both sides of brain

lacrimal apparatus

the structures that produce, store, and remove tears provides other fluid to protect eye Glands located in the lateral corner of eye that secretes a fluid and washes across surface of eye Gets drained through the lacrimal ducts which connects into passage way that empties out into our nasal cavity If eyes are moist and watery our nose is going to run This is due to the lacrimal apparatus connecting eyes and nose

all of the special senses have sensory receptors that are

they all have unique sensory receptors that are located in the head

semicircular canals

three canals within the inner ear that contain specialized receptor cells that generate nerve impulses with body movement full of endolymph anterior (vertical) posterior (diagnol) and lateral (horizontal) ampulla: rounded swelled end of each canal, within each ampulla are equilibrium receptors call crista ampullaris

auditory ossicles

three small bones linked together that connect the eardrum to the inner ear

how does the action potential travel through CNS

through cranial nerves First to solitary nucleus in medulla then to thalamus to gustatory cortex (sensory portion of cerebrum) and only NOW do we perceive we tasted something Have no perception that we tasted something until it gets to gustatory cortex

The Optic Tract carries signal

to thalamus then primary visual cortex All sensory information comes to thalamus Once it leaves thalamus will go to the primary visual cortex Primary visual cortex allows us to have conscious perception that we are seeing something or midbrain to superior colliculi Don't give us conscious perception Visual reflex center= Superior colliculus Superior colliculus controls the extrinsic eye muscles Eyes tend to move toward visual stuff even though we aren't consciously aware

external auditory canal

transmits sound waves from the pinna to the tympanic membrane of the middle ear tunnel that directs sound to middle ear

shape of eyeball is due to

tunics

eyelashes function

type of filtration Dust from air, blink a lot and eyelashes catch the particles and prevent them from going into eyes Have root hair plexus → nerve endings connected to base of hairs Protective mechanism→ when touched, we want to blink

we have no perception we tasted something until

until it gets to gustatory cortex in the cerebrum

The image projected on the retina is

upside down and reversed from left to right (upside down and backwards) brain decodes

how does an eyeball bend light

various parts of the eye refract the light causing it to bend Light needs to get bent so it can go to the macula of the retina Light brought in from all angles and projected here by using refraction

parts of bony labyrinth

vestibule, semicircular canals, cochlea

steps of activation of photoreceptors

visual pigments absorb the light (photo bleaching) light triggers break down of pigment retinal breaks apart form opsin (retinal opsin complex broken) cGMP is the secondary messanger and is destoryed and sodium gates close photoreceptors hyperpolarize release of neurotransmitters is inhibted no more action potentials are sent to the brain called light activation

what are tunics and what are their names

wall layers of eye 3 layers fibrous, vascular and sensory

sound travels in

waves

cornea and refraction

where the greatest amount of refraction occur as light enters it Light travels through air and reaches cornea first (air to cornea) Cornea changes speed of light so it gets bent constant in their refraction

do taste sensory receptors adapt

yes they adapt rapidly