CNS- FA17- Olfactory System

Question 1

Since the olfactory is an older system, is it more or less organized?

Answer 1

Less organized

Question 2

How is the olfactory system different from other sensory systems?

Answer 2

1. Nontopographical
2. Olfactory neurons/olfactory Receptors are modified epithelial
3. Replaced every 1-3 months

Question 3

The mucosa cells are replaced how often?

Answer 3

Every month

This is because when air comes in, they slough off. They can return but, will not always as the same receptor

Question 4

What are the components that compose the olfactory epithelial?

Answer 4

Olfactory neurons- (25 million, unmyelinated, bipolar )

Sustentacular cells

Basal cells

Question 5

Which cell in the olfactory epithelium helps with metabolic functions of the olfactory neurons?

Answer 5

Sustentacular cells

Question 6

Which cells of the olfactory epithelium are the cells that replace the eroded cells?

Answer 6

Basal cells

Question 7

There are 25 million olfactory neurons in the olfactory epithelium, how are the classified?

Answer 7

Bipolar unmeylinated

Question 8

Where do the estimated 25 million olfactory neurons travel?

Answer 8

Through 15 holes in the cribriform plate, becoming the olfactory nerves.

(They don’t travel far)

Question 9

T/F: Mature olfactory have no nucleus

Answer 9

True

Supporting cells do

Question 10

Why do olfactory neurons have cilia?

Answer 10

Cilia increases the surfaces areas for more receptors

Question 11

What is the function of the sustentacular cells?

Answer 11

Process ions and other substances

Question 12

Damage to the upper layer of the olfactory epithelium results in?

Answer 12

Cells will be replaced by basal cells

Question 13

Damage to the lower layer of olfactory epithelium results in?

Answer 13

Reproduction of cells will not occur because basal cells will be destroyed

Question 14

Once the fibers of the olfactory neurons cross the cribriform plate where do they enter?

Answer 14

Olfactory bulb

Question 15

What are the cells in the olfactory bulb?

Answer 15

Mitral cells/Tufted

Glomeruli

Periglomerular cells

Granule cells

Question 16

Cells in the olfactory bulb that are considered the output cells?

Answer 16

Mitral & tufted

Question 17

Which cells in the olfactory bulb axons make up the olfactory tract?

Answer 17

Mitral & Tufted

They leave the bulb

Question 18

Which cells in the olfactory bulb is a knot of fibers that is an area of synapse?

Answer 18

Glomeruli

Question 19

Which cells in the olfactory bulb are interneurons that surround the glomeruli?

Answer 19

Periglomerular cells

Question 20

Which cells in the olfactory bulb are interneurons that are closer to the olfactory tract?

Answer 20

Granule cells

Question 21

Which cells of the olfactory bulb reach into the glomeruli to synapse with the incoming olfactory nerve from fibers that passed through the cribriform plate?

Answer 21

Mitral

Tufted

Periglomerular

Question 22

Olfactory receptor/ Triad:

The olfactory neuron/receptor cell (Excites/inhibits) mitral cells and this path has (one/two) synapse in glomeruli, then goes to the brain.

Answer 22

Excites

One

Question 23

Excitation of (mitral/periglomerular) cells is the fastest path to the brain?

Answer 23

Mitral

Question 24

Olfactory receptor/neurons (excites/inhibit) periglomerular cells.

The periglomerular are (inhibitory/excitatory) and they will shut off_________ cells.

The ______ cells then (excites/inhibits) the Periglomerular cells

Answer 24

Excites

Inhibitory

Mitral

Mitral

Excites

(Mitral cells excitation of the inhitory periglomerular cells allow for stimulus to go unnoticed after a while (i.e. Cologne)

Question 25

The feedback loop of the periglomerular cell to mitral cell then back?

Answer 25

Negative feedback

Question 26

Which pathway of the olfactory triad is the fastest to the brain?

Answer 26

Olfactory neuron —> Mitral cell

Question 27

Mitral cell excitation path to brain?

Answer 27

Olfactory receptor —> + Mitral cell —> olfactory tract —> either to recurrent collateral that turns on granule cell that turns off mitral cell. Or to lateral stria

Question 28

What are the stria that the olfactory tract splits into ?

Answer 28

Medial stria Lateral stria Intermediate stria

Question 29

The olfactory tract splits into this stria, goes to contralateral bulb via anterior commissure, then inhibits contralateral mitral cells indirectly by exciting the granule cells.

Answer 29

Medial Stria *tells direction of odor

Question 30

Olfactory tract splits into this stria that goes to the piriform lobe, an area in the temporal lobe (inferior/anterior including uncus & parahippocampal area)

Answer 30

Lateral stria

Question 31

AKA for piriform lobe?

Answer 31

Olfactory cortex EntoRhinal cortex

Question 32

The piriform lobe is associated with which system?

Answer 32

Limbic *connects smells to memory/emotion

Question 33

The olfactory tract splits into this stria that goes to mediodorsal nucleus of the thalamus, then to the orbitofrontal cortex.

Answer 33

Intermediate stria

Question 34

Which stria ends up in the orbitofrontal cortex that allows for identification of what is being smelled?

Answer 34

Intermediate stria

Question 35

If on the test as an answer choice, which sensory system does not go to the thalamus?

Answer 35

Olfactory *in actuality it does, just answer Mayne’s questions*

Question 36

Which stria helps determine direction of smell?

Answer 36

Medial

Question 37

Which stria connects memory/emotion to smell?

Answer 37

Lateral

Question 38

Which stria is responsible for perception, allowing identification of smell??

Answer 38

Intermediate