Understanding Accessory Organs of the Skin

Hello again. The purpose of this lab lecture is to really focus our attention on the accessory organs of the epidermis. So we are going to go over specific substructures of the accessory organs that we didn't talk about in lecture. With that said, please take a moment to take a look at your hit list and make sure you can identify all of the different structures that are on the hit list. Your connect activities for this week will help you to identify those structures that you will need to identify on the lab exam. So the three different accessory organs that we are going to focus on and their associated structures are nails, hairs, and glands. When it comes to the nails first, what I want you to remember is that the nail itself is derived from the stratum corneum, the most superficial layer. Beyond that, let's identify the structures of the nail. What you can see, with the exception of the free edge, the part that is not attached to the rest of your skin, all of this part of the nail that we can see is called the nail body, also known as the nail plate. So nail body and nail plate are one in the same. Attached to that you have the free edge. This is the edge that is still part of the nail, but it is not connected on the inferior side. And so that would be the free edge, and that's the part that tends to grow out of various lengths on different people, as long as you don't, for however long you don't cut them. Within the nail body, you will also see the lanula. Notice that you have this white part of your nail, and it helps if you don't have nail polish on your nails right now, you can take a look at your nails and identify these different structures. The lanula is white not because the stratum corneum is thicker, but the stratum basale, the deepest layer of the epidermis, is actually thicker. So you might remember that within the dermis, that's where you start to have your capillaries, that the epidermis and all of the strata that you have within the epidermis is avascular. But the deeper capillaries that you have within the dermis and the hypodermis, those are masked in the lanula portion of the nail because the stratum basale is thicker. there. So that's why it looks like it's white. You just can't see the pink undertones that would come from the capillaries. On either side of the nail, you have the borders. So let me just show you here specifically and here. That is called the nail folds. So those are the lateral borders of the nail. Where the nail dives down and and couples with those nail folds, that is called the nail groove. So you have lateral nail grooves. Technically, you also have a nail groove that is proximal to your body, but the nail grooves we want to identify are on the sides. So nail groove and then nail groove. Lateral to the nail grooves, again, are going to be the nail folds. So if we were to cut open a digit and look inside, we could see the rest of the nail structures. The nail has three major parts, two of which we've already identified. We have our free edge, we have the nail body, which also has the lanula, but deep to the living tissue, we have our nail root. So deep to the skin, we have our nail root. Surrounding the nail root and deep to all of the rest of the nail, we have this thickened layer of living cells. And that thickened layer of living cells is called the nail matrix. So it's going to provide for growth and eventually those cells will die and become part of the nail. But all around the nail you find the nail matrix. Now there's a couple different places that we have cuticle. We normally think about the cuticle that is on top of the nail. And that cuticle is called the eponychium. Let me go ahead and take you a step back. I should have identified it here. eponychium, that is the cuticle that you have here. In addition to cuticle above the nail, also below the free edge, so just below the free edge, you also have another cuticle. Where the free edge meets the tissue there, that is called the hyponychium. You might now think hypo below. So again, going back, eponychium on top, that's the cuticle above the lanula. and the hyponychium is below the free edge. Again, this is thickened corneum that we find here. So thickened corneum makes the hyponychium, and the eponychium is made of thickened corneum as well. Moving on to the hair. Our hair, you might remember, we can divide into three different regions. I called them zones in lecture, but if I wanted the specific region of a hair, that's what I would use on a lab exam. So these different regions, we have the hair bulb. So that is going to be the deepest portion. So here and here. The difference between these two structures is that the hair bulb is the deepest portion. structures that you're seeing on the model is this is the complete structure. So you're seeing all of the superficial parts of the hair. This one has been cut open so you can see the inner parts or the deepest parts of the hair. So that's the difference between these different structures so that you're aware. So again, at the very deepest portion, we have our hair bulb. We then have our hair, sorry, we're showing the hair bulb there again. The hair root is going to be superficial to the bulb, but everything deep. to the apical surface. And then we have our hair shaft. So the hair shaft is all of the region that is exposed outside of the body. Please note, you see that these are keratinocytes, the ones that you're going to have outside. So within the hair shaft will be dead. So it's essentially just keratin that you see outside of your scalp. The hair bulbs are going to dive deep. So some of these will be in the dermis, some of the... some of them will be as deep as in the hypodermis as well. Focusing on the hair bulb, we're going to find that there's several different parts. You might remember that we had that cell matrix or the nail matrix that provided living cells that eventually provided for the nail. In the same way we have living cells that provide for the hair bulb. as well. So the hair matrix is going to be all of this dark portion of the bulb. So I'm just going to highlight that here. So all of this is the hair matrix. So this is where the live cells are which can go through mitosis