Olfacti

Olfaction is what?

The sense of smell

Organs for olfaction is located?

In nasal cavity

What are the two layers of olfactory organs?

• olfactory epithelium

• Laminate propria

Olfactory nerve

I

What are the steps in olfaction?

1. Inhale

2. Pass through epithelium

3. Reach olfactory nerve in the epithelium

4. Odorant binds to its receptor→ activates adenylate cyclase

5. Adenylase cyclase converts ATP to cAMP

6. CAMP opens Na channels which leads to depolarization

7. Synapse at olfactory bulb

8. Pass through olfactory tract

9. Go to olfactory cortex

Olfactory epithelium layer contains

• Olfactory Sensory neurons

• Supporting cells

• Basal cells (stem cells)

Olfacotry sensory cells are

• bipolar neurons

• Detects chemicals as they interact with odorant-binding proteins

What is gestation?

Taste

Gustatory epithelial cells are

Taste receptors that are found in taste buds

Types of lingual papillae

• validate papilla

• Foliage papillae

• Fungiform papilla

• Filiform papillae

Filiform papillae

Provide friction to move food around mouth

•Do not contain taste buds

Fungiform papillae

Contain 5 taste buds each

Vallate (Circumvallate) papillae

•Contain as many as 100 taste buds each

Petal like structure on tongue

Foliate papillae

Have taste buds

Microvili (taste hairs) extends through what?

The taste pore

Pathway of gustation

• tongue

• Solitary nucleus of medulla oblongata

• Thalamus

• Gustatory. Cortex of insult

Umami

Savory taste imparted by glutamate

How does gustatory discrimination happen?

Two pathways: one for salt and sour, another for sweet, bitter, umami

1. Na of H+ enters through sodium gated channels which leads to depolarization

2. Sensations bind to G proteins called gustducins

3. use second messengers to depolarize

CN involved in gustation

VII- anterior 2/3 tongue

IX- posterior 1/3 tongue

X- surface of epiglottis