protection (prevents loss of body fluids, inhibits invasion of bacteria, and filters out UV light rays; basically keeps insides in and outside out) The four types of membranes are: 1) cutaneous membranes; 2) serous membranes; 3) mucous membranes; and 4) synovial membranes. synovial membrane. group of membrane tissues that includes mucous, serous, and the cutaneous membranes cutaneous membrane dry membrane with 2 layers: epidermis and dermis a.k.a. Fat distribution changes as our bodies mature and age. ... cutaneous membrane. Figure 4. Layers of the Epidermis. As the name suggests, the stratum spinosum is spiny in appearance due to the protruding cell processes that join the cells via a structure called a desmosome. Where the fat is deposited and accumulates within the hypodermis depends on hormones (testosterone, estrogen, insulin, glucagon, leptin, and others), as well as genetic factors. This thin layer of cells is found only in the thick skin of the palms, soles, and digits. Recall that melanin is produced by cells called melanocytes, which are found scattered throughout the stratum basale of the epidermis. Although you may not typically think of the skin as an organ, it is in fact made of tissues that work together as a single structure to perform unique and critical functions. The stratum basale is a single layer of cells primarily made of basal cells. (credit: Klaus D. Peter). Treatment of this disorder usually involves addressing the symptoms, such as limiting UV light exposure to the skin and eyes. Within the papillary layer are fibroblasts, a small number of fat cells (adipocytes), and an abundance of capillary loops. All of the keratinocytes are produced from this single layer of cells, which are constantly going through mitosis to produce new cells. The reticular layer appears reticulated (net-like) due to a tight meshwork of fibers. Elastin fibers provide some elasticity to the skin, enabling movement. The edges of the lips are covered with reddish skin, sometimes called the vermilion border, and abundantly provided with sensitive nerve endings. EM × 2700. It contains blood and lymph vessels, nerves, and other structures, such as hair follicles and sweat glands. Report an issue . It's superficial epidermis is made up of squamous keratinizing epithelium. The cells in the stratum basale bond to the dermis via intertwining collagen fibers, referred to as the basement membrane. Chapter 4 Skin and Body Membranes 59 INTEGUMENTARY SYSTEM (SKIN) Basic Functions of the Skin 3. “Thick skin” is found only on the palms of the hands and the soles of the feet. The transitional area where the skin and mucous membrane meet: Term. The desmosomes interlock with each other and strengthen the bond between the cells. 0 times. Changes in lifestyle, specifically in diet and exercise, are the best ways to control body fat accumulation, especially when it reaches levels that increase the risk of heart disease and diabetes. Synovial membranes: Definition. The stratum basale (also called the stratum germinativum) is the deepest epidermal layer and attaches the epidermis to the basal lamina, below which lie the layers of the dermis. Both are made of connective tissue with fibers of collagen extending from one to the other, making the border between the two somewhat indistinct. In addition, the papillary layer contains phagocytes, defensive cells that help fight bacteria or other infections that have breached the skin. This dry, dead layer helps prevent the penetration of microbes and the dehydration of underlying tissues, and provides a mechanical protection against abrasion for the more delicate, underlying layers. It also has numerous sensory, and autonomic and sympathetic nerve fibers ensuring communication to and from the brain. A basal cell is a cuboidal-shaped stem cell that is a precursor of the keratinocytes of the epidermis. It is composed of keratinizing stratified squamous epithelium. Classify each of the protective factors listed below as an example of a chemical barrier (C), a biological barrier (B), or a mechanical (physical) barrier (M). It is interesting to note that the “spiny” nature of this layer is an artifact of the staining process. The dermis might be considered the “core” of the integumentary system (derma- = “skin”), as distinct from the epidermis (epi- = “upon” or “over”) and hypodermis (hypo- = “below”). View thisÂ, This ABC video follows the story of a pair of fraternal African-American twins, one of whom is albino. The entire layer is replaced during a period of about 4 weeks. A keratinocyte is a cell that manufactures and stores the protein keratin. Keratin is an intracellular fibrous protein that gives hair, nails, and skin their hardness and water-resistant properties. Collagen fibers provide structure and tensile strength, with strands of collagen extending into both the papillary layer and the hypodermis. This leads to a loss of color in patches (Figure 9). As new cells are formed, the existing cells are pushed superficially away from the stratum basale. The stratum lucidum is a smooth, seemingly translucent layer of the epidermis located just above the stratum granulosum and below the stratum corneum. Skin that has four layers of cells is referred to as “thin skin.” From deep to superficial, these layers are the stratum basale, stratum spinosum, stratum granulosum, and stratum corneum. The melanin is transferred into the keratinocytes via a cellular vesicle called a melanosome (Figure 7). The second is a melanocyte, a cell that produces the pigment melanin. Melanin gives hair and skin its color, and also helps protect the living cells of the epidermis from ultraviolet (UV) radiation damage. LM × 10. Although periodic accumulation of excess fat may have provided an evolutionary advantage to our ancestors, who experienced unpredictable bouts of famine, it is now becoming chronic and considered a major health threat. The second is a melanocyte, a cell that produces the pigment melanin. Melanin gives hair and skin its color, and also helps protect the living cells of the epidermis from ultraviolet (UV) radiation damage. Superficial epidermis is composed of keratinized stratified squamous epithelium III. As new keratinocytes are produced atop the stratum basale, the keratinocytes of the stratum spinosum are pushed into the stratum granulosum. The nuclei and other cell organelles disintegrate as the cells die, leaving behind the keratin, keratohyalin, and cell membranes that will form the stratum lucidum, the stratum corneum, and the accessory structures of hair and nails. AÂ, Identify the components of the integumentary system, Describe the layers of the skin and the functions of each layer, Identify and describe the hypodermis and deep fascia, Describe the role of keratinocytes and their life cycle, Describe the role of melanocytes in skin pigmentation. Not only is this a problem for the individuals affected, but it also has a severe impact on our healthcare system. Adipose tissue present in the hypodermis consists of fat-storing cells called adipocytes. The skin is made of multiple layers of cells and tissues, which are held to underlying structures by connective tissue (Figure 5.4). This layer is well vascularized and has a rich sensory and sympathetic nerve supply. It is exposed to air= dry membrane. Cutaneous glands - sweat and oil glands of the skin. The color of skin is influenced by a number of pigments, including melanin, carotene, and hemoglobin. Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.. Other animal coverings, such as the arthropod exoskeleton, have different developmental origin, structure and chemical composition.The adjective cutaneous means "of the skin" (from Latin cutis 'skin'). The cells (three to five layers deep) become flatter, their cell membranes thicken, and they generate large amounts of the proteins keratin, which is fibrous, and keratohyalin, which accumulates as lamellar granules within the cells (see Figure 4). Cutaneous Membrane (skin)- largest organ Epidermis Dermis Subcutaneous layer/hypodermis Accessory Structures hair, nails, and glands It's underlying dermis is mostly dense connective tissue. 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