CN 1: Olfactory Nerve (DETAILED Scheme + Animation)
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 Published On Feb 20, 2023

Content:
0:00 Introduction
00:49 Olfactory Nerve Scheme
02:43 Olfactory Nerve and Epithelium
04:11 How Do We Detect Smells?
06:14 Mechanism of Odorant Signal Transduction
07:20 Olfactory Nerve
08:00 Olfactory Bulb
09:27 Olfactory Pathway
10:12 Lateral Olfactory Stria
14:13 Medial Olfactory Stria
14:40 Intermediate Olfactory Stria
15:15 Anosmia and Dysosmia
18:29 Recap
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Olfactory Scheme / Overview:
- Smell - Olfactory Nerves - Olfactory Bulb - Olfactory Tract - Olfactory Trigone - Lateral Stria, Medial Stria and Intermediate stria

Olfactory Epithelium:
- Pseudostratified Columnar epithelium (supporting cells)
- Consists of: Basal Cells, Sustentacular Cells, Olfactory gland cells (Bowmans glands), Olfactory receptor neurons
- Olfactory neurons are bipolar neurons

How we detect smell:
- Odorants enters nasal cavity through either nasal opening or nasopharynx.

Olfactory Neuron:
- Dendrites detect smell through a g-protein couples membrane receptor.
- Signals pass through the cell body and axon
- Axons form nerve bundles (fila olfactoria)

Olfactory Bulb (bulbus olfactorius):
- Mitral Cells
- Olfactory Glomerulus (glomeruli)
- Tufted Cells
- Amacrine Granular Cells
- Periglomerular Cells

Olfactory Pathway:
- Olfactory Bulb to the Olfactory Tract
- When the tract gets closer to the olfactory tract, it widens as the Olfactory Trigone (trigonum olfactorium) and divides into Lateral olfactory stria, Medial olfactory stria and intermediate olfactory stria.

Lateral Olfactory Stria (stria olfactoria lateralis)
- Towards Primary Olfactory Cortex, which sends information to secondary olfactory cortex

Medial Olfactory Stria (stria olfactoria medialis):
- Go towards the subcallosal gyrus (part of limbic system)

Intermediate Olfactory Stria (stria olfactoria intemedialis):
- Goes towards the olfactory Tubercle (part of the limbic system and the rewards system)

Clinical Relevance:
- Anosmia: Temporary or permanent loss of the sense of smell
- Dysosmia: Distortion of the perception of smell
- Parosmia: Normal smell smell and taste unpleasant/disgusting
- Phantosmia: Detect smells that aren't really there in your envirnoment

Sources:
- Singh, I. (2017). Human neuroanatomy (10th ed.).
Helwany M, Bordoni B. Neuroanatomy, Cranial Nerve 1 (Olfactory) [Updated 2022 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-
- F.D. Raslau, I.T. Mark, A.P. Klein, J.L. Ulmer, V. Mathews and L.P. Mark
American Journal of Neuroradiology May 2015, 36 (5) 846-849
Kozlowski, T. (2017). Memorix Anatomy: The Complete Study Guide. 2nd ed. Thieme Medical Publishers.

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