and provide for hair growth. Deep to that, and let me just watch my tracing, we have this invagination or kind of papilla. So this nipple-like projection that we see on the inside, that is called the hair papilla. Remember, papilla with an A is singular. If we add an E on top of that, it is papillae, which is plural. And what we're going to find in there, that would be your blood vessels, your nerves, connective tissue. All of that is within this region right here, the hair papilla. The hair root, that's where we can identify different layers within the actual hair follicle. So all of this is within the skin, but what we can identify are these different structures, the medulla, the cortex, and the cuticle. When I think medulla, I think most middle. the medulla is the most inner core of the hair root. Notice we are above the bulb here and above the papilla. So we're specifically within the root here. That's where we start the medulla. The middle layer is called the cortex, and so that is going to have a harder extracellular matrix, and it also contains cells. Just to come back to the medulla previously, that one's softer, and that has more keratin within it. I do not need you to know necessarily exactly what's in each layer, but at least to identify the individual structures. So we go medulla, this layer right here that we see, that is superficial to the medulla is the cortex and then finally the very outer layer is going to be the cuticle so that is the coating of the hair once you have that cuticle layer most of what you're going to see again on your scalp is dead But what you can do if you want to try and make your hair look nicer is you can use various things to smooth out That cuticle and to coat it and make it look smoother. So that's essentially what you're doing with your hair It's really hard to actually repair your hair that is present outside of your body The muscles that we associate with the hair, you might remember this from the lecture, is the erector pili muscle. So here's an erector pili muscle here associated with this hair follicle. Here's an erector pili muscle here associated with this hair follicle. We don't have any control over this. I mentioned in lecture that this will be triggered to contract, maybe due to temperature or stress or fear. And so it's an involuntary response. We often associate it when it comes to stress or fear with our fight or flight response. We'll get to learn exactly what that fight or flight response is in relation to the nervous system when we get to the nervous system lecture. So next up we have the glands. We have two major categories of glands that we want to be aware of. One for sweat and one for oil. So for the different exocrine glands we're covering, again sweat and oil, the sweat glands are collectively called the pseudoriferous glands. So that's pseudoriferous, it's spelled with an o. Those are the sweat glands. In addition to the pseudoriferous glands, we have our oil glands, which are the holocrine glands. When we get to the holocrine glands, we will focus on specifically naming the holocrine glands the sebaceous glands because they secrete sebum, which is oil. So secrete sebum. When it comes to our sweat in the pseudoriferous glands, there's actually different types of sweat that can be produced. So there's two major categories of sweat glands based on the type of sweat that they produce. And when I say the sweat that they produce, when you actually look at that sweat, not that you would be able to see it, but when you actually look at that sweat, you can actually see that sweat. So when I say the sweat that they produce, when you actually look at that sweat, not that you would be able to see it, but when you actually look at that sweat, you can see this, but what is inside of that sweat can either be mostly water or have additional things like lipids and proteins. We talked a little bit about this and how the very outside of your skin is really delicious for bacteria because you have all these dead skin cells with all of this cell membrane and cellular components that the body doesn't need. So the bacteria tends to feed off of that and thrive on the outside of your skin. Well, you might imagine too that if we have a specific type of sweat that is going to be secreting proteins and lipids, that bacteria might also like that as well. Anywhere where we have bacteria metabolism taking place, we can have things like infection, like acne is usually due to bacteria growth or blocked pores. And we can have odor, which is associated with certain sweat glands, which we'll get to in a second. The two major categories of pseudorific sweat glands are the mericrine-ecrine, which are going to be associated with mostly water that they secrete, and then the apocrine glands, which are going to secrete not just water, but lipids and proteins too. So first focusing on the pseudorifus or sweat glands, we have our mericrine-ecrine. You can use one name over the other. I tend to always put them together. It just helps me to remember this category a little bit more. As a reminder, they are going to be secreting mostly water. And they secrete this not through the process of osmosis, but as a gland, rather through the process of exocytosis. So that will be these glands that you see here in white. Please note that this is a whole gland and the entire structure that you can see superficially and this would be the same type of gland, American Ekron gland, same as here, but the exception is that they've cut these ones open. So all of these here in white are the American Ekron glands. Now we're going to find that you can actually find American Ekron glands in both thin skin and thick skin. However, where they're most numerous, where you're going to see them in abundance, are in places where you have thicker skin or tend to sweat more. So your forehead, palms of the feet, or palms of the hands, excuse me, soles of the feet, In these areas, when you tend to get nervous or stressed, we can feel that difference because you have a lot of sweatiness in those areas. And specifically what is releasing that sweat is the mericrine-ecrine glands. Now, because it's just water, we don't tend to have that sweat attract a lot of sweat. bacteria. So that sweat, even