11b chemoreception

Question 1

chemoreception

Answer 1

is the sensory response to a chemical stimulus.

most ancient of all sensory systems.

The medulla which sends signals to the muscles involved in breathing, and the pons which controls the rate of breathing.

Question 2

interoreceptors

Answer 2

receive stimuli from inside the body

Question 3

exteroreceptors

Answer 3

receive stimuli from outside the body

Question 4

minute ventilation

Answer 4

volume (L) of air breathed in one minute.

controlled by the respiratory center in the brainstem

Question 5

define respiratory center

Answer 5

is made up of three major respiratory groups of neurons, two in the medulla and one in the pons.

In the medulla they are the dorsal respiratory group, and the ventral respiratory group.

Question 6

ventral respiratory group

Answer 6

controls voluntary forced exhalation and acts to increase the force of inspiration.

pons

Question 7

dorsal respiratory group

Answer 7

(nucleus tractus solitarius) controls mostly inspiratory movements and their timing.

medulla oblongata

Question 8

aortic and carotid body receptors

Answer 8

small clusters of chemoreceptors that are part of the major peripheral sensory input

convert the hypoxic signals into an increased neural activity to produce reflex responses in the respiratory and cardiovascular systems.

Question 9

The respiratory center receives

Answer 9

sensory and peripheral input

Question 10

If fluid pH changes, the respiratory center triggers a reflex that either

Answer 10

increases respiration rate or
decreases respiration rate
… to keep CO2 partial pressure within normal limits.

Question 11

2 types of Chemoreceptive exteroreceptor systems can be

Answer 11

olfactory system (smell ) 
gustatory system (taste )

Question 12

olfaction

Answer 12

occurs in specialized structures
(e.g., antennae; nose)
usually (not always) located in or on the head
airborne stimuli (molecules) must be dissolved in aqueous solution before they can bind to receptors

Question 13

gustation

Answer 13

is mediated by specialized organs
usually (not always) located in or near the mouth.
stimuli (molecules) must be dissolved in aqueous solution before they can bind to receptors.

Question 14

water vs terrestrial gustation and olfaction

Answer 14

In water, stimulus molecules are already dissolved and present in the medium.
This means that taste and smell should be less distinct from each other.

Still, aquatic animals have receptors separated in different body regions.
Labeled lines permit discrimination between chemical stimuli.

Chemical stimuli in terrestrial environments are more distinct than in water.

Question 15

aquatic fishes gustation and olfaction include

Answer 15

taste receptors both in mouth and on skin

separate olfactory and gustatory systems.

Question 16

terrestrial gustation and olfaction

Answer 16

Animals must
physically collect stimulus molecules
dissolve them in aqueous fluid
…before the molecules can elicit a receptor potential.

Question 17

Insect gustatory receptor neurons (GRNs) are located within

Answer 17

bristles or sensilla similar to a mechanosensory sensilla.

bristles? a short stiff hair, typically one of those on an animal’s skin, a man’s face, or a plant.

Question 18

taste sensillum contains

Answer 18

dendrites of up to four chemoreceptor cells

in some cases, dendrites of one mechanoreceptor

Question 19

The deterrent cell responds to

Answer 19

[very high salt] and noxious alkaloids.

responds to quinine (a bitter crystalline compound present in cinchona bark, used as a tonic and formerly as an antimalarial drug

tonic = gradually strengtens

Question 20

Higher stimulus concentration elicits

Answer 20

higher RP frequency.

Question 21

Each chemoreceptor cell is sensitive to the same or different class of stimulus?

Answer 21

One cell responds to a range of sugar concentrations.
One cell responds to a range of salt concentrations.
One cell responds to plain water (with just enough salt to allow conduction).

Question 22

Taste sensilla for insects may be located on

Answer 22

the tarsus (terminal segment of the leg; the “foot”)
the proboscis or other mouthpart
antennae

Question 23

When an insect steps on positive stimulus molecules (e.g., sugars)

Answer 23

receptors trigger mouthpart/proboscis extension reflex

insect automatically samples the potential food source

Question 24

when an insect steps on negative stimulus molecules (e.g., toxic alkaloid)

Answer 24

• receptors trigger mouthpart/proboscis retraction reflex
• insect automatically avoids dangerous substance
• although one bug’s trash is another bug’s treasure

Question 25

Flies detect tastants (taste molecules) via gustatory receptor neurons (GRNs) in sensilla on the

Answer 25

labellum (each of a pair of lobes at the tip of the proboscis mouth parts in some insects.)

tarsae ((terminal segment of the leg; the “foot”))

wing margins.

Question 26

Food inside the mouth is tested by GRNs that are located where?

Answer 26

the taste pegs on the inner labellum and pharynx.

Question 27

labeled line system

Answer 27

helps to determine which are Attractive responses and aversive responses

from link: The LL model claims in its extreme form that a stimulus identity is encoded by a distinct set of neurons, serves one function, and is conveyed unprocessed from periphery to behavior.

supported by molecular biological studies of the peripheral taste system of mammals and insects by the expression of functionally different receptor proteins in separate populations of taste receptor cells

Question 28

what type of sensory cells do Vertebrate gustatory receptors have>? also define the word

Answer 28

epithelial sensory cells

Question 29

each olfactory neuron has how many receptors?

Answer 29

it has a receptor for only one type of smell

Question 30

glomerulus

Answer 30

bunch of nerve fibers that tranfers info from nose goes to the brain to integrate the stimuli

Question 31

mitral cells

Answer 31

relay info to the brain and identifies the volatile smell coming from the brain

Question 32

taste buds

Answer 32

Mammalian taste cells are grouped together

Question 33

papillae

Answer 33

small swellings on the tongue.

they swell due to Hot foods or drinks can burn your taste buds, causing them to swell up. … Eating spicy foods like hot peppers or foods that are very acidic like citrus fruits can irritate your tongue. stress. Being under stress has been linked to many health issues, including swollen, enlarged papillae.

