Olfactory System

Question 1

What is olfaction also called?

Answer 1

Osmatic sense

Question 2

What are the components of the olfactory system?

Answer 2

Olfactory mucosa
Olfactory nerve
Olfactory bulbs
Olfactory tracts
Olfactory Cortex

Question 3

Where is the olfactory mucosa located?

Answer 3

Located in superior aspect of feach nasal fossa (sphenoethmoid recess)

Question 4

What areas of the nasal cavity are included in the olfactory mucosa?

Answer 4

Median nasal septum and lateral wall

Question 5

What epithelia type is found in olfactory mucosa?

Answer 5

Pseudostratified Ciliated Columnar

Question 6

What are olfactory glands also known as?

Answer 6

glands of Bowmen’s

Question 7

What do Glands of Bowmen’s do?

Answer 7

Secretes mucous secretion that covers the olfactory mucosa

Question 8

What are olfactory cells?

Answer 8

bipolar neurons that are modified to serve as the olfactory receptor

Question 9

What is the length of time for olfactory cell turnover?

Answer 9

Active/functional life 2-4 months

Question 10

What are the morphological features of olfactory cells?

Answer 10

Single dendrite that are arborized (branched) branches include odorant receptors in the plasma membrane

Question 11

Are olfactory cells myelinated?

Answer 11

No they are unmyelinated and become the olfactory nerve

Question 12

What forms olfactory nerves?

Answer 12

formed by axons of the olfactory cells

Question 13

What do the axons have to travel through to enter the anterior cranial fossa?

Answer 13

Bundles of axons enter the cranial cavity through the cribiform foramina of the ethmoid bone

Question 14

Where do the axons that enter the olfactory bulb terminate?

Answer 14

In clusters of endings called glomeruli

Question 15

What are olfactory bulbs?

Answer 15

Extension of the brain that is along the ventral surface of the frontal lobe

Question 16

What is the principal neuron of olfaction?

Answer 16

Mitral cells

Question 17

What is the morphology of mitral cells?

Answer 17

Dendrites that arborize within the glomeruli and associate with olfactory cell axons

Question 18

DO mitral cells communicate with more than one olfactory cell?

Answer 18

Yes, one mitral cell communicates with several olfactory cells (convergence helps increase olfactory sensitivity to low odor concentrations)

Question 19

What cell axons comprise most of the fibers of the olfactory tract and where do they project?

Answer 19

Mitral cells comprise most of the fibers of the olfactory tract and project centrally in the brain to the olfactory cortex

Question 20

What are tufted cells?

Answer 20

Another neuron in olfactory bulbs

Question 21

What is the function of tufted cells?

Answer 21

Innervate glomeruli and send some axons through the olfactory tract

Question 22

What cells make up the olfactory tract?

Answer 22

Most fibers are from mitral cells but some are from tufted cells

Question 23

Where does the olfactory tract lead to?

Answer 23

Olfactory trigone at the base of the brain

Question 24

What does the olfactory trigone do?

Answer 24

Appears to split into a lateral olfactory stria and medial olfactory stria

Question 25

Where do most fibers that traverse the lateral olfactory stria go to?

Answer 25

The lateral olfactory area of the cerebrum

Question 26

Where do the fibers that make up the intermediate olfactory stria terminate?

Answer 26

Anterior perforated substance

Question 27

Does the medial olfactory strai include olfactory tract fibers?

Answer 27

No, medial olfactory stria does not include olfactory tract fibers to the septal area as originally thought

Question 28

What does the lateral olfactory area do?

Answer 28

Receives input from the olfactory bulbs through fibers of the lateral olfactory stria

Question 29

What does the lateral olfactory area contain?

Answer 29

Uncus Limen Insula Part of the amygdala

Question 30

What is the uncus?

Answer 30

Anterior part of the parahippocompal gyrus

Question 31

What is the limen insula?

Answer 31

Cortex of the ventral inferior part of the insula

Question 32

What does the uncus, limen insula and part of the amygdala make?

Answer 32

Primary Olfactory area

Question 33

Where is the primary olfactory area found?

Answer 33

Largely in the temporal lobe

Question 34

What is the primary olfactory area responsible for?

Answer 34

Subjective appreciation of an olfactory stimulus (experience of a smell stimulus)

Question 35

What is the olfactory association area?

Answer 35

Cortical areas adjacent to the primary olfacty cortex

Question 36

What does the olfactory association area do?

Answer 36

Permits appreciation of significance of and identify different odors

Question 37

What do the lateral olfactory areas together with hippocampus do?

Answer 37

Serve as important limbic system structures | Therefore this allows odors to influence our emotion, memories and viseral activities

Question 38

Where is the anterior perforated substance found?

Answer 38

positioned between the lateral and medial olfactory stria

Question 39

What does the anterior perforated substance form?

Answer 39

Intermediate olfactory area which plays a role in conscious olfaction

Question 40

What do the anterior perforated substance do?

Answer 40

These neurons mostly connect to important structures and it is involved in emotional and autonomic responses to odor stimuli

Question 41

How do you test the integrity of the olfactory pathway?

Answer 41

Often difficult to distinguish between qualities of smell and taste therefore those who lose smell can't complain that food doesn't taste right

Question 42

What protocols should be followed to test olfactory sensations?

Answer 42

Each nostril should be tested separately Substance should have an odor that's recognizable Substance should be volatile (aromatic) Substance must be non-irrative or else pain stimulus occurs

Question 43

What is anosmia?

Answer 43

Loss of smell

Question 44

What can interrupt the olfactory pathway?

Answer 44

Nasal congestion Fractures of the ethmoid bone meningioma in the floor of the anterior cranial fossa

Question 45

How do fractures of the ethmoid bone interrupt olfactory pathways?

Answer 45

It disrupts the olfactory nerve

Question 46

How do meningiomas on the floor of the anterior cranial fossa interrupt olfactory pathways?

Answer 46

They disrupt the olfactory bulb or tract

Question 47

What are olfactory hallucinations?

Answer 47

Inappropriate sensation of olfaction that are almost always unfamiliar and unpleasant

Question 48

What irritative lesion of the lateral olfactory cortex can cause olfactory hallucination?

Answer 48

Uncinate seizures

Question 49

What occurs with uncinate seizures?

Answer 49

Olfactory hallucinations Convulsive involuntary movements of the lips and tongue Mental confusion right after

Question 50

What lobe is the seizure activity occuring for uncinate seizures?

Answer 50

In the temporal lobe (uncus)