though it might be abundant, is not going to be necessarily very smelly. So American eccrine gland, what I want you to associate with this gland, they're secreting mostly water through the process of exocytosis and we can find them in thin skin and thick skin. But again, they'll probably be most abundant in areas where you tend to sweat a lot. So like the forehead and the palms of the hands and the soles of the feet. You'll also find that when it comes to the actual gland itself, that coiled tube tends to be, when you think of glands, you might think of those cuboidal cells. The gland for the most part is going to be simple cuboidal. Sometimes the ducts can be stratified cuboidal, but it depends on the gland when we talk about these various glands today. All right, so in addition to the merocrine-echoen gland, we also have the apocrine gland. The apocrine gland is a little bit bigger, so I want you to notice it's represented here in a different color. You're also seeing it sliced open so you can see the internal parts. It is larger than the merocrine-echoen gland, but it is still a coiled tube just like you saw with the merocrine-echoen gland. In addition to the size, one of the major differences between the merocrine-echoen glands and the apocrine is what it secretes. Instead of just water, what you're essentially secreting here is oils, the lipids, and proteins. And this oiliness, the lipids specifically, and the proteins are again secreted. the process of exocytosis. But here's where the odor comes into play. So you're secreting this thick essential, essentially a bacteria food from these particular glands. They are often going to be associated with hair follicles and where you often find them is in places that you might associate with puberty. So you might remember that you're going to have that terminal hair start to form in these auxiliary pubic anal regions after puberty. Well, in addition to that, you're going to also activate these apocrine glands. These apocrine glands will then secrete this delicious bacteria food, essentially the proteins and the lipids, and that's going to lead to the body odor that you experience in these places. So in addition to the pheromones that you're secreting during puberty, you're also secreting the apocrine stuff, so the proteins and the lipids. Now here's the difference you might notice of these regions. None of these are going to be thick skin regions. So we're not talking about the palms, we're not talking about the soles of the feet. All of these are thin skin regions. So we specifically find the apocrine glands in thin skin. So coming back, you want to note that it is larger. So I'm just going to write larger, but know that it's larger than the American eccrine glands. It's usually associated with hair, not always, but usually. It secretes lipids and proteins, so oils or lipids and proteins, and it especially does this after puberty. And what that leads to Sorry, my cursor is going out of control today. That leads to bacteria growth in those areas, which leads to body odor in those areas. And then finally, in those areas, we have not thick skin, but thin skin. So under the umbrella of the apricot glands, remember they secrete essentially lipids and proteins. We have some modified versions of the apricot gland within the body. One of those versions is the cerumenous gland. The cerumenous gland secretes cerumen. And what is cerumen? Cerumen is earwax. Earwax is a modified form of lipids and proteins. More specifically, what you're going to see is sebum, which is the oil or the lipid components, and the keratinocytes. The keratinocytes are dead, so most of this is going to be keratinocytes. but that sebum and the keratinocytes, or what's left of them, comes together to make the earwax that you experience. So again, the anatomical term for earwax is cerumen, and ceruminous glands are modified apocrine glands, which secrete that earwax. In addition to the ceruminous glands, another modified apocrine gland that we have is the mammary glands. you know that you very likely know that this is triggered by hormones, usually at the end of pregnancy and after pregnancy. Males are also capable of having the mammary gland secrete breast milk. However, that's usually associated with some kind of hormonal imbalance or some kind of addition of hormones to their body. So again, these are modified abracanth sweat glands. The difference is, of course, you're secreting proteins and lipids here, if you think about it, but in the form of breast milk instead. So coming back to our chart, just note that you have two rare types. You have your cerumenous glands and you have your mammary glands fall under this category. Sorry, it's acting up today. All right, the final category we're going to cover is the holocrine glands, again, also known as the sebaceous glands. And they secrete sebum. Sebum is oil. So for the holocrene glands, again we're focusing on the sebaceous glands. Oil is what they're secreting. Usually these are associated again with our hair follicles. So let me show you what those look like. Those are these blue structures. you're seeing directly attached to the hair follicle and they are within the dermis of the skin now again what's going to help to activate these sebaceous glands it's usually going to be puberty and the hormones that are associated with puberty you can have clogging of the ducts where the sebum would be secreted or you can have bacterial infection two of these things can lead to inflammation and essentially acne. So sebaceous glands are usually what cause acne. Again, either blocked ducts or pores or bacterial infection causes that. So let's go ahead and add this final part to the chart. Our sebaceous glands secrete sebum like I mentioned. They lubricate the hair and the skin. and they're usually activated by hormones. So that is it for our lab lecture. Again, please take a look back at the hit list and make sure you can identify all of the different structures that you are responsible for. I do recommend checking out my lab model recordings at the very end of this module to give you an idea of what those different structures might look like that I didn't cover in this lab lecture. Feel free to reach out if you have any questions.

