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321 EAR SLIDES

Terms in this set (58)

Ear is the auditory and balance center for our body and job is to collect _____ ____ via ____ and ____?
sounds waves via pinna and external auditory meatus. outer ear.
outer ear is made up of?
Pinna and External auditory meatus.
Middle ear's job is to?
Amplify (amplication) of sound waves
Middle ear made up of four parts?
1. Tympanic membrane (ear drum)

2. Ossicles - maleus, incus and stapes (little bones)

3. oval window

4. round window
Inner ear's job?
transduction of sound waves into signal brain can detect via:

cochlea and vestibular apparatus
eustachian tube's job?
Equilibrate pressure.

Also known as auditory tube that runs to throat. when we get cold it backs up
Pinna
...
External auditory meatus also called
ear canal. connects external environment to the beginning of middle ear or eardrum.
purpose of Cochlea?
transmission of soundwaves into an electrical signal to the brain
semi-circular canals are for?
balance.
Auditory tube
goes to pharynx which goes to throat. This is the reason babies get ear infections. it is short and horizontal.
start last lecture for this exam - bare minimum
for eye know g protein receptors, rods and cones, structure of the eye and how light passes through.

ears structure sound waves go through, cochlea etc.
pathway for sound waves
stars in external auditory meatus and travels to tympanic membrane. hits membranes and makes them vibrate, ossicles vibrate and that makes oval window vibrate.
outer ears job is to?
direct the sound waves.
lower and higher the pitch?
lower the frequency starting in the tympanic membrane.

Lower soundwaves make lower vibrations and higher soundwaves make higher vibrations.

amplifying the sound of the vesicles
when does the soundwave become a chemical signal?
Inner ear - changes soundwave to a chemical signal
Sound Amplification in the Middle Ear

1. Sound waves strike?

2. which Causes movement of?

3. which Causes movement of?
1. tympanic membrane

2. ossicles (lever system) - First level of amplification

3. oval window
Second level of amplification
Oval window smaller than tympanic membrane
hair cells have?
stereocilia and are receptors.
when hair cells move?
they open mechanically gated channels which allow for activation for action potentials.
Fluids of the Cochlea

two parts
Perilymph

Endolymph
Endolymph has a High concentration of?
K+

also Scala media
Perilymph 2 parts?
1. Scala vestibuli

2. Scala tympani
Hair Cells of the Organ of Corti

need to know!!!
hair cells are the receptor for sound. And have stereocilia and are surrounded Endolymph.
Inner Hair Cells: Sound Conduction pathway?
when we start sound waves are vibrating depending on pitch or frequncy of sound wave. All vibrates till we hit oval window. At that point, _____ go to stereocilia then fire AP.

mechanically gated channels
Mechanism of Sound Transduction

Stereocilia of hair cells connected by?
- protein bridges
Mechanism of Sound Transduction cont'd

1. when you bend tall stereocilia you?

2. when you bend short stereocilia you?
Mechanical stress moves protein bridges opening or closing cation channels:

1. depolarization

2. hyperpolarization
Intensity coding =

Frequency coding =
loudness

pitch

low frequency means lower wave and lower pitch.
once you activate receptors you activate?
cranial nerve (Cochlear nerve). then goes to brain stem where it will synapse to second order neuron's to auditory center of our brain.
Neural Pathways for Sound
Second-order neuron goes to the to thalamus

Thalamus is a relay center
Conductive deafness
damage to middle ear.
Inadequate conduction of sound waves through external and/or middle ear
Sensorineural deafness
damage to Inner Ear.
Inadequate transduction of sound waves to electrical signals in inner ear
Central deafness
(damage to the brain)
Damage to the neural pathway for sound
balance aka Equilibrium
Anatomy of the vestibular apparatus these are

The semicircular canals and the transduction of rotation

The utricle and saccule and the transduction of linear acceleration

Neural pathways for equilibrium
3 semicircular canals detect movement of the head?
1. Anterior canal

