Olfactory System Flashcards Preview

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Flashcards in Olfactory System Deck (37):
1

Describe the path of the Olfactory nervous network from the mucosa cells in the nose and mouth to the cortex.

- Olfactory receptor cells (chemoreceptors) in mucosa
- Project to form olfactory fila
- Pass through ethmoid bone
- Collect into olfactory bulb on the inside on the inferior surface of the frontal lobe
- Projections from bulb form olifactory tract

2

What type of cells are the olfactory receptor cells?

Chemoreceptors

3

What are the 2nd order cells found in the olfactory bulb called?

Mitral cells

4

What is the principal central projection pathway for the olfactory system?

- Lateral olfactory tract

5

What do the fibers of the lateral olfactory tract project to?

- Primary olfactory cortex (amygdala nad parahippocampal gyrus)
- Amygdala

6

Where do the fibers not included in the lateral olfactory tract project to?

The anterior olfactory nucleus

7

What is the path from the olfactory tract to the anterior olfactory nucleus?

Fibers project back through the olfactory tracts to both bulbs, with some fibers crossing in the anterior commisure

8

Where does the olfactory information from the primary olfactory cortex and amygdala project to?

- Hypothalamus
- Limbic structures
- Thalamus

9

How is the hypothalamus related to smell?

Connects smell to the autonomic nervous system

10

What limbic structures receive smell information?

- Hippocampus
- Rest of amygdala

11

What portion of the neocortex is related to olfaction?

Orbital cortex

12

What 2 functions related to smell does the Orbital cortex perform?

- Discriminates and identifies food odors
- Perceives taste and flavor

13

What nucleus of the thalamus does the orbital cortex project to?

Dorsomedial nucleus

14

Why does smell have an effect on memory?

Orbital cortex projects to hippocampus

15

What portion of the temporal lobe in the olifactory lobe?

Rostral portion

16

What is the loss of the ability to smell?

Anosmia

17

What is distortion of the usual sense of smell?

Parosmia

18

What is the loss of taste sensation?

Ageusia

19

What types of deficits typically resut from head injuries or neurodegenerative disease?

Sensorineural olfactory deficits

20

Why is smell a useful diagnostic tool for tumors growing on the base of the skull?

Tumors growing on the orbital surface of the frontal lobe can become large before affecting any other sensation besides smell

21

What type of deficits prevent the process of odorants reaching the olfactory epithelium?

Conductive olfactory deficit

22

What can cause conductive olfactory deficits?

- Nasal polyps
- Septal deviations
- Inflammation

23

What area of the cortex may be involved in seizures following an unpleasant illusion of smell or taste?

The uncus

24

What motor phenomena may result from uncinate seizures?

- Smacking of the lips
- Chewing movements

25

What cognitive changes can occur in uncinate seizures?

- Dreamy states
- Deja vu

26

What cranial nerves carry taste sensation?

CN VII: Anterior 2/3rds
CN IX: Posterior 1/3rd

27

What portion of the thalamus receives taste projections?

Ventroposterior medial nucleus

28

What is the primary taste cortex?

Insula

29

What is the secondary taste cortex?

Oribtofrontal cortex

30

What does the ventroposterior medial nucleus project to first? Second?

- S1 to localize taste on tongue
- Insula
Secondary: Orbitofrontal cortex

31

What 2 structures provide a feeding role to the taste pathways?

Lateral hypothalamus
Amygdala

32

What other centers can project to the frontal lobe in a similar fashion to smell?

Vision

33

What nucleus in the brain stem receives taste projections?

The solitary nucleus

34

How is the OFC related to behavior?

Taste is tied to the reward system

35

What is unique about the how the olfactory system and the cortex?

Connects directly to the cortex

36

What types of chemicals is smell intended to detect?

Violatile chemicals

37

What tissue are the olfactory receptor cells found in?

Olfactory epithelium