With that said, please take a moment to take a look at your hit list and make sure you can identify all of the different structures that are on the hit list. Your connect activities for this week will help you to identify those structures that you will need to identify on the lab exam. So the three different accessory organs that we are going to focus on and their associated structures are nails, hairs, and glands.

When it comes to the nails first, what I want you to remember is that the nail itself is derived from the stratum corneum, the most superficial layer. Beyond that, let's identify the structures of the nail. What you can see, with the exception of the free edge, the part that is not attached to the rest of your skin, all of this part of the nail that we can see is called the nail body, also known as the nail plate. So nail body and nail plate are one in the same. Attached to that you have the free edge.

This is the edge that is still part of the nail, but it is not connected on the inferior side. And so that would be the free edge, and that's the part that tends to grow out of various lengths on different people, as long as you don't, for however long you don't cut them. Within the nail body, you will also see the lanula.

Notice that you have this white part of your nail, and it helps if you don't have nail polish on your nails right now, you can take a look at your nails and identify these different structures. The lanula is white not because the stratum corneum is thicker, but the stratum basale, the deepest layer of the epidermis, is actually thicker. So you might remember that within the dermis, that's where you start to have your capillaries, that the epidermis and all of the strata that you have within the epidermis is avascular.

But the deeper capillaries that you have within the dermis and the hypodermis, those are masked in the lanula portion of the nail because the stratum basale is thicker. there. So that's why it looks like it's white. You just can't see the pink undertones that would come from the capillaries.

On either side of the nail, you have the borders. So let me just show you here specifically and here. That is called the nail folds. So those are the lateral borders of the nail. Where the nail dives down and and couples with those nail folds, that is called the nail groove.

So you have lateral nail grooves. Technically, you also have a nail groove that is proximal to your body, but the nail grooves we want to identify are on the sides. So nail groove and then nail groove. Lateral to the nail grooves, again, are going to be the nail folds.

So if we were to cut open a digit and look inside, we could see the rest of the nail structures. The nail has three major parts, two of which we've already identified. We have our free edge, we have the nail body, which also has the lanula, but deep to the living tissue, we have our nail root.

