Ch. 7 Taste, Smell, Mechano (Book) Flashcards Preview

Animal Physiology > Ch. 7 Taste, Smell, Mechano (Book) > Flashcards

Flashcards in Ch. 7 Taste, Smell, Mechano (Book) Deck (62)
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1
Q

chemoreceptors are specialized for info about the… and 2 types

A

chemical envir and transmitting it to neurons

gustatory (taste) receptors

olfactory receptors

2
Q

airborne molecules first pass through a layer of _______ _______ before they reach olfactory receptors

A

aqueous solution

3
Q

sensilla/sensillum

A

hollow hairlike projections with a pore that allows stimulant molecules to reach sensory cells

4
Q

taste in a housefly

A

on its proboscis or feet each sensillum has dendrites from many receptor cells

each is sensitive to a different chemical stimulus

5
Q

will chemical stimulation of just a single sensillum of a fly provoke a behavioral response?

A

yes, it will lower its proboscis to feed

6
Q

where are taste receptors found in terrestrial vertebrates?

A

tongue

epiglottis

back of the mouth

pharynx/upper esophagus

7
Q

taste receptors in vertebrates are grouped into _____ ___ surrounded by ____ ____

A

taste buds, basal cells

8
Q

basal cells

A

surround taste buds and are progenitor cells that give rise to new taste receptors (they die in ~10 days)

9
Q

5 taste qualities

A

sweet

salt

sout

bitter

umami (MSG)

10
Q

evolution of taste qualities

A

sweet - rich in calories

salt - maintain water balance

sour/bitter - toxic/danger

11
Q

salty mechanism

A

salty tastants like NaCl dissociates in water

Na enters receptors through a special Na channel that is always open in the apical memb (blocked by amiloride)

depolarizes cell

12
Q

sour mechanism

A

H+ ions enter amiloride-sensitive Na channels of apical memb

Block K+ channels

depolarizes cell

13
Q

sweet mechanism

A

alanine binds receptors that use a G protein to start a cascade that ends in the closing of K channels

14
Q

bitter mechanism

A

quinine blocks K channels in apical memb

small resting Na current depolarizes the cell

15
Q

bitter mechanism under study

A

quinine binding activates G protein gustducin

actives phospholipase C which increases IP3 to release Ca

16
Q

do vertebrate taste receptors make APs?

A

yes, but don’t have axons

synapse onto neurons whose axons run into the facial, glossopharyngeal, and vagus nerves

17
Q

labeled line coding

A

receptors connected to a specific set of axons

18
Q

olfactory receptors in vertebrates

A

found in the nasal cavity (line turbinates)

arranged so a stream of air or water flows over them during ventilation

19
Q

vomeronasal organ

A

olfactory chamber that mediates chemical communication btw animals of the same species

for pheremones

20
Q

each receptor in the main olfactory epithelium has a long, thin _______ that terminates in a small ____ at the _____. what is found on the knobs

A

dendrite, knob, surface

thin cilia covered in the protein soln mucus

21
Q

only _______ olfactory neruons respond to odors

A

ciliated

22
Q

nasal olfactory transduction cascade

A

G protein activates adenylyl cyclase that increases intracellular cAMP

cAMP opens cation-selective channels –> depolarization

23
Q

APs from olfactory receptor axons carry the signal where

A

olfactory bulb of the brain

24
Q

glomeruli

A

spherical clusters of neurons

ex. olfactory bulbs of insects and invertebrates/vertebrates

25
Q

what kind of stimulus activates mechanoreceptors

A

a stretch or distortion of plasma membrane

uses ion channels

26
Q

sensory bristle

A

found of the surface of insects

a stiff hair associated with a single bipolar sensory neuron

27
Q

endolymph

A

fluid with a high [K+] that bathes dendrites of sensory bristles

28
Q

what happens when an insect sensory bristle is moved

A

the dendrite is deformed and stretch-actived cation-selective channels are opened

K+ flows in (unusual) instead of out, which depolarizes cell

29
Q

hair cells of vertebrates

A

extremely sensitive mechanoreceptors

many cilia from the apical end of each cell

coupled by kinocilium to accessory structures

30
Q

2 classes of hair cell cilia

A

kinocilium (single)

stereocilia 20-300 (non-motile)

