Chemosensation - Restrepo

Question 1

loss of sense of taste

Answer 1

Ageusia

Question 2

Altered perception of taste

Answer 2

Dysgeusia

Question 3

Loss of sense of smell

Answer 3

Anosmia

Question 4

Diminished sense of smell

Answer 4

Hyposmia

Question 5

Altered or distorted sense of smell

Answer 5

Dysosmia

Question 6

Altered perception of smell in the prescence of an odor, usually unpleasant

Answer 6

Parosmia

Question 7

Phantosmia

Answer 7

Ghost perception of smell

Question 8

Stimulation of what three senses defines what we generally define as “taste”?

What cranial nerves are responsible for each?

Onto what nucleus does each synapse?

Answer 8

Olfaction - CN 1, Olfactory bulb
Gustation - CN 7, 9, (10), Solitary nucleus
Chemesthesis - CN 5, SPINAL TRIGEMINAL NUCLEUS

Question 9

Chemotherapy damages rapidly dividing cells. What two groups of cells involved in “taste” will be affected?

Answer 9

Olfactory receptor neurons

Taste buds

Question 10

What is the receptor type for CN 5 receptors that sense chemesthesis?

Answer 10

Free nerve endings in the mucosa.

Question 11

What is the receptor type for CN 7, 9, 10?

Answer 11

Modified epithelial cell

Question 12

What is the receptor type for CN1?

Answer 12

Ciliated, bipolar neuron

Question 13

Papillae located on the front of the tongue are called _____ and are innervated by the _____.

Answer 13

Fungiform, Facial nerve (chorda tympani)

Question 14

Papillae located on the posterior 1/3 of the tongue are called _____ and are innervated by _____.

Answer 14

Circumvallate, Glossopharyngeal

Question 15

Taste buds located in the soft palate are innervated by the ______.

Answer 15

superior petrosal branch of the facial nerve

Question 16

Taste buds in the _____, _____, and _____ are supplied by the vagus. Taste buds in these posterior areas are thought to be important in gag reflexes designed to stop intake of spoiled foods or noxious compounds.

Answer 16

extreme posterior tongue, oropharynx and epiglottis

Question 17

You drink hot coffee and burn the f*%& out of the front part of your tongue. What nerve has notified your brain of this unfortunate situation?

Answer 17

CN5.

Question 18

Sour, sweet, salty, umami, bitter. Which of these are ion-channel based vs. G-protein coupled?

Answer 18

Ion channel: Sour, salty

Gprotin: Sweet, umami, bitter

Question 19

Taste Transduction for sweet, umami, bitterinvolves a complex G-protein coupled, biochemical amplification system. What neurotransmitter is used?

Answer 19

ATP.

Question 20

After CN 7, 9, 10 synapse on the nucleus of the solitary tract, they send axons to two primary destinations. What are they, and what purpose does each serve?

Answer 20

Insular cortex (conscious appreciation of taste)

Amygdala/Hypothalamus (appetite control, sub conscious reactions to taste)

Question 21

What area of the brain receives input from both olfactory and gustatory neurons, and is the likely location where the perception of “taste” is formed?

Answer 21

the orbitofrontal cortex.

Question 22

The olfactory neuron must depolarize to send a signal to the olfactory bulb? What feature is unique about this pathway?

Answer 22

G-protein coupled.

Golf–> AC –> cAMP –> Na/Ca channel opens–> high Ca levels –> Cl- channel–> Cl LEAVES, furthering
depolarization.

So the unique feature is a high intracellular concentration of Cl- with regard to the ECF.

Question 23

Axons of the olfactory nerve must penetrate the cribriform plate, which is part of the ___ bone, to reach the olfactory bulb.

Answer 23

ethmoid

Question 24

Each taste bud contains 50-100 taste cells, each with the (same or different) receptor specificity. Afferents from these taste cells travel to the olfactory bulb where they synapse onto a glomerulus which is (specific or nonspecific) for a given receptor specificity.

Answer 24

Different, specific

This creates a flavor “map” on the bulb, which allows the brain to differentiate.

**receptors can bind more than one type of molecule, so a given molecule may activate many glomeruli. The system is similar to the visual pathway where the brain must recognize a pattern to distinguish individual flavors.

Question 25

True or false. The olfactory system is the only sense that transmits directly to the cortex, bypassing the thalamus.

True of false. Also projects to the amygdala.

Answer 25

True dat.

True. That’s why people hook up with their ex…probably.

Question 26

Smell association with memory takes what path from the olfactory bulb to its final destination?

Answer 26

Olfactory bulb–>tract–>entorhinal cortex–>hippocampus

Question 27

Smell association with conscious perception takes what path from the olfactory bulb to its final destination?

Answer 27

Olfactory bulb–>tract–>Piriform cortex–>MD thalamus –>orbitofrontal cortex (remember this is where it meets up with gustatory neurons)

Question 28

Smell association with Visceral reactions and homeostasis take what path from the olfactory bulb to its final destination?

Answer 28

Bulb–>tract–>olfactory tubercle OR amygdala–> hypothalamus