Taste and Smell

Question 1

Describe the different papillae on the tongue and what kind of taste receptors there are in each.

Answer 1

Filiform:no taste buds; for touch pain and temperature
Fungiform:anterior part of the tongue(pink dots) & contain
one or more taste buds.
Circumvallate(12): distributed in the shape of an inverted V near the back of the tongue
Foliate: in small trenches on the sides of the posterior
tongue

Question 2

What is meant by the term supertaster?

Answer 2

heightened respons to taste

Women more than men, european 25%, heigthened response maybe due to more fungiformpapillae

Question 3

How do the different taste receptors differ from each other?

Answer 3

different taste cells respond to different categories of

tastes. grouped together

Question 4

How does the intestinal peptide GLP-1 affect taste reception?

Answer 4

Glucagon like peptide is released by tatse cells in response to food. GLP1 alters cells responsivity to taste, MORE sweet, LESS umami. associated with intestinal activity…dessert?

Question 5

Trace the taste pathways from the tongue regions to the insula.

Answer 5

Facial nerve (anterior 2/3)
Glossopharyngeal (posterior 1/3)
Vagus (palate, epiglottis)
–>solitary nucleus in Medulla–>ipsilaterally to the Ventral posterior medial nucelus (thalamus)–>limbic cortex and INSULA

Question 6

Describe how odorants activate receptor cells and how they then stimulate receptor adaptation.

Answer 6

only mucous soluble materials can activate receptors. Odorants activate Na/Ca and Cl ion channels on receptor microvilli–>depolarization and AP.
Adaptation=decreased activity with prolonged stimulation

Ca2+ -dependent and Ca2+-independent pathways that inhibit receptors, close ion channels and enhance outward pumping of ions

Each receptor cell has one odorant
receptor;

Question 7

Describe the piriform cortex (structure, location) and how it processes olfactory information.

Answer 7

Piriform is a primitive cortex in medial surface temporal lobe with only three layers, but has high level characteristics such as consciousness of odors, singularity and habituation

Olfactory bulb projects to piriform cortex–> Piriform cortex projects olfactory information–>amygdala,
hippocampus and prefrontal cortex

Question 8

Describe how the amygdala and orbitofrontal cortex process olfactory information.

Answer 8

amygdala, center for generating emotion associative learning. Amygdala--> hypothalamus to generate olfactory related alterations in autonomic and endocrine systems
Orbitofrontal cortex (PFC). Acts with amygdala in emotion/ associative learning. JUDGES odors,multimodal representations

Question 9

Describe how intranasal substances such as viruses and peptides are transported to the CNS.

Answer 9

Olfactory receptors contact environment and brain
viruses (measles) can be transported along axons to the olfactory bulb and transynaptically to the limbic system.
Bacteria amoebae may penetrate olfactory mucosa
and be transported into the subarachnoid
space–> meningitis.