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):
1

chemoreceptors are specialized for info about the... and 2 types

chemical envir and transmitting it to neurons

gustatory (taste) receptors

olfactory receptors

2

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

aqueous solution

3

sensilla/sensillum

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

4

taste in a housefly

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

each is sensitive to a different chemical stimulus

5

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

yes, it will lower its proboscis to feed

6

where are taste receptors found in terrestrial vertebrates?

tongue

epiglottis

back of the mouth

pharynx/upper esophagus

7

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

taste buds, basal cells

8

basal cells

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

9

5 taste qualities

sweet

salt

sout

bitter

umami (MSG)

10

evolution of taste qualities

sweet - rich in calories

salt - maintain water balance

sour/bitter - toxic/danger

11

salty mechanism

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

sour mechanism

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

Block K+ channels

depolarizes cell

13

sweet mechanism

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

14

bitter mechanism

quinine blocks K channels in apical memb

small resting Na current depolarizes the cell

15

bitter mechanism under study

quinine binding activates G protein gustducin

actives phospholipase C which increases IP3 to release Ca

16

do vertebrate taste receptors make APs?

yes, but don't have axons

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

17

labeled line coding

receptors connected to a specific set of axons

18

olfactory receptors in vertebrates

found in the nasal cavity (line turbinates)

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

19

vomeronasal organ

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

for pheremones

20

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

dendrite, knob, surface

thin cilia covered in the protein soln mucus

21

only _______ olfactory neruons respond to odors

ciliated

22

nasal olfactory transduction cascade

G protein activates adenylyl cyclase that increases intracellular cAMP

cAMP opens cation-selective channels --> depolarization

23

APs from olfactory receptor axons carry the signal where

olfactory bulb of the brain

24

glomeruli

spherical clusters of neurons

ex. olfactory bulbs of insects and invertebrates/vertebrates

25

what kind of stimulus activates mechanoreceptors

a stretch or distortion of plasma membrane

uses ion channels

26

sensory bristle

found of the surface of insects

a stiff hair associated with a single bipolar sensory neuron

27

endolymph

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

28

what happens when an insect sensory bristle is moved

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

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

29

hair cells of vertebrates

extremely sensitive mechanoreceptors

many cilia from the apical end of each cell

coupled by kinocilium to accessory structures

30

2 classes of hair cell cilia

kinocilium (single)

stereocilia 20-300 (non-motile)

31

kinocilium microtubule arrangement

9+2 like other motile cilia

32

stereocilia arrangement

increasing length from one side of the cell to another

mechanically linked and move as a bundle

33

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

stereocilia

34

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

depolarizes, hyperpolarizes

35

lateral line system

fishes and amphibians

external receptors based on hair cells

detects movement in water

36

lateral line system receptors

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

cupula bends toward kinocilia when displaced

37

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

15%, -60mV

38

do hair cells produce APs?

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

39

asymmetry of hair cell output

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

40

stratocyst

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

41

stratocyst structure

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

42

stratolith

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

what happens to the startolith when an animal moves

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

44

2 functions of the vertebrate ear

report position of the animal

hearing

45

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

sacculus and utriculus surrounded by bone and filled with endolymph

46

utriculus

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

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

same

so all are excited or inhibited at once

48

maculae

3 patches of hair cells below the semicircular canals

Detect tilt

49

what is sound

a mechanical vibration that propagates through air or water

travels as waves

50

the external ear functions as a ______

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

51

external structures of the ear... pinna and tragus

help collection of sound waves and modify directional sensitivity

52

to detect sound, airborne vibrations must be transmitted where

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

53

auditory ossicles

malleus incus stapes

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

54

cochlea

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

hair cells encode frequency and intensity of sound

55

perilymph

in the cochlea

high [Na+]

56

organ of corti

has cochlear hair cells and bathed in endolymph

57

inner hair cells of organ of corti vs outer hair cells

inner hair cells: detect vibrations

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

58

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

summation

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

59

_______ K+ current depolarizes hair cells of ear

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

60

tip links

fine strands that connect each stereocilium to its taller neighbor

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

61

electrical resonance frequency

the frequency a hair cell responds maximally to

62

Basilar membrane stuff

Diff freq activate diff regions

Stiff narrow end = high freq and amplitude

Wide floppy end = low freq and amplitude