OLFACTORY
- The olfactory organ, responsible for our sense of smell, is located in the upper part of the nasal cavity.
- The lofactory n. is the first cranial nerve (CNI) ← bundle of axons
- * It is unique among the cranial nerves, bec. it orginates directly from the olfactory epithelium in the nasal cavity, not from the brainstem.
Structure:
- 1. Olfactory Epithelium: located in the upper part of the nasal cavity
- Specialized tissue that contains the primary cells involved in detecting odors:
1.1 Olfactory Receptor Neurons (ORNs):
- ↳ Bipolar receptors with hair-like extensions called olfactory cillia. (immotite)
- ↳ Responsible for detecting & transmitting smell signals to the brain.
2.1 Supporting cells:
- ↳ Surround & provide structural support to the ORNs.
3.1 Basal cells: (stem cells)
- ↳ Can differentiate into new olfactory receptor neurons, contributing to the regeneration of the olfactory epithelium.
- 2. Bowman's Glands (Olfactory glands):
- found in the Olfactory epithelium
- Secrete mucus that helps dissolve & trap odor molecules, facilitating their interaction with olfactory receptors.
- 3. Olfactory Bulb:
- ↳ A bulbous structure located at the base of the brain.
* the only sensory system that projects directly to the cortex of the telencephalon without a precortical relay in the thalamus.