Hi. In this lesson, we'll be talking about the sensory system, which is the part of the nervous system that receives and processes sensory information. It's going to be our body's way of identifying what's out in the environment and going to give us the information necessary to construct our realities. So the first step of this is gonna be sensory reception, which is just the detection of some type of stimulus by sensory receptors. A sensory receptor is a type of nerve that responds to some stimuli and trans deuces. A response is either a graded or in action potential, and it should be noted that sensory receptors on lee respond to very specific stimuli for example, temperature within a certain range or ah, light of a very specific type. Now, sensory transducer, uh, ction is the conversion of that stimulus into some internal signal, like a graded or an action potential. So our sensory receptors air going to trans deuce the signals they get, and during transaction, these signals can actually be greatly amplified. Now the receptor potential is essentially a type of graded potential that's generated by the activation of sensory receptors, so thes grated potentials will either deep, polarized or hyper polarize theme membrane potential off these nerves. And that will either in lead to action potentials or in the case of hyper polarization, prevent action potentials and thes uh, you know, thes action potentials. It should be noted, are you know, acts potentials. Onley have It's like an all or nothing signal. They only have one signal that they can send. So the magnitude of these receptor potentials is going to be encoded in the frequency of action potentials that air issued and over time, sensory responses to a stimulus can change and we actually call that sensory adaptation. Now, here you can see a bunch of different types off sensory receptors and, uh, you know, they come in ah, wide variety of shapes and sizes is really the end. Take away here on what I want to point out is behind me how, for example, a sensory receptor will either d polarized or hyper polarized. So in the case of the pressure receptors in our skin that we use thio sense, different types of touch light pressure will actually deform these nerves and physically pull open channels that allow ions through so light pressure will, uh, slightly open the ion channel and allow just a little bit of, in this case sodium through, whereas a big pressure will cause a great D formation and allow a large amount of sodium to enter the cell and result in a greater deep polarization. So not every type of sensory receptor is going to work by some type of physical de formation that opens ion channels. But I think this conveys nicely the, uh, you know, the different ways in which magnitudes can be conveyed by, you know, the literal opening of channels. I mean, that's how these things are working. So once the information has been transducer, it has to be transmitted or sent to the central nervous system, and sensory neurons will actually carry this information to specific parts of the brain because of localization of function. Uh, there are specific areas dedicated to processing sound dedicated to processing, uh, visual stimulation. In fact, amongst visual stimulation, there's different areas that process different types of visual stimulation, like edge detection or motion. Now this all sums together into what you would call perception, which is our brain's way of taking the sensory information processing it and turning it into a meaningful representation of stimulus. So you know, the way you know we often think about the world is you know, I'm seeing the world around me when in actuality, that's not what's happening. What's happening is light is hitting the sensory receptors in your eyes and conveys various signals to them. And then that information is taken to the optic cortex, right, the or the visual cortex, and there it's processed, and then what you see as the world around you develops during that process. So, really, everything that you perceive as your reality is the world around you is more or less in your imagination when you really think about it, because it's just a construct in your mind and what you're perceiving is the world around. You could, in fact, be very different from what someone else perceives is the world around them. You know, one of the greatest examples that you can really give of this is that when we see images, we're actually seeing them upside down the way that light enters our eye and stimulates our sensory receptors. There. We actually end up with an image that's the upside down version of what's out in the world. Our brain is actually what takes that and flips it right side up. Just a nice illustration of how our minds air actually constructing what we consider our realities. Now with that, let's go ahead and flip the page light stuff, right?