1. What is the Integumentary system and its primary characteristics?
Integumentary system is the skin and its derivatives; it provides external protection for the body. Its characteristics are: Covers the entire body, Accounts for about 7% of total body weight, Pliable, yet durable, Thickness: 1.5 to 4.0 mm, Composed of the epidermis and dermis,
2. Describe and give at least one example of each of the functions of the Integumentary system.
A. Protection – 3 different barriers: Chemical Barriers (skin secretion and melanin) Physical/Mechanical Barriers – continuity of the skin and hardness of keratinized cells Biological Barriers – Langerhans’ cells, macrophages, and DNA
B. Body temperature- Production of copious amounts of sweat to dissipate heat; Constriction of dermal blood vessels to retain heat
C. Cutaneous Sensation- cutaneous sensory receptors (nervous system)
D. Metabolic Functions - Synthesis of Vitamin D – increases calcium absorption in the body; Chemical conversion of many substances
E. Blood Reservoir- vasoconstriction and vasodilation
F. Excretion- elimination of nitrogen-containing wastes, salt, and water
3. Differentiate between chemical, physical/mechanical and biological barriers provided by the Integumentary system. Be sure to provide a minimum of one example for each.
Chemical Barriers (skin secretion and melanin) Physical/Mechanical Barriers – continuity of the skin and hardness of keratinized cells Biological Barriers – Langerhans’ cells, macrophages, and DNA
4. Create a chart that helps you differentiate the epidermis and dermis. Be sure to include things such as cell composition, cell populations and layers.
|Epidermis |Dermis | |Composed of epithelial tissue |Composed of fibrous connective tissue | |Cell population= keratinocytes(majority) which produce keratin. |Cell population=fibroblasts producing a semi-fluid matrix | |Melanocytes which synthesize melanin (deepest layer of the epidermis) |Macrophages | |Langerhans cells (macrophagues), arise from the bone marrow. Merkel |Mast cells and which blood cells | |cells which are sensory receptors that are located at the epidermal. |Subdivided into two layers Papillary layer(thin) and the Reticular | | |layer | |LAYERS |Major portions of the hair follicles and oil and sweat glands are in | |Stratum basale, deepest layer attached to the dermis. |this layer. | |Stratum granulosum three to five layers thick. | | |Stratum lucidum, thick skin only, found on palms and feet soles and | | |fingertips. Has flat dead keratinocytes. | | |Stratum corneum, outermost layer, 20 to 30 cell layers thick. | | | | |
5. Order the layers of the epidermis from outermost to deepest.
Stratum corneum, stratum lacidum, stratum granulosum, stratum spinosum, stratum basale.