ELM 7.2

Question 1

olfactory receptor cells synapse onto second order olfactory neurons in specialized spherical structures in the olfactory bulb is called
buds
capsules
glomeruli
tracts

Answer 1

glomeruli
each glomerulus receives input from neurones expressing the same type of olfactory receptor
1200 glomeruli in young humans, but in ppl older than 80, they are almost completely absent

Question 2

a mechanism in olfactory cells that may amplify depolarization of the membrane involves
acetylcholine receptor activation
calcium-activated chloride channels opening
GABAB channel activation
voltage-gated potassium channels closing

Answer 2

calcium-activated chloride channels opening
when cyclic nucleotide gated channels open, they allow in calcium ions - the influx of calcium in turn activates calcium activated chloride channels
chloride ions then leave the cell, leading to increased depolarization

Question 3

which of the following is NOT a type of mechanoreceptor
jacobson’s organ
merkel cell
pacinian corpuscle
ruffini ending

Answer 3

jacobson’s organ
the jacobson’s organ is another name for the vomeronasal organ

Question 4

the cell bodies of the neurons that relay signals from cochlear hair cells to the CNS are located in which structure?
pacinian corpuscle
organ of corti
spiral ganglion
utricle

Answer 4

spiral ganglion
bipolar neurons and their cell bodies are located in the spiral ganglion - the utricle is part of the vestibular system, the pacinian corpuscle is a skin mechanoreceptor and the organ of corti is the receptor organ for sound

Question 5

which of the following is not a bone of the middle ear?
incus
malleus
stapes
tensor tympani

Answer 5

the tensor tympani is a muscle that contracts to protect the inner ear from damage by loud sounds

Question 6

what is the neurotransmitter released by cochlear hair cells?
acetylcholine
GABA
glutamate
noradrenaline

Answer 6

glutamate
glutamate is an excitatory transmitter and activates the spiral ganglion neurons that innervate the hair cells

Question 7

which crystaline substance is a key component of the vestibular system organs that detect head position
calcium carbonate
lithium carbonate
potassium carbonate
sodium carbonate

Answer 7

calcium carbonate
otolith organs use calcium carbonate (CaCO3) crystals to detect force of gravity and acceleration

Question 8

human olfactory receptors are ______

Answer 8

GPCRs

Question 9

odorant binding leads to the opening of a cyclic nucleotide-gated channel and _________ of olfactory receptor neurons

Answer 9

depolarization

Question 10

what are the 3 types of papillae?

Answer 10

circumvallate
foliate
fungiform

Question 11

what are the structures of the auditory system?

Answer 11

external ear
middle ear (bones: malleus, incus, stapes)
inner ear (chochlea)

Question 12

what are the structures of the vestibular system?

Answer 12

semicircular canals (posterior, horizontal, anterior)
otolith organs (utricle, saccule)

Question 13

_____ transduce sound into electrical signals. hair cells provide active ______, inner hair cells __________.

Answer 13

hair cells
amplification
send signal to the brain

Question 14

the properties of the basilar membrane means we have ______ representation f sound

Answer 14

tonotopic

Question 15

Otolith organs use calcium carbonate crystals to detect ______ and ______

Answer 15

force of gravity
acceleration

Question 16

semicircular canals detect _____

Answer 16

head rotation

Question 17

what is associated to steady pressure (skin indentation, texture discrimination)

Answer 17

merkel cells and ruffini endings

Question 18

what is associated with vibration?

Answer 18

meissner’s and pacinian corpuscles