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Chapter 5
Question | Answer |
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________ - Skin and its accessory organs. EX: hair, nails, glands, muscles and nerves | Integument |
_________ - The study of the skin. Medical specialty dealing with diagnosis and treatment of skin disorders | Dermatology |
The Integument consists of 2 distinct layers: | Sepidermis - superficial layer composed of epithelium Dermis - Deeper layer composed of connective tissue. ALSO: Hypodermis (Subcutaneous) - not technically part of the skin. SubQ layer deep to skin composed mostly of adipose tissue |
4 Types of cells found in the epidermis | Keratinocytes, Melanocytes, Langerhans cells, Merkel cells (discs) |
4-5 Layers from supericial to deep in the epidermis | Stratum corneum Stratum lucidum (only visible in thick skin) Stratum granulosum Stratum Spinosum Stratum Basale |
Epidermal Cells: Most abundant cell type (90%) Produce lamellar granules: make skin "water proof", and go continuous mitosis | Keratinocytes. Produce Keratin: fibrous protein that helps give the epidermis it's protective properites. |
Epidermal Cells: Produce melanin, have long arm-like processes that project into neighboring keratinocytes. | Melanocytes. 1 melanocyte can contact ~30 keratinocytes which are given melanin. Melanin is used to protect the cell's DNA from UV light and gives skin color. Melanin granules cluster to form veils over the nucleus. but the Mealanocytes can't protect self |
Epidermal Cells: Macrophages that help activate the immune system. Produced in red bone marrow and migrate to the epidermis | Langerhans' Cells: produced in red bone marrow and migrate to the epidermis. Have liong arm like processes and surround themselves around keratinocytes. Roam around the epidermis looking for and phagocytizing foreign substances. |
Epidermal Cells: Least numerous of the epidermal cells, present at the epidermal/dermal junction. Functions as a sensory receptor for light touch. | Merkel (tactile) cells: least numerous of the epidermal cells. Present at the epidermal/dermal junction. Associated witha disk-light sensory nerve ending - merkel disk. Functions as a sensory receptor for light touch. |
Deepest layer of the epidermis: Single row of cuboidal keratinocytes: some of which are stem cells | Stratum Basale. (Basal layer = basement) Deepest layer of the epidermis, youngest mitotically dividing keratinocytes. Keratinocytes contain tonofilaments composed of the proteins that will eventually form keratin. Contains numerous melanocytes merkel cell |
Prickly Layer: cells appear to have spines | Stratum Spinosum: cells appear to have spines. 8-10 cell layers thick of mostly keratinocytes directly superficial to the stratum basale. Abundant melanin granules. Abundant Langerhan's cells. Occasional Merkel's cells. |
3-5 cell layers of flattened dying keratinocytes ~ in the middle of the epidermis superficial to stratum spinosum. Too far away from nutrients so cells begin apoptosis. | Stratum Granulosum. Keratinization begins. Tonofilaments become converted to keratin via the protein keratohyalin. Accumulate lammellated granules. Lipids secretion that fills the space between cells in the stratums granulosum lucidum and corneum |
Keratinization begins when tonofilaments become converted to keratin via the protein _______. | Keratohyalin |
Thin translucent band between stratum granulosum and stratum corneum | Stratum Lucidum: 2-3 rows of clar flattened dead keratinocytes. Visible ONLY in thick skin (fingertips, palms of hands, soles of feet) |
20-30 cell layers thick of dead, thin, flat, plasma membrane enclosed packages of keratin. Keratinocytes are now called corneocytes. 3/4 of epidermal thickness. | Stratum Corneum: most superficial layer, cells slough off. Provides a durable overcout for the body. Keratin - protects against abrason and penetration. Water proof - protects from water loss. Average person sheds 40 lbs of skin "flakes" in a lifetime. |
_______ - strong, flexible connective tissue located directly underneath the epidermis. Highly supplied with vessels (blood and lymph) and nerve fibers. | Dermis |
Hair follicles, sweat glands, sebaceous glands, sensory receptors all may be derived from ______ but reside in the ______. | Epidermal tissue; dermis |
Two distinct layers of the dermis | Papillary layer, reticular layer. |
Thin superficial layer of the Dermis is the _________. Contain _______ which are indentations of the papillary layer that project into the epidermis, allowing for a greater surface area between the dermis and epidermis. | Papillary layer; dermal papillae. The papillary layer also contains capillaries, free nerve endings for pain and temperature as well as Meissner's corpuscles for touch receptors. |
Epidermal/ Dermal ridges on palms of hands and soles of feet form ________. | Friction ridges. Epidermal ridges lie atop dermal ridges (papillae) which increases friction to enhance grip. Ridge patterns are genetically determined and unique to individuals. This forms finger prints. |
deeper layer of the dermis making up 80%. made of Dense Irregular Connective Tissue. | Reticular layer. The reticular layer also contains Cutaneous plexus (blood vessels) sweat and sebaceous glands, hair follicles, pacinian corpuscles (for pressure and vibration) and arrector pilli muscle (raises hair). |
