CN 1: Olfactory Nerve (Scheme, Pathway, Clinical Relevance) | Neuroanatomy

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.).
- Olfactory Nerve | Radiology Key

Other sources used;
- Kozlowski, T. (2017). Memorix Anatomy: The Complete Study Guide. 2nd ed. Thieme Medical Publishers.

[yusu]

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[ibrohimrajabov]

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[RaminJPiran]

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All of them are incredible . Thanks alot

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[achieversvlog]

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[mohammadparsaalizadeh]

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[peterevelin]

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[marwanehab]

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[meeraswathi]

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[motiwala]

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[kyzzhankadyrkhan-pewc]

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[gps]

hi, is there a study you can share about olfactory fibers reaching the thalamus?

[rawankarim]

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[nikunjasaud]

Sir myself lost my smell power in a minor accident can its possible to recovery by any treatment?

[عمررمضان-عو]

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[НуржанарЯкупова-бс]

when will the next parts come out? looking forward to

[nadinkhatibb]

Please we need a video for facial nerve

[rakeshkornana]

Sir do videos for remaining cranial nerves