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Flashcards in Olfaction and Gustation Deck (42)
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1

3 types of cells in the olfactory epithelium.

Supporting cells - mature to become basal cells
Basal cells - mature to become olfactory receptor cells
Olfactory receptor cells - neuronal in nature but have capability of regeneration, have a typical life span and at end of it will die, replaced by basal cells, constant turnover of olfactory receptor cells

2

1st order cells of Olfactory system.

olfactory receptor cells

3

1st order axons are projected through cribriform plate to this.

olfactory bulb

4

From the bulb the _____ and ____ are developed, creating the 3 pathways that 2nd and 3rd order fibers will take to get to the olfactory cortex.

tract & stria

5

Jacobson’s Organ/Vomeronasal Organ.

- area of olfactory epithelium that is very vestigial in nature, embedded in vomer bone of nose
- pheromone detection/recognition
- synchronize female menstrual cycles
- affect female choice of mates
- cause mother/infant bonding
- alter concentration, productivity
- change perception of people/environments
- classical conditioning

6

The olfactory cortex processing of information bypasses the?

thalamus

7

Olfactory epithelium anatomy.

- receptor cells located in patch of tissue 3 cm square in size
- embedded in epithelium and apex of cells will have series of cilia that are exposed to external world
- axons will bundle to create fascicles to pass through cribriform plate to the olfactory bulb to synapse on 2nd and 3rd order cells IN bulb

8

How do the cilia function?

- cilia are normally in mucous, which traps the odorant and allows it to diffuse through to bind with receptors on the cilia themselves
- receptors for odorants cause chemical changes, initiating action potential that if made to axon will propagate to the bulb

9

Explain the neuron synapses that occur during smell.

receptor cells-->cribiform plate-->glomeruli-->mitral and tufted cells-->granular and periglomerular spread laterally-->anterior olfactory nucleus-->final output-->stria-->amygdaloid nucelus (olfactory cortex)

10

Medial stria

from one olfactory bulb and tract to the contralateral olfactory bulb and tract

11

Primary odors.

Musky - perfumes/aftershave
Putrid- rotten eggs (sulfur)
Pungent- vinegar
Camphoraceous- mothballs, vicks vapor rub
Ethereal- dry cleaning fluid, ozone, cleaning solutions
Floral- roses
Pepperminty- mint gum

12

Mechanism of excitation for smell.

G-coupled protein/metallic Ion binding sites- 350 human receptor genes, ~ 1300 mouse genes, ~10,000 odors detected, odors highly subjective based on gender, age, state of health, personal history

13

Olfactory receptor cell.

Pear shaped cell, On outside of epithelial lining is a bulbous knob with series of cilia, they are neurons and mitotic

14

How are smells differentiated?

labeled lines coding, all take the same path but every type of smell/odor is going to have a specific code, also graded receptor potentials (concentration)
Ex: peppermint may be burst of 4 action potentials, whereas putrid will be a burst of 10 action potential in a row

15

T/F First order taste cells are neurons.

False

16

Anatomical papillae of taste buds.

Fungiform papillae - taste buds located along the border
Foliate papillae - taste buds along the side
Circumvallate Papillae - taste buds are inside groove surrounding the papillae

17

T/F Taste receptors are regenerate.

True

18

T/F Second order cells for taste are neurons.

True

19

Morphology of taste receptors.

- same for taste buds, regardless of the type of papillae they are located in
supporting cells-->basal cells-->receptor cells
- Receptor cells will have afferent innervation, that will be the first neuron in the system, but the second order cell in the system

20

Sweet taste.

- caused by organic molecules that cause a stereochemical interaction with receptor cell, initiating AP and stereochemical interactions
organic molecules with more hydroxyl groups will be sweeter than those organic molecules with less hydroxyl groups

21

Salty taste.

- made of ionized salts
- dependent on conc. of cations in salt

22

Sour taste.

due to proton concentration (Hydrogen ions)

23

Bitter taste.

- long chain organic molecules + nitrogen
- By attaching a nitrogen atom it creates a more basic compound (Alkaloids)
- Major poisons are alkaloids, are easily detectable in very low conc.

24

Umami taste.

- L-glutamate
- Certain ribonucleotides i.e. guanosine monophosphate (GMP) and inosine monophosphate (IMP)
- “pleasant savory taste”

25

Metallic taste.

Dysgeusia- zinc deficiency, certain drugs
Pathological condition - detecting metallic on a regular basis

26

Thresholds for taste.

Sweet: 0.01 moles of glucose
Salt: 0.01 moles of NaCl
Sour: 0.001 moles of HCl
Bitter: 0.00001 moles of quinine
(threshold is less for substances that could harm the body i.e. poisons)

27

T/F All receptors anywhere on the tongue can detect all flavors.

True

28

Taste coding.

- Along Labeled Lines
- Patterns of Neural Activity

29

Taste Receptors are carried by CN?

VII, IX, and X (each nerves will ascend ipsilaterally to solitary nucleus in medulla)

30

Ipsilateral pathway for taste.

Afferent Fibers-->Solitary Nucleus-->VPM of the thalamus (head region)/Parabrachial nucleus/hypothalamus-->Postcentral gyrus- insular cortex/amygdala