Olfaction 9.5

Question 1

Why is olfaction important?

Answer 1

1. Protection from noxious stimuli, poisons, unknown substances
2. Avoidance behaviours

Question 2

Is olfaction a vital sense?

Answer 2

Not for humans
It can be vital for some newborn species (nest bound animals identify the mammary gland of their mother)

Question 3

Sensory receptors are know as ___ and are located in ____ of ______

Answer 3

olfactory receptors that are located in olfactory epithelium of nasal cavity

Question 4

What are the cell type in the olfactory epithelium?

Answer 4

Olfactory receptor cell, supporting cell, basal cells
Mucus layer dissolves odorants

Question 5

Olfactory recpetor pathway

Answer 5

Transduction occurs at the olfactory cilia and first order neuron (olfactory neuron) (cranial nerve 1) extends to olfctory bulb (glomeruli and mitral cells). Mitral cells form the olfactory tract and the pathway to the olfactory cortex is ipsilateral. There is no relay at the thalumus.
Olfactory tract projects to other pathways (limbic system)

Question 6

Hyposmia

Answer 6

Reduced ability to smell
Loss of olfactory cells with age
Associated factors: Obesity, head trauma, viral overload (Covid19)

Question 7

Anosmia

Answer 7

Loss of smell (temporary or permanent)
Temp: thick mucus, allergies, smoking, viral load (covid19)
Perm: head trauma, brain injury, epilepsy, brain surgery

Question 8

What type of sense are Gustation and olfaction?

Answer 8

chemical senses