Olfaction (smell)

What are the 5 special senses?

• Olfaction (smell)

• Equilibrium (balance)

• Hearing

• Gustation (taste)

• Vision

Olfactory organs are made up of 2 layers, what are they?

• Olfactory epithelium

  • Has cilia where chemicals can bind

• Lamina propria

What 4 things does the olfactory epithelium consist of?

• Olfactory receptors

• Supporting cells

• Basal cells

• Olfactory glands

Why do olfactory receptors have a short half life and what replaces it?

Why: Because it is prone to damage

Replaced by: Basal cells that differentiate into olfactory receptors

Why are older people less sensitive to smells?

Because basal cells "run out” and the ones that remain are less sensitive

What are olfactory receptors cells?

Highly modified neurons with chemical receptors called odorant binding proteins on the cilla

What are odorants?

Chemicals that bind to the ordorant binding proteins in olfactory receptors

Function of olfactory glands?

Secrete mucus

What is the olfactory pathway?

1. Olfactory epithelium

   1. Axons leave the olfactory epithelium

   2. Pass through the cribriform foramina

2. Olfactory nerve fibers

   1. Synapse on neurons in the olfactory bulbs

   2. Impulses travel to the brain via CN I

3. Olfactory bulb

4. Olfactory tract

5. Central nervous system

   1. Arrive at the cerebral cortex, hypothalamus, and limbic system

How can we detect different smells?

Because epithelial receptors have different sensitivities

Olfactory Dysfunction

Associated with

Defintion

Types

• Ansomia =

• Hyposmia =

• Dysosmia =

Associated with: Corona viruses and SARS-CoV-2

Defintion: Loss of sense of smell or taste

Types:

• Ansomia = Inability to detect one or more smells

• Hyposmia = Reduced ability to detect odor

• Dysosmia = Altered perception of smell