2. Posterior canal

3. Lateral Canal

- Cranial Nerve VIII
a. Vestibular nerve for equilibrium
b. Cochlear nerve for hearing
- Vestibulocochlear Nerve
Utricle and saccule purpose?
to detect linear Acceleration

hair cell still receptor.
otoliths
pieces of bone who's purpose is to sit on top of a jelly like layer and when you move, they move in the opposite direction.
Utricle and saccule summation for exam to know?
linear acceloration that use hair cells with Otoliths.
we coordinate our movements at the?
cerebellum
Taste and Smell

taste is called?

smell is called?
gustation

olfaction

both use chemoreceptors and respond to chemicals.
gustation and olfaction both use _____ and respond to ______
chemoreceptors
chemicals.

both use chemoreceptors and respond to chemicals.
what are the only neurons that regenerate in our body?
Olfactory receptor cells.

Olfactory receptor cells are unique in that they are one of the few neuron types that undergo turnover throughout adult life.
Taste and Smell directly from slide
The receptors for taste (gustation) and smell (olfaction) are chemoreceptors and respond to chemicals.

Olfactory receptor cells are unique in that they are one of the few neuron types that undergo turnover throughout adult life.
taste buds are the primary sensory receptor
found tongue, cheeks, rough of the mouth
...
Over 10,000 taste buds
Tongue
Roof of mouth
Pharynx

Pore exposed to saliva in mouth

50-150 taste receptors cells per bud
Modified epithelial cells
Respond to tastants

- support cells
There are 5 basic taste qualities:
Bitter, sweet, sour, salty and umami.

- umami means delicious
these are the triggers for taste
Umami is produced by the amino acids glutamate and aspartate. gives beef flavor and Cheese tang and MSG.

- Sour
Due to H+

- Salty
Due to Na+

- Sweet
Due to ligands

- Bitter
Due to ligands
sour and salty
sour
H comes, on a normal cell, K channels open, open voltage gated calcium channel and release NT.

salty
open a Na channel, then depolarize and open a voltage gated calcium channel and release a NT
sweet
is a g protein so we'll use a ligand. it's going to make gustducin (g protein). Activate cAMP for sweet.

Bitter
start with ligand gated ion channel or transducin (g protein) for ligand receptor. If transducin we use PLC (phospholipase C).
Coding of Taste
- Each taste receptor cell responds to all four primary tastes
a. Generally respond to one more strongly than others

- Different types of receptor cells located within a taste bud
a. Some differential distribution

- Coding of taste complex
a. Pattern theory
b. Requires sense of smell

MUST HAVE SENSE OF SMELL IN ORDER TO TASTE

STRONGER THE SMELL STRONGER THE TASTE
Neural Pathway for Taste
Sensory neurons alternate in brainstem. = CN VII, IX, and X

Terminate in brainstem gustatory nucleus and go through thalamus.

Second-order neurons to thalamus
Olfaction depends on?
Olfaction depends on chemicals in air binding to chemoreceptors that pick up on chemicals in the air.

Olfaction depends on chemicals in air binding to chemoreceptors in olfactory epithelium

1. Anatomy of the olfactory system
2. Olfactory signal transduction
3. Neural pathway for olfaction
basal cells are?
stem cells who's job is to make more neurons

- only regenerative neurons in our body. KNOW THIS!

Axons go through cranial cavity into our brain
olfactory glands make?
mucus
glomeruli means
glow
Olfactory Epithelium

Three cell types
1. Supporting cells
- Secrete mucus

2. Basal cells
- Precursor cells for new receptor cells (STEM CELLS)

3. Receptor cells
- Neurons that respond to odorants
purpose of mucus layer is to?

Olfactory Receptor Cells

main point to know!
dissolve the chemical

these are chemoreceptors

Only neurons replaced continuously
...
air-borne chemical

Activates G protein called Golf
Activates adenylate cyclase cAMP
cAMP directly binds cation channels, opening them
Na+ and Ca2+ enter cell depolarization
know g proteins that go with each receptor type?
- transducin for bitter

- Gustducin - for sweet

receptor Golf

No oly neuron does not go back through thalamus.
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