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Integumentary
The Integumentary System
Question | Answer |
---|---|
What is the hypodermis? | The subcutaneous tissue just deep to the skin. It is also called the superficial fascia because it is superficial to the tough connective tissue wrapping of the skeletal muscles. |
What does the hypodermis do? | Stores fat. anchors the skin to the underlying structures (mostly to muscles). acts as a shock absorber. insulates heat. |
What is the epidermis? | the outermost protective shield of the body. it is keratinizes stratified squamous epithelium. has 4 cell types and 5 layers. |
What are keratinocytes? | most epidermal cells are keratinocytes. produce keratin. |
What is keratin? | the fibrous protein that helps give the epidermis its protective properties. |
What is a callus? | persistent friction that causes a thickening of the epidermis. |
What are melanocytes? | the spider-shaped epithelial cells that synthesize the pigment melanin. |
What is melanin? | the melanin granules accumulate on the superficial or "sunny" side of the keratinocyte nucleus, forming a pigment shield that protects the nucleus from the damaging effects of UV radiation in sunlight. |
What is the function of epidermal dendritic cells? | the ingest foreign substances and are key activators of our immune system. their slender processes extend among the surrounding keratinocytes, forming a more or less continuous network. |
What is thermoregulation? | the homeostatic regulation of body temperature |
What are the two major components of the integumentary system? | skin (cutaneous membrane) and its accessory structures located primarily in the dermis (hair and nails) and various glands,muscles and nerves. |
What are some functions of the integumentary system? | -guards the physical & biochemical integrity of the body. -maintain a constant temperature. -provide sensory info about the surrounding environment. -metabolism. |
What is thermoregulation? | the homeostatic regulation of body temperature. |
What is the largest organ of the body? | the skin. it is made up of different tissues joined to perform specific functions. |
What are langerhans cells? | epidermal dendritic cells. -arise from red bone marrow and migrate to the epidermis. -participate in immune responses against microbes that invade the skin. |
What are tactile (merkel) cells? | They are located in the deepest layer of the epidermis. -they contact the flattened process of a sensory neuron. |
What is the stratum germinativum(basale)? | deepest layer of epidermis.-forms the epidermal ridges which extend into the dermis and are adjacent to the dermal papillae which extend into the epidermis. |
What cells make up the stratum germinativum? | single row of cubodial or columnar keratinocytes. they are the youngest keratinocytes. nuclei are large in this layer. melanocytes and tactile cells are also found here. |
What is the stratum spinosum? | 2nd deepest layer. The prickly layer. 8 to 10 layers of polyhedral keratinocytes bound together by desmosomes. |
What cells are found in the stratum spinosum? | cells in the more superficial portions of this layer become flattened as they produce more and more keratin filaments. |
What is the stratum granulosum? | middle layer. the granular layer. 3 to 5 layers of flattened keratinocytes that are undergoing apoptosis. the nuclei of these celss begin to degenerate and eventually die. |
What are keratohyalin granules? | found in the stratum granulosum. they help form keratin in the upper layers. and help with dehydration of cells. |
What are lamellar granules? | membrane enclosed granules found in the stratum granulosum. they release a lipid rich secretion that fills the spaces between cells of this layer and between more supeficial cells of the epidermis. |
What do the lipid rich secretions of lamellar granules do? | it is a water repellent sealant that retards loss of body fluids and entry of foreign materials. |
What is the stratum lucidum? | the 2 layer closest to the outside of the body. the clear layer. present only in skin of fingertips, palms and soles. (thick skin) 3 to 5 layers. |
What cells are in the stratum lucidum? | 3 to 5 layers of clear, flat, keratinocytes without a nucleus or organelles filled with eleidin(an intermediate in the synthesis of keratin). |
What is the stratum corneum? | 25 to 30 layers of dead, flatted keratinocytes. the horny layer. these cells are continuously shed and replaced by cells from deeper stratum. water resistant but not waterproof. |
What is the stratum spinosum? | 2nd deepest layer. The prickly layer. 8 to 10 layers of polyhedral keratinocytes bound together by desmosomes. |
What cells are found in the stratum spinosum? | cells in the more superficial portions of this layer become flattened as they produce more and more keratin filaments. |
What is the stratum granulosum? | middle layer. the granular layer. 3 to 5 layers of flattened keratinocytes that are undergoing apoptosis. the nuclei of these celss begin to degenerate and eventually die. |
What are keratohyalin granules? | found in the stratum granulosum. they help form keratin in the upper layers. and help with dehydration of cells. |
What are lamellar granules? | membrane enclosed granules found in the stratum granulosum. they release a lipid rich secretion that fills the spaces between cells of this layer and between more supeficial cells of the epidermis. |
What do the lipid rich secretions of lamellar granules do? | it is a water repellent sealant that retards loss of body fluids and entry of foreign materials. |
What is the stratum lucidum? | the 2 layer closest to the outside of the body. the clear layer. present only in skin of fingertips, palms and soles. (thick skin) 3 to 5 layers. |
What cells are in the stratum lucidum? | 3 to 5 layers of clear, flat, keratinocytes without a nucleus or organelles filled with eleidin(an intermediate in the synthesis of keratin). |
What is the stratum corneum? | 25 to 30 layers of dead, flatted keratinocytes. the horny layer. these cells are continuously shed and replaced by cells from deeper stratum. water resistant but not waterproof. |
What is the calcitriol? | the active form of vitamin D which is required for normal absorption of calcium and phosphorus by the small intestine. |
What is the dermis? | deeper, thicker layer made-up of connective tissue containing collagen and elastic fibers. |
What cells are present in the dermis? | fibroblasts, macrophages, adipocytes. |
What is the papillary layer? | first layer of the dermis. consists of areolar CT containing fine elastic fibers. |