Olfaction

Question 1

The olfactory bulb containes 4 types of cells

Answer 1

Output cells - Mitral Tufted Cells

Inhibitory interneurons - Periglomerular cells Granule Cells

Question 2

Where do the Olfactory Neurons synapse on thedendrites of mitral and tufted cells (olfactory bulb)?

Answer 2

glomeruli

Question 3

The fibers of the lateral olfactory tract terminates in 5 areas

What are they?

Answer 3

1) The anterior olfactory nucleus (AON)
2) anterior and posterior cortical nuclei of the amygdala,
3) the olfactory tubercle,
4) a portion of the entorhinal cortex
5) piriform cortex.

Question 4

What sends axions to the ipsalateral olfactory bulb?

Answer 4

The anterior olfactory nucleus (AON)

Question 5

What is considered the primary olfactory cortex and receaves the most olfactory inputs

Answer 5

Piriform cortex

Question 6

Hyposmia

Answer 6

reduced ability to detect odors.

Question 7

Anosmia

Answer 7

complete inability to detect odors

Question 8

Parosmia

Answer 8

change in the normal perception of odors

Question 9

Phantosmia

Answer 9

the sensation of an odor that isn’t there

Question 10

What can cause hyposmia or absence of smell (anosmia)

Answer 10

A blow to the head

can shear or sever receptor axons passing through the cribiform plate. If axons are severed, there is often permanent anosmia, but if axons are slightly sheared there can be recovery due to receptor cell regeneration.

Question 11

Olfactory hallucinations (phantosmia) can result from

Answer 11

lesions of the parahippocampal gyrus

Question 12

produce hallucinations of repugnant odors

Answer 12

Focal seizures in the parahippocampal gyrus (uncinate seizures)

Question 13

Diseases associated with olfactory deficits

Answer 13

Alzheimer’s

Parkinson’s

MS

Schizophrenia

Question 14

Three types of taste bud papillae on the tongue

Answer 14

Fungiform

Circumvallate

Foliate

Question 15

5 basic types of tastes

Answer 15

Sweet

sour

salty

umami

bitter

Question 16

Three nerves that inneravate the taste sensation of the tongue

Answer 16

VII - chorda tympani (Facial Nerve) - anterior 2/3 of tongue

IX - Glossopharangeal - posterior 1/3 of tongue

X- Vagas nerve - pharnex

Question 17

Where do all the taste nerve synapse?

Answer 17

Nucleus of the solitary tract

Question 18

Where does the solitary tract synapse

Answer 18

Ipsalaterally on the ventroposterior medial of the Thalamus

Then on to the insular and frontal taste cortices

Question 19

Hypogeusia –

Answer 19

reduced ability to taste

Question 20

Ageusia –

Answer 20

complete loss of taste.

Question 21

Dysgeusia –

Answer 21

a foul or metallic taste in the mouth

Question 22

Glossopharyngeal Neuralgia

Answer 22

Damage to nerve IX occasionally produces attacks of severe pain in the throat that radiates to the neck and jaw.

Question 23

Loss of Gag Reflex:

Answer 23

A somatosensory component relays touch, pain, temperature from the posterior tongue and pharynx, skin of the external ear and tympamic membrane. Absence of a gag reflex is an indicator of damage to nerve IX

Question 24

Causes of taste disorders:

Answer 24

Genetics

Upper respiratory and middle ear infections (damage to nerve VII).

Chemotherapy/radiation therapy for cancers of the head and neck (destroys olfactory and gustatory receptor cells)

Surgeries – (i.e. middle ear surgery)

Chemical exposure or medications

Poor oral hygiene and dental problems