Olfaction (Nursing)

00:01 Now we're going to look at some very specialized anatomy.

00:05 We're going to look at the anatomy of what we call the special senses.

00:10 So there are a lot of ways of classifying the nervous system.

00:14 And one way is to think of the sensory division.

00:17 In some ways, we think of general sensation as being the basic types of sensation we think of in everyday life, like the sensation of touch, temperature, things like that.

00:28 But then, we also have what are called special senses, fairly unique ones such like vision and taste.

00:36 And then the other major division of the nervous system, in contrast to sensory would be motor.

00:42 So carrying out actions on muscles.

00:46 Special senses include olfaction, which is our fancy word for smelling, taste, hearing and equilibrium, which we combine here because they're anatomically located in the same region, and vision.

01:05 Will start with olfaction, or smelling.

01:09 So the uppermost portions of the nasal cavity, have a different type of epithelium than the surrounding nasal cavity epithelium.

01:20 And we call it olfactory epithelium.

01:23 And in the respiratory section, when we talked about upper respiratory tract, we learned that there are these conchae turbinates that helped turbulent flow reach the top parts of the nasal cavity, so it can be exposed to this olfactory epithelium.

01:41 And within this olfactory epithelium, we have various receptor cells spread throughout.

01:48 And they have little extensions called dendrites that actually go out onto the surface of this olfactory epithelium.

01:56 And what they do is they look for basically molecules to smell.

02:02 And these olfactory receptor cells are actually the cranial nerves that will have axons going back up through the bone.

02:13 And this portion, they're called the Cribriform plate.

02:17 Cribriform, because they have a bunch of tiny little holes for these axons to go through, and eventually reach something inside the cranial cavity called the olfactory bulb, where they'll synapse and then start attract back towards the deeper parts of the brain.

02:35 And this is essentially how we get the sensation of taste.

02:41 And there's all these odors that can be sensed because essentially, air gets dissolved in a thin layer of fluid that sits on top of the olfactory epithelium.

02:52 And these dendrites basically sample that dissolved fluid for little odor molecules.

02:59 And that's the process of sensing these tiny little different odors that are then processed backwards in the brain.

03:08 So here we have a zoomed out view where we see the olfactory epithelium.

03:12 We have a very thin bone there, the cribriform plate that goes up to the olfactory bulb, and then it goes backwards towards the brain via the olfactory tract, until eventually reaches the primary olfactory areas of the cerebrum, where smell is actually processed.