So deep to the skin, we have our nail root. Surrounding the nail root and deep to all of the rest of the nail, we have this thickened layer of living cells. And that thickened layer of living cells is called the nail matrix.

So it's going to provide for growth and eventually those cells will die and become part of the nail. But all around the nail you find the nail matrix. Now there's a couple different places that we have cuticle. We normally think about the cuticle that is on top of the nail. And that cuticle is called the eponychium.

Let me go ahead and take you a step back. I should have identified it here. eponychium, that is the cuticle that you have here.

In addition to cuticle above the nail, also below the free edge, so just below the free edge, you also have another cuticle. Where the free edge meets the tissue there, that is called the hyponychium. You might now think hypo below.

So again, going back, eponychium on top, that's the cuticle above the lanula. and the hyponychium is below the free edge. Again, this is thickened corneum that we find here.

So thickened corneum makes the hyponychium, and the eponychium is made of thickened corneum as well. Moving on to the hair. Our hair, you might remember, we can divide into three different regions.

I called them zones in lecture, but if I wanted the specific region of a hair, that's what I would use on a lab exam. So these different regions, we have the hair bulb. So that is going to be the deepest portion. So here and here. The difference between these two structures is that the hair bulb is the deepest portion.

structures that you're seeing on the model is this is the complete structure. So you're seeing all of the superficial parts of the hair. This one has been cut open so you can see the inner parts or the deepest parts of the hair. So that's the difference between these different structures so that you're aware. So again, at the very deepest portion, we have our hair bulb.

We then have our hair, sorry, we're showing the hair bulb there again. The hair root is going to be superficial to the bulb, but everything deep. to the apical surface.

And then we have our hair shaft. So the hair shaft is all of the region that is exposed outside of the body. Please note, you see that these are keratinocytes, the ones that you're going to have outside. So within the hair shaft will be dead.

So it's essentially just keratin that you see outside of your scalp. The hair bulbs are going to dive deep. So some of these will be in the dermis, some of the...

some of them will be as deep as in the hypodermis as well. Focusing on the hair bulb, we're going to find that there's several different parts. You might remember that we had that cell matrix or the nail matrix that provided living cells that eventually provided for the nail. In the same way we have living cells that provide for the hair bulb. as well.

So the hair matrix is going to be all of this dark portion of the bulb. So I'm just going to highlight that here. So all of this is the hair matrix.

So this is where the live cells are which can go through mitosis and provide for hair growth. Deep to that, and let me just watch my tracing, we have this invagination or kind of papilla. So this nipple-like projection that we see on the inside, that is called the hair papilla. Remember, papilla with an A is singular. If we add an E on top of that, it is papillae, which is plural.

And what we're going to find in there, that would be your blood vessels, your nerves, connective tissue. All of that is within this region right here, the hair papilla. The hair root, that's where we can identify different layers within the actual hair follicle. So all of this is within the skin, but what we can identify are these different structures, the medulla, the cortex, and the cuticle. When I think medulla, I think most middle.

the medulla is the most inner core of the hair root. Notice we are above the bulb here and above the papilla. So we're specifically within the root here.

That's where we start the medulla. The middle layer is called the cortex, and so that is going to have a harder extracellular matrix, and it also contains cells. Just to come back to the medulla previously, that one's softer, and that has more keratin within it.

I do not need you to know necessarily exactly what's in each layer, but at least to identify the individual structures. So we go medulla, this layer right here that we see, that is superficial to the medulla is the cortex and then finally the very outer layer is going to be the cuticle so that is the coating of the hair once you have that cuticle layer most of what you're going to see again on your scalp is dead But what you can do if you want to try and make your hair look nicer is you can use various things to smooth out That cuticle and to coat it and make it look smoother. So that's essentially what you're doing with your hair It's really hard to actually repair your hair that is present outside of your body The muscles that we associate with the hair, you might remember this from the lecture, is the erector pili muscle.

So here's an erector pili muscle here associated with this hair follicle. Here's an erector pili muscle here associated with this hair follicle. We don't have any control over this. I mentioned in lecture that this will be triggered to contract, maybe due to temperature or stress or fear.

