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Anatomy Ch 6
Integumentary system and other crap
Question | Answer |
---|---|
Skin is also called | the cutaneous membrane |
Contains 2 layers | epithelial tissue overlying connective tissue |
Outer layer is the | epidermis |
Deeper layer is the | dermis |
Epidermis: | Outer layer; Stratified squamous epithelium; Basement membrane between epidermis and dermis |
Dermis: | Inner layer; Thicker of the 2 layers of the skin; Connective tissue; Contains collagenous and elastic fibers |
Subcutaneous layer (hypodermis): | Beneath dermis; insulating layer; Areolar and adipose connective tissue; Not considered part of the skin; Contains blood vessels that supply skin |
Epidermis characteristics | Stratified squamous epithelium; rests on basement membrane. Lacks blood vessels. Stratum basale nourished by blood vessels in dermis.As cells grow, migrate toward free surface, away from nutrient supply. Keratinocytes, begin to flatten and die. |
Keratinization: | Process of hardening, dehydration, and keratin accumulation that occurs in epidermal cells as they migrate outward. |
Keratin: | Tough, fibrous, waterproof protein made and stored in the cells |
As cells reach outer surface, become tightly packed, develop desmosomes, form outer layer, ______ | stratum corneum |
5 layers of epidermis | Stratum corneum; Stratum lucidum: Stratum granulosum. Stratum spinosum. Stratum basale/germinativum: |
Functions of epidermis: | Protects against water loss, harmful chemicals, mechanical injury, pathogens. |
Stratum corneum | Outermost layer; Many layers of keratinized, dead epithelial cells that are flattened and non-nucleated |
Stratum lucidum (only present in thick skin) | Between stratum corneum and stratum granulosum on soles and palms; Cells appear clear; nuclei, organelles, and cell membranes are no longer visible |
Stratum granulosum | Beneath the stratum granulosum; Many layers of cells with centrally located, large, oval nuclei and developing fibers of keratin; cells becoming flattened |
Stratum basale (basal cell layer) | Deepest layer; A single row of cuboidal or columnar cells that divide and grow; this layer also includes melanocytes |
Melanocytes | located in the stratum basale produce the dark pigment melanin; Absorbs UV light from sunlight and provides skin colour |
Melanin is distributed into ... | keratinocytes, to protect skin cells from damaging effects of UV light (DNA damage, fibroblast damage, skin cancer). |
Factors Affecting Skin Color: | Hereditary Factors, Environmental Factors, Physiological factors |
Dermis 2 layers: | Papillary layer, reticular layer |
Papillary layer | •Superficial layer.•Areolar connective tissue.•Thinner of the 2 layers.•Location of dermal papillae. |
Reticular layer: | •Deeper layer.•Dense irregular connective tissue.•Thicker of 2 layers. |
Accessory structures of the skin: | •Hair follicles.•Nails.•Skin glands (sweat and sebaceous). |
Nail plate | overlies nail bed. |
Nail bed: | surface of skin, under nail plate. |
Lunula | most active growing region; pale, half-moon-shaped region at base of nail plate. |
Hair follicle: | Tube-like depression of epidermal cells from which hair develops; extends into dermis or the subcutaneous layer. |
3 parts of hair: | •Hair bulb (dividing cells). •Hair root.•Hair shaft (dead, epidermal cells). |
HAIR FOLLICLE PART OF ______ , LOCATED IN _______ | EPIDERMIS; DERMIS |
Hair papulla contains.... | blood vessels to nourish hair |
Hair color is due to ... | type and amount of melanin |
Goosebumps caused by... | Arrector pili muscle |
androgenic alopecia | Most common type of baldness is pattern baldness; top of head loses hair; Associated with lowered level of testosterone (men) or estrogen (women) |
Alopecia areata | body produces antibodies that attack hair follicles; autoimmune hair loss. |
Sebaceous glands | Groups of specialized epithelial cells; Keep hair soft, pliable, waterproof; Near or connected to hair follicles, everywhere but on palms and soles |
Merocrine sweat glands | Abundant sweat glands with odorless secretion; Lower body temperature; Originate in deep dermis or subcutaneous layer and open to surface on forehead, neck, and back |
