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45 Cards in this Set
- Front
- Back
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organ
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Two or more tissues grouped together and performing specialized functio
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. The largest organ(s) in the body is (are) the
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skin
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integumentary system
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The skin and its various structures make
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Skin and Its Tissues (functions)
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Composed of several tissue types
Maintains homeostasis Protective covering Retards water loss Regulates body temperature Houses sensory receptors Contains immune system cells Synthesizes chemicals Excretes small amounts of wastes |
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Skin Cells
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Help produce Vitamin D needed for normal bone and tooth development
Some cells (keratinocytes) produce substances that stimulate development of some white blood cells |
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Layers of Skin
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Epidermis
Dermis Subcutaneous layer A.k.a hypodermis Beneath dermis |
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Epidermis 6 characteristics
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Lacks blood vessels
Keratinized Thickest on palms and soles (0.8-1.4mm) Melanocytes provide melanin Rests on basement membrane Stratified squamous epithelia |
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There are five (5) layers of the epidermis
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Stratum corneum
Stratum lucidum (only in thick skin – palms, soles) Stratum granulosum Stratum spinosum Stratum basale |
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Explain what happens to epidermal cells as they undergo keratinization
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As new cells in the epidermis are produced, they are pushed upwards from the basement membrane towards the outside of the skin. As they get further from their nutrient source they die. As the process occurs, the maturing cells undergo a hardening process (keratinization) during which the cytoplasm develops strands of tough, fibrous, waterproof proteins called keratin. These dead cells form many tough, waterproof layers. These dead cells are rubbed away as newer cells replace them.
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Stratum coronea where and what
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Outermost layer
many layers of keratinized, dead epithelial cells that are flattened and nonnucleated |
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stratum lucidum where and what
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Between the statum corneum and stratum granulosum on soles and palms
cells appear clear;nuclei,organelles and membranes are no longer visible |
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Startum granulosum beneath stratum corneum
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three to five layers of flattened granular cells that contain shrunken fibers of keratin and shriveled nuclei
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Statum spinosum
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beneath the stratum granulosum many layers of cells with centrally located large oval nuclei and developing fibers of keratin: cells becoming flattened.
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Startum basal deepest layer
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single row of cubudiol or columnar cells that divide and grow this layer includes melanocytes.
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Epidermis Genetic Factors
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Varying amounts of melanin
Varying size of melanin granules Albinos lack melanin |
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malanocytes
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specialized cells that produce dark pigment which provides skin color.
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Physiological Factors
epidermis |
Dilation of dermal blood vessels
Constriction of dermal blood vessels Accumulation of carotene Jaundice |
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Environmental Factors
epidermis |
Sunlight
UV light from sunlamps X-rays Darkens melanin |
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Dermis characteristics (10)
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On average 1.0-2.0mm thick
Contains dermal papillae Binds epidermis to underlying tissues Irregular dense connective tissue Muscle cells Nerve cell processes Specialized sensory receptors Blood vessels Hair follicles Glands |
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Describe three physiological factors that affect skin color
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The dermal blood supply affects skin color. For example, when the blood is well oxygenated, the hemoglobin makes the skin appear pinkish. When the blood is not well oxygenated, the hemoglobin is darker and the skin appears bluish (cyanosis). In the presence of high levels of carotene in the blood, the skin may exhibit a yellowish cast. Illnesses may also affect skin color.
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Papillary layer (dermis)
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Thin
Superficial Dermal papillae here |
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Reticular layer
(dermis) |
80% of dermis
Cleavage, tension or Langer’s lines are here |
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Subcutaneous Layer
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A.k.a hypodermis
Loose connective tissue and Adipose tissue Insulates Major blood vessels present |
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Accessory Structures of the Skin
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Accessory structures of the skin originate from the epidermis and include:
Hair follicles Nails Skin glands |
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Hair Follicles
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Epidermal cells
Tube-like depression Extends into dermis Three (3) parts: Hair root Hair shaft Hair papilla |
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. Distinguish between a hair and a hair follicle
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Hair is present on all skin surfaces except the palms, soles, lips, nipples, and various parts of the external reproductive organs. A hair follicle is a group of epidermal cells at the base of a tube-like depression. The root of the hair occupies this follicle. As these cells divide and grow, they are pushed toward the surface and undergo keratinization and subsequent cell death. The cells’ remains form the structure of a developing hair whose shaft extends away from the skin surface. This shaft is called the hair.
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Review how hair color is determined
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Genes that direct the type and amount of pigment produced by epidermal melanocytes determine hair color.
Bright red hair contains an iron pigment (trichosiderin) that does not occur in hair of any other color. Gray hair is the result of a mixture of pigmented and unpigmented hair. |
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What kind melanin produce brown/black hair and what kind of melanin produce blonde hair.
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eumelanin-black
phenomelanin-blonde |
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Nails
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contain a lunula, nail bed , and plate
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Sebaceous Glands
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Usually associated with hair follicles
Holocrine glands Secrete sebum (oil) Absent on palms and soles |
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. Explain the function of sebaceous glands
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Sebaceous glands contain groups of specialized epithelial cells and are usually associated with hair follicles. They are holocrine glands that secrete an oily substance called sebum (a mixture of fatty materials and cellular debris) that serve to keep the hair and skin soft, pliable, and relatively waterproof.
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eccrine sweat glands
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abundant sweat glands that are odorless that lower body temprature
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apocrine sweatglands
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less numerous that eccorine that devlop orders, used wet skin during pain,fear,emotional upset and sexual arrousal
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ceruminous glands
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secrete earwax
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mamary glands
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secret milk in the breast.
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Regulation of Body Temperature why is it important
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Regulation of body temperature is vitally important because even slight shifts can disrupt metabolic reactions.
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The primary means of heat loss is
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radiation
Also there is conduction, convection and evaporation |
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Problems in Temperature Regulation
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Hyperthermia – abnormally high body temperature
Hypothermia – abnormally low body temperature |
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Healing of Wounds and Burns
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Inflammation is a normal response to injury or stress.
Blood vessels in affected tissues dilate and become more permeable, allowing fluids to leak into the damaged tissues. Inflammed skin may become: Reddened Swollen Warm Painful |
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First degree burn
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First degree burn – superficial, partial-thickness (dermis superficial)
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Second degree burn
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Second degree burn – deep, partial-thickness detroys epidermis and some dermis
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Third degree burn
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full thickness destroys epidermis, dermis and the accessory structures of the skin
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Autograft
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replacement from another part of ones own skin
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Homograft
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replacement from another persons skins
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. Discuss three effects of aging on skin.
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Aging skin affects appearance as “age spots” or “liver spots” appear and grow, along with wrinkling and sagging. Due to changes in the number of sweat glands and shrinking capillary beds in the skin, elderly people are less able to tolerate the cold and cannot regulate heat. Older skin has a diminished ability to activate vitamin D necessary for skeletal health.
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