And so it's an involuntary response. We often associate it when it comes to stress or fear with our fight or flight response. We'll get to learn exactly what that fight or flight response is in relation to the nervous system when we get to the nervous system lecture.

So next up we have the glands. We have two major categories of glands that we want to be aware of. One for sweat and one for oil.

So for the different exocrine glands we're covering, again sweat and oil, the sweat glands are collectively called the pseudoriferous glands. So that's pseudoriferous, it's spelled with an o. Those are the sweat glands. In addition to the pseudoriferous glands, we have our oil glands, which are the holocrine glands. When we get to the holocrine glands, we will focus on specifically naming the holocrine glands the sebaceous glands because they secrete sebum, which is oil.

So secrete sebum. When it comes to our sweat in the pseudoriferous glands, there's actually different types of sweat that can be produced. So there's two major categories of sweat glands based on the type of sweat that they produce.

And when I say the sweat that they produce, when you actually look at that sweat, not that you would be able to see it, but when you actually look at that sweat, you can actually see that sweat. So when I say the sweat that they produce, when you actually look at that sweat, not that you would be able to see it, but when you actually look at that sweat, you can see this, but what is inside of that sweat can either be mostly water or have additional things like lipids and proteins. We talked a little bit about this and how the very outside of your skin is really delicious for bacteria because you have all these dead skin cells with all of this cell membrane and cellular components that the body doesn't need. So the bacteria tends to feed off of that and thrive on the outside of your skin. Well, you might imagine too that if we have a specific type of sweat that is going to be secreting proteins and lipids, that bacteria might also like that as well.

Anywhere where we have bacteria metabolism taking place, we can have things like infection, like acne is usually due to bacteria growth or blocked pores. And we can have odor, which is associated with certain sweat glands, which we'll get to in a second. The two major categories of pseudorific sweat glands are the mericrine-ecrine, which are going to be associated with mostly water that they secrete, and then the apocrine glands, which are going to secrete not just water, but lipids and proteins too.

So first focusing on the pseudorifus or sweat glands, we have our mericrine-ecrine. You can use one name over the other. I tend to always put them together. It just helps me to remember this category a little bit more. As a reminder, they are going to be secreting mostly water.

And they secrete this not through the process of osmosis, but as a gland, rather through the process of exocytosis. So that will be these glands that you see here in white. Please note that this is a whole gland and the entire structure that you can see superficially and this would be the same type of gland, American Ekron gland, same as here, but the exception is that they've cut these ones open. So all of these here in white are the American Ekron glands. Now we're going to find that you can actually find American Ekron glands in both thin skin and thick skin.

However, where they're most numerous, where you're going to see them in abundance, are in places where you have thicker skin or tend to sweat more. So your forehead, palms of the feet, or palms of the hands, excuse me, soles of the feet, In these areas, when you tend to get nervous or stressed, we can feel that difference because you have a lot of sweatiness in those areas. And specifically what is releasing that sweat is the mericrine-ecrine glands.

Now, because it's just water, we don't tend to have that sweat attract a lot of sweat. bacteria. So that sweat, even though it might be abundant, is not going to be necessarily very smelly.

So American eccrine gland, what I want you to associate with this gland, they're secreting mostly water through the process of exocytosis and we can find them in thin skin and thick skin. But again, they'll probably be most abundant in areas where you tend to sweat a lot. So like the forehead and the palms of the hands and the soles of the feet.

You'll also find that when it comes to the actual gland itself, that coiled tube tends to be, when you think of glands, you might think of those cuboidal cells. The gland for the most part is going to be simple cuboidal. Sometimes the ducts can be stratified cuboidal, but it depends on the gland when we talk about these various glands today. All right, so in addition to the merocrine-echoen gland, we also have the apocrine gland.

The apocrine gland is a little bit bigger, so I want you to notice it's represented here in a different color. You're also seeing it sliced open so you can see the internal parts. It is larger than the merocrine-echoen gland, but it is still a coiled tube just like you saw with the merocrine-echoen gland. In addition to the size, one of the major differences between the merocrine-echoen glands and the apocrine is what it secretes. Instead of just water, what you're essentially secreting here is oils, the lipids, and proteins.

