on 1:07 apology likes in videos please make sure to subscribe to an appointment group for this videos please face what everyone plays like and even ask questions ask questions and post some interesting things including Alex and if it also change the quality settings to the highest ones better graphics in this video we’ll look at the inter commentary system an overview and I called the dermatology because dermatology is a field of medicine that focuses on the integumentary system I just want to call this a bit fancier now when we think of the integumentary system or dermatology we think of the skin that is the main component of the interplanetary system the skin is the largest organ in the human body it’s it’s average weight is about 4 to 5 kilograms the skin’s main function is to protect the interior of the body from the external environment in a whole it also has a role in the metabolism of vitamin D amongst other things here I’m drawing a person just to explain that our body it consists of basically two types of skin we have a thin skin and if you haven’t realized we have a thick skin for example the soles of your foot and the palm of your hands they’re much thicker and they’re less elastic they’re also hairless but for now we will focus on the thin skin so here we’re just zooming into the deltoid region and we’re looking at this person’s skin we’re looking at the different layers as well as the anatomy of the skin as you can see we have hairs coming out and other structures below it the skin is divided into two main layers the epidermis and the dermis the dermis can be divided further into the papillary layer and the reticular layer the papillary layer is important in forming our own unique fingerprints we have the third layer below the dermis called the hypodermis hypo as in below that is actually not part of the skin the hypodermis contains many adipose tissue adipose tissue are just fat tissue essentially so as mentioned the the papillary layer is responsible for forming our own unique unique fingerprints and this is because it contains dermal papillae these bumps of course there is a rich blood supply to the integumentary system but the vessels do not supply blood to the epidermis rather the blood vessels or rise from the dermis and supplies blood in the dermis in the dermis layer and only to the base of the epidermis layer so the top or middle of the epidermis don’t really get any blood at all and we’ll soon see what this means now the adipose tissue as mentioned is part of the hypodermis layer and it is to help in maintaining temperature homeostasis amongst other things and it’s basically fat tissue as I mentioned now the appendages of the skin are appendages that are to be found within skin structures these include the hair the hair root and hair follicle here where the hair comes from connected to the hair follicle we have sebaceous glands which secrete oil to lubricate and waterproof the skin and the hair we also find a crime glands around the dermis area and which will go up to the epidermis and these eccrine glands secrete are basically sweat glands and secrete sweat our sweat we find these everywhere in our body a good example is in the armpits then we have muscles that connect to the hair root or follicle which are the muscles responsible for pulling our hair for example when we have goose bumps and these muscles are known as erector pili muscles so those are the appendages of the skin we also have nerve structures in our skin as well which send information to the brain as well as from the brain these nerve structures include hair follicle receptors for our hair the lamellae corpuscle which are actually a type of nerve ending it’s a mechanoreceptor that is sensitive to vibration and pressure so when we feel pressure in our skin someone pushing down these lamellae corpuscles are activated then we have other free nerve endings that branch out all the way to the epidermis below the epidermis and these nerve endings include pain receptors for example now let’s talk a bit more about the epidermis layer the epidermis layer is not as simple as shown at the diagram and looks just like one layer but the epidermis layer actually consists of many layers it’s made up of squamous epithelial cells let’s have a look at each of these layers in the epidermis the epidermis is a vascular meaning it has no blood supply it consists of keratinized sheet of squamous epithelial epithelium remember we are looking at the epidermis layer now now the very top layer of the epidermis is known as a stratum corneum where we have 20 to 30 layers of dead cells these dead cells are known as keratinocytes which are keratin cells so basically on the top of our skin we have a dead cells so if we rub our skin now a flakes of dead cells will fly off now that was a very top of the f-b-i epidermis let’s look at the very bottom layer of the epidermis the very bottom layer of the epidermis is the stratum Vasily Vasily Vasilyevich avoiding cells actively dividing keratinocytes the keratin cells and these cells as they’re actively dividing they will begin moving up basically pushing up and pushing the dead cells out why are they actively dividing well it’s because there is some blood supply at the very base of the epidermis which is a stretch of basilar so with the blood supply it means that they can divide they are alive but as they move up they will slowly lose this blood supply and they will die there are other cells found within the APA within the stretch of man select such as melanocytes which are responsible for producing melanin which is responsible for the color of our skin then we have tactile cells also which are basically nerve endings for set for sensing things above the stratum basilar we have another layer known as a stretch of spinosa and this is where we have layers of keratinocytes with which are all connected by desmosomes desmosomes are basically junctions so here I’m drawing cells with black lines connected to each other these black lines represent desmosomes so they’re tightly packed we can also find dendritic cells here now dendritic cells are just basically part of the immune system responsible for taking up pathogens or destroying pathogens basically above the stratum spinosum we have another layer layer known as a stratum granulosa where we have layers of keratinocytes with the organ a with the organelles slowly being destroyed the degeneration of organelles and this is because there is no blood supply in in this layer essentially and so these black dots I’m drawing within the cell represents the organelles degrading and so as this moves up to the top layer the keratinocytes are already dead so as we just learned the epidermis of the thinset skin consists of four layers from the top distracted corneum granulosa Spinoza and Vasily below the basilar below the epidermis we have the dermis layer the highly vascularized layer the dermis consists of two layers itself the papillary layer which contains the the dermal papillae and also the popular papillary layer connects to the epidermis the papillary layer is important because it forms fingerprints due to these bumps here the dermal papillae the other layer is the reticular layer which is composed of connective tissue fibers this is a pretty dense area tightly packed cells so that was just we looked at an example of a thin skin just then of the deltoid right but we have two types of skins where the thin skin and the thick skin what is the difference well there’s actually not much difference the thin skin is hairy we have hair so we have hair follicle here and we also have a thin layer of adipose tissue of the hypodermis the thick layer is hairless it contains no hair and it has a thick layer of adipose tissue an example of a thick layer is the sole of our foot and we don’t find here there but the main difference that I looked that I want to explain is an anatomical point of view is that the epidermis layer it consists of five main layers instead of four so from the top we actually have the stretch of corneum destructiveness idiom stratum granulosum stratum spinosum and struct stratum vasily as you can see that and the additional layer is a stratum lucidum we don’t find the stratum lucidum in the thin skin hope that made sense so now let’s look at a hair follicles let’s learn a bit more about here so here I’m just going the hair the hair root coming up and the hair shop above our skin we have a blood vessel supplying the hair because the hair needs blood vessels to grow and the blood vessel is supplied from the hair root and it’s supplied from the hypodermis or just the billet on the base of the dermis this layer consists of many adipose tissue we have the hair shaft here the hair root the bottom and we have erector pili muscles connecting the hair root which are responsible for pulling the hair such as that when we have goose bumps or frightened we actually also find melanocytes cells within the hair root the melanocytes are remember are responsible for producing melanin for color and that’s why you can see the hair is color and the final thing that I want to point out is that connected to the hair root the hair follicle down here we have glands known as sebaceous glands which secrete oil the sebaceous gland is important because it lubricates the hair as well as the skin and also makes it waterproof I hope you enjoyed this overview of the interrogatory system please share comment like thank you all you