Lecture 28 Flashcards
What is hearing?
sound waves converted to electrical energy in hair cells
What is equilibrium?
detection of body position using the semicircular canals
What is the pinna?
collects and directs sound waves into the ear
How small is the ear canal?
very small
What is the tympanic membrane?
eardrum
What are the 3 tiny bones right after the tympanic membrane that passes the vibrations to the vestibular apparatus?
incus | stapes | malleus
Which section of the ear (inner, outer, middle) is fluid filled?
inner
What are the 2 main parts of the inner ear that translates the vibrations from the sound into info for the CNS?
vestibular apparatus | cochlea
What does the vestibular apparatus do with the vibrations it receives from the 3 tiny bones?
translates the air vibrations into fluid-filled vibrations = send signal to different parts of the cochlea
What does the cochlea do with the vibrations it receives from the vestibular apparatus?
has tiny hair cells each can detect a different frequency of sound
What is the cochlea?
intricate device that can detect different wavelengths of sound
What are the nerves that the cochlea sends the sound info to?
auditory nerves
What is the sound info coded as?
neurotransmitter release
What are semicircular canals and which section of the ear are they located?
bones help detect position | positioned in the X, Y, Z axis | found in the inner ear
How many Hz can ears detect?
20,000
How can the auditory cortex distinguish the different frequency sound waves?
hair cells active at basal/baseline level = auditory cortex compares the incoming signal from the basal activity
Where in the cochlea are the hair cells located?
cochlear duct
What is the tympanic duct?
where the sound leaves through the round window
Where are hair cells that detect higher frequencies located along the cochlear duct?
closer to the ear opening
What happens when a sound wave triggers a hair cell?
hair cells move in one direction »_space;> ion channels open »_space;> depolarization of hair cell »_space;> NT release
What does the semicircular canals tell us?
orientation of the head in space
What are otolith crystals?
attached to the membrane | goes where gravitational pull is the highest = signals CNS where the head is going
What are otolith organs?
have otolith crystals | macula
What are the 2 otolith organs?
utricle | saccule
What is vertigo?
when the otolith crystals are dislodged »_space;> causing confusion in the CNS not knowing where your head in space is
What are cristae?
responsible for acceleration movement | at openings of semicircular canals | has hair cells
What are the 2 branches of Cranial Nerve VIII?
vestibular branch and cochlear branch
What type of receptors are smell and taste?
chemoreceptors
What are the 2 oldest senses in organisms?
smell and taste
What is the olfactory bulb?
extension of the forebrain
What are the olfactory sensory neurons?
primary sensory neurons of the olfactory system
What is the only special sense that does not need to pass through the thalamus?
olfactory = goes directly to the olfactory cortex (in front of brain)
How are different and new smells and flavors encoded to the CNS?
different combos of different molecules = can trigger different combos of neurons »_space;> send the info together to get combo of different inputs
What is Cranial Nerve I?
the bundle of olfactory nerve axons
How can taste and smell trigger associated memories?
these senses are not memorized but can be recognized and associated with a memory
Where are the odorant receptors located?
at the olfactory cilia (dendrites)
What is the function of the Bowman’s gland?
secrete mucus to protect the nerve endings so the cilia can stay moist
What are the 3 things that the olfactory neurons connect to?
olfactory bulb | cilia | mucus gland
What is gustation?
sense of taste
What are the 5 types of taste?
sweet | sour | salty | bitter | umami
What is umami?
taste for amino acids
What activates the gustatory neurons?
chemical signals from taste receptors
What cranial nerves do the gustatory neurons become?
7, 9, 10
Which taste receptors are ion channels?
sour and salty
Which taste receptors are G-coupled receptors?
sweet | umami | bitter
How can neighboring taste receptors trigger each other?
ATP can act as NTs = activate primary sensory neurons or activate neighboring cell types to release more NTs
What is taste transduction?
each taste cell senses only one type of ligand
What are transient receptor potential (TRP) receptors?
taste receptor activated based on temperature (ie: mint and cold water)
What are the 4 non-traditional taste sensations?
fat | CO2 | calcium | capsaicin