_______ of dermis has Lots of collagen and elastic fibers provide the skin with extensibility and elasticity. If stretched too much stretch marks will occur. | Reticular layer |
Collagen forms in bundles to create ________. | Cleavage lines. Most of the collagen fibers run in parallel (logitudinally) to the skin. when incisions are made parallel to these lines, wounds heal more rapidly and scaring is less. |
Three pigments contribute to skin color. | Melanin- the only one made in the skin, carotene, hemoglobin. |
______ range of pigment color from yellow to tan to reddish-brown to black. | Melanin. The kind and amount of melanin produced varies buta ll people have the same number of melanocytes |
Two different types of Melanin | Eumelanin: brownish - black pigment Pheomelanin: yellow - red pigment |
Melanin is produced in the _______ and migrates to ______. | Produced in the melanocytes and migrates to keratinocytes. |
Melanin is produced in the ________ of the melanocyte using tyrosine and the enzyme ______. | Produced in the melanosomes of the melanocyte using tyrosine and the enzyme tryosinase. |
Local accumulation of melanin can cause _____ or ________. | Freckles or moles. |
Melanocytes are stimulated to make more melanin when skin is exposed to sun. This leads to _______ | Tan. |
_______- inherited condition where a person can not produce melanin. | Albinism - cannot synthesize tyrosinase |
_______- condition where there is loss of melanocytes from a portion of the skin resulting in white patches. May be autoimmune | Vitiligo |
______ - a yellow to orange pigment found in plant products ( ex shrimp and carrots) Accumulates in _____ and ______ | Carotene is the yellow to orange pigment found in plant products and accumulates in fatty tissues and the stratum corneum (the most outer layer). |
Large amounts of carotene can be converted to _______ | Vitamin A. Vitamin A is essential for vision and epidermal health |
________- Reddish/pink pigment found in oxygenated blood. | Hemoglobin |
________- Blue appearance; indicates poorly oxygenated blood | Cyanosis |
______-Red appearance; can indicate fever, hypertension, inflammation, allergy and embarassment | Erythema |
______- White (Pale) appearance; can indicate anemia, low blood pressure, fear, anger and emotional stress. | Pallor |
______ - Yellow appearance; can indicate a liver disorder | Jaundice |
_______- Brozing: increased / darker pigmentation; can indicate Addison's disease (hypoadrenalism) | Bronzing |
Black-blue bruises; indicates that blood has escaped capillaries and pooled in a certain spot | Hematomas |
_______ - release their secretion by exocytosis either through a pore or though a hair follicle. 2 types | Sweat glands. Eccrine glands and Apocrine glands |
_______ sweat glands. Very numerous, abundant on palms, soles and forehead. The secretory unit lies in teh dermis. Duct extends through the epidermis opening through a pore onto the skin. Functions in thermoregulation | Eccrine sweat glands. Sweat - 99% water/salts/Urea,uric acid/glucose, lactic acid/metabolic wastes. |
______ sweat glands. ~2000 glands in the entire body, largely confined to the axillary and anogenital areas. Secretory portion located in the dermis or hypodermis, duct dumps into a hair follicle. Begin functioning at puberty | Apocrine sweat glands. Sweat: components of eccrine sweat + fatty substances, proteins, and is a viscous/milky yellow color. Odor forms after it is broken down by microbes. Begins at puberty. |
_______ glands - modified apocrine glands that line the external ear canal. Secretion mixes with sebum to form cerumen (earwax). | Ceruminous glands |
________ glands - secrete oil. found all over the body except in thick skin of the palms and soles. Most develop from hair follicles or occasionally from a pore. Become more active during puberty. | Sebaceous glands. Oil softens and lubricates hair and skin, slows water loss from the skin, and is bactericidal. |
Structure of hair: ______ projects from the skin | Shaft |
_____ of hair extends the shaft into the dermis | Root |
______ of hair is the middle layer containing elongated cells with pigment (unless it is gray or white hair, then they are just filled with air) | Cortex |
______ of hair - outer layer with thin flattened keratinized cells | Cuticle |
______ Epithelium that separates the external root sheath from the cuticle. | Internal root sheath |
_______ - continuation of the stratum basale of epidermis | External root sheath |
______ - onion shaped structure at the base of the follice. contains the papilla of the hair - arolar connective tissue with blood vessels. Matrix - cells fromt eh bstatum basale to replenish old hair | Bulb |
______ soft, fine hair of children and adult females | Vellus hair |
______ long, course hair. scalp, eyebrows, axillary region, facial and chest hair. Grow in response to androgens (male sex steroids/testosterone) | Terminal hair |
_________ - stratum corneum extended over nail body | Eponychium (cuticle) |
_____ - epithelium deep to nail root with mitotically active cells | Nail matrix |
_____________ most common (78%) and least malignant form of skin cancer | Basal cell carcinoma, cancer in the stratum Basale layer of the epidermis which will invade the dermis and hypodermis. cured by surgical removal in 99% of cases |
_________ second most common (20%) form of skin cancer. | Squamous Cell carcinoma. Arises from keratinocytes in teh stratum spinosum. Grows rapidly and can metastasize if not removed surgically in the early stages. |
______ most dagnerous form of skin cancer. | Melanoma. Cancer of the malanocytes. ABCD rule is used to recognize melanoma. A-asymmetry B- border irregularity C- color D- diameter |