And this oiliness, the lipids specifically, and the proteins are again secreted. the process of exocytosis. But here's where the odor comes into play. So you're secreting this thick essential, essentially a bacteria food from these particular glands.

They are often going to be associated with hair follicles and where you often find them is in places that you might associate with puberty. So you might remember that you're going to have that terminal hair start to form in these auxiliary pubic anal regions after puberty. Well, in addition to that, you're going to also activate these apocrine glands.

These apocrine glands will then secrete this delicious bacteria food, essentially the proteins and the lipids, and that's going to lead to the body odor that you experience in these places. So in addition to the pheromones that you're secreting during puberty, you're also secreting the apocrine stuff, so the proteins and the lipids. Now here's the difference you might notice of these regions.

None of these are going to be thick skin regions. So we're not talking about the palms, we're not talking about the soles of the feet. All of these are thin skin regions.

So we specifically find the apocrine glands in thin skin. So coming back, you want to note that it is larger. So I'm just going to write larger, but know that it's larger than the American eccrine glands.

It's usually associated with hair, not always, but usually. It secretes lipids and proteins, so oils or lipids and proteins, and it especially does this after puberty. And what that leads to Sorry, my cursor is going out of control today. That leads to bacteria growth in those areas, which leads to body odor in those areas. And then finally, in those areas, we have not thick skin, but thin skin.

So under the umbrella of the apricot glands, remember they secrete essentially lipids and proteins. We have some modified versions of the apricot gland within the body. One of those versions is the cerumenous gland. The cerumenous gland secretes cerumen.

And what is cerumen? Cerumen is earwax. Earwax is a modified form of lipids and proteins. More specifically, what you're going to see is sebum, which is the oil or the lipid components, and the keratinocytes. The keratinocytes are dead, so most of this is going to be keratinocytes.

but that sebum and the keratinocytes, or what's left of them, comes together to make the earwax that you experience. So again, the anatomical term for earwax is cerumen, and ceruminous glands are modified apocrine glands, which secrete that earwax. In addition to the ceruminous glands, another modified apocrine gland that we have is the mammary glands. you know that you very likely know that this is triggered by hormones, usually at the end of pregnancy and after pregnancy. Males are also capable of having the mammary gland secrete breast milk.

However, that's usually associated with some kind of hormonal imbalance or some kind of addition of hormones to their body. So again, these are modified abracanth sweat glands. The difference is, of course, you're secreting proteins and lipids here, if you think about it, but in the form of breast milk instead. So coming back to our chart, just note that you have two rare types.

You have your cerumenous glands and you have your mammary glands fall under this category. Sorry, it's acting up today. All right, the final category we're going to cover is the holocrine glands, again, also known as the sebaceous glands. And they secrete sebum.

Sebum is oil. So for the holocrene glands, again we're focusing on the sebaceous glands. Oil is what they're secreting.

Usually these are associated again with our hair follicles. So let me show you what those look like. Those are these blue structures. you're seeing directly attached to the hair follicle and they are within the dermis of the skin now again what's going to help to activate these sebaceous glands it's usually going to be puberty and the hormones that are associated with puberty you can have clogging of the ducts where the sebum would be secreted or you can have bacterial infection two of these things can lead to inflammation and essentially acne. So sebaceous glands are usually what cause acne.

Again, either blocked ducts or pores or bacterial infection causes that. So let's go ahead and add this final part to the chart. Our sebaceous glands secrete sebum like I mentioned. They lubricate the hair and the skin.

and they're usually activated by hormones. So that is it for our lab lecture. Again, please take a look back at the hit list and make sure you can identify all of the different structures that you are responsible for.

I do recommend checking out my lab model recordings at the very end of this module to give you an idea of what those different structures might look like that I didn't cover in this lab lecture. Feel free to reach out if you have any questions.

Transcript for:Understanding Accessory Organs of the Skin

Transcript for:
Understanding Accessory Organs of the Skin