A&P exam 2 (chapter 5)

Describe the major events involved in inflammation and repair of the skin

1) homeostasis, 2) inflammatory, 3) proliferative, and 4) remodeling. An initial response to maintain homoeostasis. An inflammatory response to prevent infection. A proliferative phase to reconstitute the wound site. A remodelling phase where tissue strength and function are restored.

Identify the components of the integumentary system

Cutaneous membrane and Accessory structures. The integumentary system is an organ system consisting of the skin, hair, nails, and exocrine glands. The skin is only a few millimeters thick yet is by far the largest organ in the body.

Chapter 5: Describe the two basic layers of the skin

Epidermis; the outermost layer, which provides a waterproof barrier and gives the skin tone. Dermis; layer beneath the epidermis, contains the tough connective tissue, hair follicles and sweat glands.

Describe the components of the hydodermis layer

It consists of mostly adipose tissue and is the storage site of most body fat. It serves to fasten the skin to the underlying surface, provides thermal insulation, and absorbs shocks from impacts to the skin.

List the function of the epidermis

It provides a barrier to infection from environmental pathogens[2] and regulates the amount of water released from the body into the atmosphere through transepidermal water loss (TEWL). Barrier, Skin hydration, and skin color.

Describe the role of keratinocytes

Keratinocyte. A keratinocyte is the predominant cell type in the epidermis, the outermost layer of the skin, constituting 90% of the cells found there. Those keratinocytes found in the basal layer (stratum basale) of the skin are sometimes referred to as "basal cells" or "basal keratinocytes".

List each type of cell found in the epidermis

Keratinocytes melanocytes langerhans merkel

What are the functions of the cells of the epidermis

Keratinocytes; an epidermal cell that produces keratin. 90% of the predominant cell type in the epidermis and they form of a barrier against environmental damage by pathogenic bacteria, fungi, parasites, and viruses, heat, UV radiation and water loss. Melanocytes; are melanin-producing cells located in the bottom layer (the stratum basale) of the skin's epidermis. Melanin is the pigment primarily responsible for skin color. Langerhans; cells are dendritic cells (antigen-presenting immune cells) of the skin and mucosa, and contain large organelles called Birbeck granules. They are present in all layers of the epidermis except the stratum corneum, which protects against infections, and are most prominent in the stratum spinosum. Merkel; oval receptor cells found in the skin of vertebrates that have synaptic contacts with somatosensory afferents. They are associated with the sense of light touch discrimination of shapes and textures. They can turn malignant and form the skin tumor known as Merkel cell carcinoma.

Identify each layer of the epidermis (superficial to deepest)

Stratum Corneum Stratum Lucidum Stratum Granulosum Stratum Spinosum Stratum Basale

Describe each layer of the epidermis in detail

Stratum Corneum; This layer is composed of 15-20 layers of flattened cells with no nuclei and cell organelles. The stratum corneum is composed of three lipid components: ceramides, cholesterol, and fatty acids. The purpose of the stratum corneum is to form a barrier to protect underlying tissue from infection, dehydration, chemicals and mechanical stress. Stratum Lucidum; is a thin, clear layer of dead skin cells (composed of three to five layers of dead, flattened keratinocytes) named for its translucent appearance under a microscope. It is readily visible by light microscopy only in areas of thick skin, which are found on the palms of the hands and the soles of the feet. Stratum Granulosum; Keratinocytes migrating from the underlying stratum spinosum become known as granular cells in this layer. Stratum Spinosum; found between the stratum granulosum and stratum basal. This layer is composed of polyhedral keratinocytes. Stratum Basale; (sometimes referred to as stratum germinativum) is the deepest layer of the five epidermis layers. The stratum basale is a continuous layer of cells.

Describe the blood supply of the dermis; cutaneous and papillary plexi

The blood vessels that supply the capillaries of the papillary region are seen running through the reticular layer. The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. ... It is composed of dense, irregular connective tissue.

Describe UV light in the production of Vitamin D

Vitamin D is made when UV (more precisely, UVB rays) react with a compound (7-dehydrocholesterol) in the skin. The best rays for UV synthesis have wavelengths between 270-300 nm. These wavelengths are present when the UV index is greater than 3.