Question 34

filiform papillae

Answer 34

located on anterior 2/3 of tongue
most numerous type of papilla
no associated taste receptors
contain mechanoreceptors, and sense touch
are responsible for the tongue’s rough texture
connective tissue core is covered by keratin-rich epithelium
very rough tongues (e.g., cat) have even higher concentrations of keratin

Question 35

what makes the filiform papillae different from the rest?

Answer 35

it does not have any taste receptors

Question 36

fungiform papillae

Answer 36

associated with taste receptors
located mostly at the tip of the tongue
also scattered among the filliform papillae
relatively few taste buds

Question 37

taste buds vs taste receptors

Answer 37

Taste buds contain the taste receptor cells, which are also known as gustatory cells

Each bud has 50-150 receptor cells that differ in morphology and function.

diff taste receptors are:
salty, sweet, bitter, sour, and umami

Question 38

foliate papillae

Answer 38

associated with taste receptors
located on lateral borders and back of tongue
no keratin, so soft in texture
numerous taste buds
these are the ones that become inflamed and swell, causing annoyance!

Question 39

circumvallate papillae

Answer 39

associated with taste receptors
located at the back of the tongue
each has thousands of taste buds
in humans, 8-12 located on the back of the tongue

Question 40

taste bud I II and III differs from IV b/c

Answer 40

the first three each mediate different taste qualities.

Type IV (basal cells) give rise to new taste receptor cells that is located at the basal portions near the nerve fibers

Question 41

pheromones is what type of communication? like is it intra or interspecific attraction?

Answer 41

it is intraspecific because only a male within the same species can recognize the realease of the female within the species

very sensitive nose is needed to dectect the pheromoes from miles away

also function in:
sex-attraction 
trail-marking 
alarm pheromones 
colony-recognition

Question 42

Ionotropic transduction

Answer 42

deals with salty and sour taste receptors

Question 43

type 1 receptor is salty b/c

Answer 43

the simplest

Salt taste receptor cells depolarize with increasing Na+-influx.

Question 44

type 3 receptor is sour b/c

Answer 44

is triggered by protons.
protons are primarily responsible for sour taste
protons interact with distinct channels on Type III apical membranes.
This activates proton-gated cation and Cl- channels to trigger RP.

Question 45

Metabotropic (GPCR) transduction deals with what type of receptors?

Answer 45

bitter sweet and umani

These all occur in different sub-populations of Type II receptor cells.
Cells that sense each taste use different GPCRs that can form dimers.
Taste receptor type 1 membeR 1 (T1R1)
Taste receptor type 1 membeR 2 (T1R2)
Taste receptor type 1 membeR 3 (T1R3)

Sweet activates the T1R2/T1R3 dimer
Umami activates the T1R1/T1R3 dimer
Bitter activates any of a large family of T2R receptor proteins

Question 46

diff btwn gustation and olfactory sensillum s

Answer 46

Gustatory sensillum: one terminal pore

Olfactory sensillum: entire shaft perforated with pores.

Question 47

odorants?

Answer 47

a substance giving off a smell, especially one used to give a particular scent or odor to a product.

Question 48

describe the bipolar neurons that olfactory receptor cells have

Answer 48

Cell bodies are housed in a layer of epithelium
One dendrite reaches the surface to meet the ambient medium
The other dendrite forms a long axon connecting directly to brain

Question 49

what does the watery mucus do for cells that are coming through our nose

Answer 49

protects the vulnerable nerve cells from toxins
regulates access of chemical odorants to the sensory cell’s membrane receptor sites
enzymatically breaks down spent pheromone molecules

Question 50

how long do vertebrate olfactory cells last?

Answer 50

30-90 days

Question 51

anosmia:

Answer 51

Damage to the receptor cells and/or their stem cells
can result in anosmia: the lack of sense of smell.
Anosmia can be transient or permanent.

Question 52

Glomeruli

Answer 52

All axons of the same receptor type converge at one or two locations in the glomeruli.
Glomeruli are spherical regions in the brain’s olfactory cortex
where sensory receptors synapse onto processing neurons.

Question 53

Variations in GPCR amino acid sequence

Answer 53

determine which stimulus ligand can bind there.

Each receptor cell has one to a few different types of receptor proteins.

Question 54

olfactory smell process

Answer 54

1. Airborne molecules bind to mucous proteins on the sensory cell membrane.
2. The stimulus molecule acts as a ligand,
   binding to an olfactory receptor protein (usually GPCR).
   Variations in GPCR amino acid sequence
   determine which stimulus ligand can bind there.
3. cascade begins

Question 55

vomeronasal organ

Answer 55

This includes most mammals, but not humans.
The vomeronasal organ is an odor-specialist.
It detects pheromones and other chemical signals
urinary proteins
lipid secretions
…which are important components of scent markings

Question 56

do Animals have different ways of delivering molecules to the VNO?

Answer 56

yes!

reptiles, via tongue flicking
in mammals, through the nasopalatine duct

Question 57

vomeronasal organ (VNO) are helpful because?

Answer 57

They predominantly help mediate responses to pheromones,
which play important roles in a variety of behaviors
defense
recognition of young
mating
aggression

Question 58

flehmen response

Answer 58

pulls stimulus-laden air into the nasopalatine duct, facilitating detection of pheromones (and other chemical stimuli).

Question 59

Taste Mutants and Natural Selection for cockroaches

Answer 59

American scientists found that the mutant cockroaches had a “reorganised” sense of taste, making them perceive the glucose used to coat poisoned bait not as sweet but rather as bitter.