Unit II - Olfactory Nerve

Question 1

What are olfactory neurons?

Answer 1

Primary sensory neurons

Question 2

What kind of neuron is the olfactory neuron?

Answer 2

Bipolar

Question 3

Where are the olfactory neurons found?

Answer 3

In the epithelium lining the superior part of the nasal cavity.

Question 4

What covers the olfactory epithelium?

Answer 4

A thin layer of mucous

Question 5

Olfactory neurons are supported by what kind of cells?

Answer 5

Supporting cells

Question 6

Olfactory _____ function as receptors.

Answer 6

hairs

Question 7

About how many olfactory neurons convey information to the olfactory bulb?

Answer 7

10-20

Question 8

What make up the 10-20 olfactory nerves?

Answer 8

Central processes (axons) bundled together

Question 9

Are olfactory neuron axons myelinated or unmyelinated?

Answer 9

unmyelinated

Question 10

What are olfactory neurons covered by?

Answer 10

Schwann cells

Question 11

Olfactory nerves pass through what? Which bone is this part of?

Answer 11

cribriform plate

ethmoid

Question 12

When the olfactory neurons pass through the cribriform plate what to they enter into?

Answer 12

The olfactory bulb

Question 13

When the neurons enter the olfactory bulb what do they synapse on?

Answer 13

The detritus of mitral cells

Question 14

What are formed at these synapses between the olfactory neurons and mitral cells in the olfactory bulb?

Answer 14

Synaptic glomeruli

Question 15

Where is the cell body for the olfactory neuron?

Answer 15

In the nasal cavity (superior)

Question 16

What is another name for the olfactory nerve?

Answer 16

fila olfactoria

Question 17

What stimulates the olfactory neuron?

Answer 17

chemoreceptors

Question 18

Mitral cells are what type of neurons?

Answer 18

Secondary sensory neurons

Question 19

Where are mitral cell bodies located?

Answer 19

in the olfactory bulb

Question 20

Mitral cells relay information in what direction?

Answer 20

posterior

Question 21

Mitral cells relay information via the _____?

Answer 21

Olfactory tract

Question 22

At what area do the tract fibers split?

Answer 22

Anterior perforated substance

Question 23

What doe the tract fibers split into?

Answer 23

Medial and lateral striae

Question 24

What do the medial stria fibers do?

Answer 24

They cross the midline

Question 25

Where do the medial stria fibers cross the midline?

Answer 25

At the anterior commissure

Question 26

Where do the medial stria fibers travel to?

Answer 26

The opposite olfactory bulb

Question 27

Do the lateral stria fibers cross over?

Answer 27

no

Question 28

Where do the lateral stria fibers carry information to?

Answer 28

primary olfactory cortex periamygdaloid area prepiriform area, including the uncus

Question 29

The uncus is Broadmann area what?

Answer 29

34

Question 30

Where is the uncus located?

Answer 30

Medial aspect of the temporal lobe.

Question 31

What does it mean clinically that some of the fibers cross over to the other side.

Answer 31

Poor ability to segregate R/L smelling.

Question 32

What is the bridge where the two olfactory tracts come together called?

Answer 32

Anterior commissure

Question 33

How many neurons long is the olfactory pathway?

Answer 33

2

Question 34

The olfactory pathway is a 2 neuron pathway. An exception to the normal 3 neuron pathways. What is different about this pathway?

Answer 34

It bypasses the thalamus - DOES NOT SYNAPSE in the thalamus!

Question 35

What is the total loss of smell called?

Answer 35

anosmia

Question 36

What are two things to know about anosmia?

Answer 36

It's rare and usually congenital

Question 37

What else can cause smell problems?

Answer 37

Skull fractures and CSF leakage

Question 38

What are two other pathways concerning the olfactory nerves?

Answer 38

Terminal nerve and vomeronasal nerve

Question 39

Is the vomeronasal nerve developed well in humans?

Answer 39

NO - poorly developed, used mainly to track prey in animals

Question 40

What is the terminal nerve for and where is it located?

Answer 40

autonomic (visceral) function, on nasal septum

Question 41

What causes CSF leakage here?

Answer 41

A tear in the dura mater