Where is cutaneous membrane found

Protection The skin protects us in a variety of ways:. Mechanical - The skin physically protects the tissues that it covers. Chemical - The skin offers some protection against chemical damage. Invasion of disease agents - The skin presents a barrier against invasion by a variety of pathogens.

Ultraviolet radiation - YouTube video: Tanning is out, You Skin is in The skin protects against the damaging effects of ultraviolet radiation.

Xeroderma pigmentosum demonstrates the destructive energy of uv radiation. Thermal damage - The skin provides protection against the extremes of temperature. Desiccation - The skin provides waterproofing that protects against excessive water loss. Thermoregulation The skin contributes to our ability to maintain a constant internal body temperature by mechanisms that retain heat in cold environments and lose heat in hot environments.

Excretion The skin aids in the secretion urea and uric acid in sweat. Synthesis of Vitamin D Exposure to sunlight enables the skin to participate in the conversion of cholesterol into vitamin D.

Sensation The skin contains a variety of sensory receptors that provide information about touch, heat, cold and tissue damage. Structure of skin The bulk of the skin consists of two types of tissue: epidermis, the epithelium on the surface; and dermis, the underlying connective tissue. Subcutaneous tissue a. We will consider it with the skin. Epidermis Thick skin The epidermis is an epithelium classified as stratified squamous. It is unique in that the cells that form this epithelium, called keratinocytes, programmed to die as they are pushed to the surface.

This happens because the cells produce an intermediate filament, called keratin, that fills the cell and with other molecules gives the epidermis its properties of durability and water proofing. The stages of this process, called keratinization, that takes place over time is reflected in the different appearance of the strata layers that form this epithelium.

The epidermis can be divided into four strata:. Stratum basale The stratum basale a. These cells are the closest to the nutrients provided by the underlying connective tissue and are constantly dividing to replace the cells that are lost on the surface. Stratum spinosum The stratum spinosum is immediately superficial to the stratum germinativum. These cells are still alive and are in the process of developing stronger connections to one another. These harmful effects include burns in the short term and cancer in the long run.

The deepest layer of the skin is called the subcutaneous layer, the subcutis, or the hypodermis. Like the dermis, the layer contains blood vessels and nerves for much the same reasons.

Importantly, the subcutis contains a layer of fat. This layer of fat works alongside the blood vessels to maintain an appropriate body temperature. The layer of fat here acts as a cushion against physical trauma to internal organs, muscles, and bones. Additionally, the body will turn to this fat in times of starvation to provide power to its various processes, especially brain function.

Layers of cutaneous membranes skin : This image details features of the epidermal and dermal layers of the skin. The epidermis includes five main layers: the stratum corneum, stratum lucidium, stratum granulosum, stratum spinosum, and stratum germinativum.

The epidermis is the outermost layer of our skin. It is the layer we see with our eyes. It contains no blood supply of its own—which is why you can shave your skin and not cause any bleeding despite losing many cells in the process. The epidermis is itself divided into at least four separate parts. A fifth part is present in some areas of our body. In order from the deepest layer of the epidermis to the most superficial, these layers strata are the:. Skin overview : Skin layers, of both hairy and hairless skin.

Human skin: This image details the parts of the integumentary system. The stratum basale, also called the stratum germinativum, is the basal base layer of the epidermis. This layer is one of the most important layers of our skin. This is because it contains the only cells of the epidermis that can divide via the process of mitosis, which means that skin cells germinate here, hence the word germinativum.

In this layer, the most numerous cells of the epidermis, called keratinocytes, arise thanks to mitosis. Keratinocytes produce the most important protein of the epidermis. This protein is appropriately called keratin. Keratin makes our skin tough and provides us with much-needed protection from microorganisms, physical harm, and chemical irritation. Millions of these new cells arise in the stratum basale on a daily basis. The newly produced cells push older cells into the upper layers of the epidermis with time.

As these older cells move up toward the surface, they change their shape, nuclear, and chemical composition. These changes are, in part, what give the strata their unique characteristics. The stratum basale is primarily made up of basal keratinocyte cells, which can be considered the stem cells of the epidermis.

They divide to form the keratinocytes of the stratum spinosum, which migrate superficially. From the stratum basale, the keratinocytes move into the stratum spinosum, a layer so called because its cells are spiny-shaped cells. From there the keratinocytes move into the next layer, called the stratum granulosum.

This layer gets its name from the fact that the cells located here contain many granules. The keratinocytes produce a lot of keratin in this layer—they become filled with keratin. This process is known as keratinization. The Dermis Underneath the epidermis lies the dermis. The dermis contains: Blood vessels that nourish the skin with oxygen and nutrients. The blood vessels also allow immune system cells to come to the skin to fight an infection. These vessels also help carry away waste products.

Nerves that help us relay signals coming from the skin. These signals include touch, temperature, pressure, pain, and itching. Various glands. Hair follicles. Collagen, a protein that is responsible for giving skin strength and a bit of elasticity. The Subcutaneous Tissue The deepest layer of the skin is called the subcutaneous layer, the subcutis, or the hypodermis. They surround the cavity of joints, filling the space with the synovial fluid that they make.

The synovial fluid lubricates the ends of the bones allowing them to move freely. Many features only work on your mobile device. If you like what you see, we hope you will consider buying.