Apocrine sweat glands | Less numerous sweat glands with secretions that develop odors; Wet skin during pain, fear, emotional upset, and sexual arousal; Near hair follicles in armpit and groin |
Ceruminous glands | Modified sweat glands; Secrete ear wax; External acoustic meatus |
Mammary glands | Modified sweat glands; Secrete milk; Breasts |
Skin is versatile, and vital for... | homeostasis |
Functions of the skin | •Protective covering, barrier against harmful substances and microorganisms.•Prevents some water loss.•Contains sensory receptors.•Excretes some wastes.•Helps produce Vitamin D.•Helps regulate body temperature. |
Set point of body temperature is monitored by ______ | Hypothalamus |
Deep body temperature stays close to set point of .... | 37 degrees Celsius or 98.6 degrees Fahrenheit |
____is a product of cellular metabolism. | Heat |
most active body cells are major heat producers: | skeletal muscle, cardiac muscle, cells of the liver. |
When body is too warm, body responds with ... | vasodilation of dermal blood vessels and vasoconstriction of deep blood vessels. |
Methods of heat loss: | Radiation;Conduction;Convection;Evaporation |
Radiation | Primary method, infrared heat rays escape. |
Conduction | Heat moves from skin to cooler objects |
Convection | Heat loss into circulating air currents |
Evaporation | Sweat changes into a gas, carries heat away. |
Hyperthermia | abnormally high body temperature |
Hyperthermia details: | Can occur on hot, humid day, when sweat cannot evaporate.•When air temperature is high, radiation is less effective.•Body may gain heat from hotter air.•Skin becomes dry, person gets weak, dizzy, nauseous, with headache, rapid pulse. |
Hypothermia | abnormally low body temperature |
Hypothermia details: | Can result from prolonged exposure to cold, or illness.•Shivering is involuntary skeletal muscle contraction, caused by hypothalamus.•Progresses to confusion, lethargy, loss of reflexes and consciousness.•Without treatment, organs shut down. |
Inflammation | normal response to injury or stress. Inflammation is body’s attempt to restrict spread of infection. Blood vessels in affected tissues dilate and become more permeable, allowing fluids to leak into the damaged tissues |
Inflamed skin may become: | •Reddened.•Swollen. •Warm.•Painful. |
shallow cut: | affects only the epidermis, results in epidermal cells along its margin dividing more rapidly than usual, to fill gap |
deep cut: | reaching dermis or subcutaneous layer, results in blood vessels breaking; released blood forms a clot |
Clot consists of... | fibrin, blood cells and platelets |
Clot and dried tissue fluid form... | scab |
Wound healing process: | Epithelial cells reproduce, fill in the wound.•Fibroblasts secrete collagen fibers to bind wound together.•Growth factors stimulate new tissue formation.•Phagocytic cells remove dead cells and debris, scab sloughs off. |
Scar | Excess collagenous fibers form elevated mass |
Superficial, partial-thickness (first degree) burn: | •Injures only epidermis, as in sunburn; redness, heat, inflammation.•Healing takes days-weeks, no scarring. |
Deep, partial-thickness (second degree) burn: | •Destroys epidermis and some dermis, as in burn from hot liquid. •May blister, healing varies with severity of burn & stem cell survival.•Stem cells in hair follicles and glands can help regenerate skin.•Usually recovers completely, no scarring. |
Full-thickness (third degree) burn: | •Destroys epidermis, dermis, accessory structures.•Results from prolonged exposure to heat, flames, hot liquids.•Some healing from margins.•Often requires skin graft, skin substitutes. |
Rule of Nines | divides body surface into regions of 9% or multiples of 9 for burn treatment |
Anterior Trunk burn | 18% |
Posterior Trunk burn | 18% |
Anterior AND posterior head&neck | 9% |
Perineum burn | 1% |
Anterior (front) of lower extremities (legs) | 18% |
Posterior (back) of lower extremities (legs) | 18% |
Anterior (front) of upper extremities (arms) | 18% |
Posterior (back) of upper extremities (arms) | 18% |