Special senses : Taste and smell and smell- Gustation and Olfaction

Question 1

What are the olfactory sensory neurons?

Answer 1

• Located in the olfactory mucosa or epithelium
• Consists of :
• Olfactory sensory neurons
• Supporting cells = Help produce mucus
• Basal cells - source of new receptor cells
• Dendritic end - olfactory knobs, Cilia
• Odorants bind to receptors on olfactory cilia initiate signal transduction
• Olfactory epithelium occupies an area 5cm 2

Question 2

Describe the cribriform plate of the ethmoid bone

Answer 2

• Has tiny perforations through which the olfactory filia (bundles of thin axons of olfactory bipolar neurons) pass
• The olfactory nerve (CN I) is forned of these bundles of axons
• Axons of the olfactory sensory neurons project through the cribriform plate into the olfactory bulb
• They sybapse onto second otfer olfactory neurones within a glomerulus
• Signals are then relayed via the olfactory tracts to different areas of the brain

Question 3

How do we tell the difference between different oodorant molecules?

Answer 3

• Each odorant is recognised by a unique combination of receptors. A single odorant can recognise multiple odorantsm and one odorant is recognised by a specific combination of different receptors.
• itracellular signalling mechanisms
• cAMP and IP3
• Sensory trasduction in olfaction. The olfactory binding protein carries odorant molecules to the cilia of the olfactory sensory neurons. Receptor-odorant complex is formed, which activates a G protein.

Question 4

What are some clinical conditions of the olfactory?

Answer 4

• Anosmia
• Hyposmia
• Damage to sensory neurons in olfactory mucosa due to trauma or infection
• 90% of parkinson’s disease will experience a reduced sense of smell (hyposmia) - this can be an early pre-motor sign of disease