Cranial Nerve I: Olfactory Nerve

00:00 The first cranial nerve for you to understand is that of the olfactory nerve. It conveys just one functional component.

00:08 That is special afferent nerve impulses. This is going to be for olfaction. The sensory cells for olfaction are in the olfactory mucosa. You can see those identified in the illustration right in through this area.

00:26 This next slide allows you to zoom in and to gain a better appreciation for this special afferent functional component that’s associated with the olfactory nerve. At a higher view or higher magnification, you can better see the olfactory or sensory cells in the olfactory mucosa. Their axons will extend through the foramina in the cribriform plate as we see here. Then they’re going to synapse within the olfactory bulb region. Then, neurons from the olfactory bulb will travel in the olfactory tract toward the olfactory cortex as well as the amygdala.

01:14 The amygdala is a very important structure in connecting an emotional response to olfaction or smell.

01:23 A clinical consideration with respect to olfactory nerve I, if there’s damage to this pathway, the individual could have impairment or even a loss of smell and this is termed anosmia.

01:38 Some clinical considerations that may lead to an impairment of smell are as follows. Infection of the sinuses, sinusitis.

01:50 Hay fever can impair our sense of smell. Influenza, a viral infection, can as well. Common colds interfere with our sense of smell. Obstructions of the nasal passages, perhaps polyps or tumors developing.

02:10 There are some additional causes that may also lead to impairment of smell.