31
Q

kinocilium microtubule arrangement

A

9+2 like other motile cilia

32
Q

stereocilia arrangement

A

increasing length from one side of the cell to another

mechanically linked and move as a bundle

33
Q

ultimately, movement of the ________ produces an electrical signal (hair cells)

A

stereocilia

34
Q

when the stereocilia bends toward the kinocilium, the hair cell ______ and when the stereocilia bends away from the kinocilium the hair cell ________

A

depolarizes, hyperpolarizes

35
Q

lateral line system

A

fishes and amphibians

external receptors based on hair cells

detects movement in water

36
Q

lateral line system receptors

A

kinocilia of many hair cells embedded in an accessory structure called a cupula

cupula bends toward kinocilia when displaced

37
Q

at rest, about __% of channels in a hair cell are open, producing a resting potential of about -____

A

15%, -60mV

38
Q

do hair cells produce APs?

A

no, they release nt in a graded fashion onto primary afferent neurons

39
Q

asymmetry of hair cell output

A

displacement toward kinocilium produces larger depolarization than same displacement away from kinocilium (small hyperpolarization)

40
Q

stratocyst

A

organ that detects an animal’s position and acceleration with respect to gravity

41
Q

stratocyst structure

A

hollow fluid-filled cavity lined with mechanoreceptors that contact the stratolith

42
Q

stratolith

A

structure made of sand grains, calcarous concentrations, or another dense material

must have a higher specific gravity than surrounding fluid

acquired from the animal’s surroundings or secreted by stratocyst epithelial cells

43
Q

what happens to the startolith when an animal moves

A

it rests on different regions of the stratocyst epithelium, which stimulates tonic discharge from ciliated receptor cells

44
Q

2 functions of the vertebrate ear

A

report position of the animal

hearing

45
Q

in vertebrates, the organs of equilibrium reside in a membranous labyrinth with 2 chambers…

A

sacculus and utriculus surrounded by bone and filled with endolymph

46
Q

utriculus

A

gives rise to 3 semicircular canals of the inner ear

hair cells here detect acceleration of the head, endolymph moves the cupula –> bends cilia of hair cells

47
Q

all the hair cells in a semicircular canal have their kinocilia on the ____ side

A

same

so all are excited or inhibited at once

48
Q

maculae

A

3 patches of hair cells below the semicircular canals

Detect tilt

49
Q

what is sound

A

a mechanical vibration that propagates through air or water

travels as waves

50
Q

the external ear functions as a ______

A

funnel that collects sound waves from the air and concentrates the pressure on the eardrum (tympanic membrane)

51
Q

external structures of the ear… pinna and tragus

A

help collection of sound waves and modify directional sensitivity

52
Q

to detect sound, airborne vibrations must be transmitted where

A

from the outer and middle ear to the fluid-filled inner ear where the auditory receptor hair cells are

53
Q

auditory ossicles

A

malleus incus stapes

energy from moving eardrum is transmitted to the ossicles through the oval window to the inner ear

54
Q

cochlea

A

fluid-filled chamber that looks like a snail shell containing the receptor hair cells

hair cells encode frequency and intensity of sound

55
Q

perilymph

A

in the cochlea

high [Na+]

56
Q

organ of corti

A

has cochlear hair cells and bathed in endolymph

57
Q

inner hair cells of organ of corti vs outer hair cells

A

inner hair cells: detect vibrations

outer hair cells: touch tectorial memb and change length rapidly to amplify vibrations

58
Q

cochlear electrical signals reflect _______ of receptor currents from numerous hair cells

A

summation

transduction happens with movement of basilar memb bends tips of stereocilia laterally

59
Q

_______ K+ current depolarizes hair cells of ear

A

inward (unusual b/c of high K+ in endolymph)

60
Q

tip links

A

fine strands that connect each stereocilium to its taller neighbor

when bent, all move and many ion channels are opened TRPA1 channels

61
Q

electrical resonance frequency

A

the frequency a hair cell responds maximally to

62
Q

Basilar membrane stuff

A

Diff freq activate diff regions

Stiff narrow end = high freq and amplitude

Wide floppy end = low freq and amplitude