INTEGUMENTARY

    Cards (66)

    • Epidermis
      Continuously proliferating stratified squamous epithelium which produces non-living surface layer of the protein, called keratin. Associated lipid which is indirect contact with the external environment which is constantly shed.
    • Epidermis
      • Epidermal ridges
      • Dermal papillae
      • Papillary layer - the thicker layer between epidermal ridges and dermal papillae
    • Dermis
      Fibrous and fibro-adipose tissue which supports the epidermis both physically and metabolically. This consists of several blood vessels, nerves, and sensory receptors.
    • Subcutaneous layer/Hypodermis
      Layer beneath the dermis, usually contains the adipose tissue with supporting fibrous bounds with larger vessel which supplies and drain the dermal blood and vasculature.
    • Skin
      • Largest organ in the body, both in weight and surface area showing a significant variation
      • Thickest skin found on the soles of our feet, while the thinnest area is the delicate skin on the upper and lower eyelids
      • Gives a protective factor in our body
      • External body surface and provides a protection against a wide variety of external threats including mechanical, water loss, biological and ultraviolet light
      • Most frequent mechanical insult = frictional and sheering forces experienced by the soles and ventral aspect of our toes and to a lesser extent, the palms, and the ventral aspect of our fingers
    • Microorganisms penetrating skin
      Alert resident lymphocytes and antigen presenting cells in the skin
    • Melanin
      Dark pigment that protects the epidermis ultraviolet radiations
    • Skin is the first physical defense of the body
    • Sensory receptors in skin

      • Allow skin to constantly monitor the environment
      • Skin is the largest sensory organ in the body containing a range of different receptors for touch, pressure, pain, and temperature
      • Sensory receptors are most numerous in our skin, which has the most physical contact with the environment
      • Mechanoreceptors are important for the body's interactions with physical objects
    • Pacinian corpuscles
      • Oval structures found deep in the reticular dermis and hypodermis, measuring approx.. 0.5mm by 1mm
      • Sense coarse touch, pressure and vibrations
      • Found deep in the body including wall of the rectum and urinary bladder, where they also produce sensation of pressure when the surrounding tissue is being distorted
    • Thermoregulatory functions of skin
      • Accelerates heat loss and heat conservation
      • Adjustment of blood circulation through our skin particularly in extremities, in our hands, feet. and ear. The skin provides heat conservation & heat loss
      • Sweat is produced by eccrine glands
      • Subsequent evaporation = major heat loss mechanism
      • In cold environment, the pores are constricted along with the blood vessel, so the conserve heat needed by the body
    • Vitamin D3 (Cholecalciferol)

      Synthesized by the action of ultraviolet light on the precursor 7-Dihydrocholesterol. This is further processed by liver and kidney, to produce the active agent 1.25 Dihydroxycholecalciferol. Needed in calcium metabolism and proper bone formation.
    • Dermatoglyphics
      Serve as personal identification; patterns assumed by ridges and intervening sulci that can appear as loops, whorls and arches. Very specific into a certain person.
    • Epidermis
      • Anlage: ECTODERM
      • Lining Epithelium: Stratified Squamous Keratinized Epithelium
    • Cells in epidermis
      • Keratinocytes
      • Langerhans Cells - antigen presenting cells
      • Melanocytes - pigment-producing cells
      • Merkel Cells - tactile epithelial cells
    • Melanin is derived from the amino acid tyrosine
    • Epidermis renewal
      Renewed every 15-30 days
    • Epidermal layers
      • Corneum
      • Lucidum
      • Granulosum
      • Spinosum
      • Basale
    • Stratum basale
      • Site of active mitosis
      • Also known as stratum germinativum
      • Deepest layer of epidermis
      • Columnar or cuboidal cells resting on the basement membrane at the dermal-epidermal junction
      • Contains melanocytes
    • Stratum spinosum
      • Polyhedral cells with central nucleus and cytoplasm that actively synthesizes keratin
      • Few layers of mitotically active polyhedral keratinocytes have an extension called intercellular bridges that terminates in the desmosomes
      • Cytoplasm contains a lot of keratin filaments
      • Thickest layer composed of multi-layer of cuboidal-like cells that are bought together by means of numerous desmosomal junctions and they produce keratin
    • Stratum granulosum
      • Consists of 3-5 layers of flattened polygonal cells undergoing terminal differentiation
      • Keratohyaline granules - phosphorylated proteins containing histidine and cysteine that serves as precursors of proteins
      • Lamellated granules - Ovoid or rod-like structures containing lamellar disks which are formed by lipid bilayers; Acts as barrier for the penetration of foreign materials in contact with the skin
    • Stratum lucidum
      • Consists of a thin, translucent layer extremely flattened eosinophilic cells
      • Is only seen in thick skin
      • Can only be seen in palms & soles
    • Stratum corneum
      • Consists of 15-20 layers of squamous, non-nucleated keratinized cells
      • Continuously shed cells by the process of desquamation
      • The most superficial layer consisting of: flat, unnucleated and keratinized cells filled with keratin filaments embedded in a dense matrix of protein
    • Melanocytes produce melanin
    • Albinism
      Skin hypopigmentation; a congenital disorder in tyrosine/tyrosinase (which is important in the production of melanin)
    • Vitiligo
      Involves skin de-pigmentation. Only in affected patches or due to the loss or decreased
    • S. Lucidum
      • 2-3 layers of anucleate, dead cells; seen only in thick skin
    • S. Granulosum
      • 3-5 layers of keratinocytes with distinct kerato-hyaline granules
    • S. Spinosum
      • Several layers of keratinocytes all joined by desmosomes; Langerhans cells present
    • S. Basale
      • Deepest, single layer of cuboidal to low columnar cells in contact with basement membrane; Mitosis occurs here; melanocytes and Merkel cells are also present
    • Melanocytes
      Cells that produce melanin
    • Melanin disorders
      • Albinism
      • Vitiligo
    • Degree of skin pigmentation
      Determined by the rate of melanin production, rate of transfer to keratinocytes, and melanosome degradation
    • Factors that increase melanin
      • UV Radiation
      • Estrogen
      • Melanocyte-stimulating hormone (MHS)
      • Adrenocorticotropic hormone
    • Malphigian layer
      Composed of both stratum basale and stratum spinosum
    • Eumelanin
      Brownish-black pigment produced by melanocyte
    • Pheomelanin
      Similar pigment found in red hair
    • Dendritic cells
      • Mediate contact allergic responses in skin and delayed hypersensitivity reactions; Most seen in spinous layer; Antigen-presenting cell (APC) that bind and process to antigen to T-lymphocytes; Derived from bone marrow and blood-borne cells
    • Merkel cells

      • Derived from neural crest cells; Sensory mechanoreceptor, essential for light touch sensations; Located in the basal epidermal layer
    • Dermis
      Connective tissue layer below the epidermis and its basement membrane; Supports the epidermis, binding it to the subcutaneous tissue; Has many projections that interdigitate with projections of the epidermis; Adapts with the increase body surface because it contains many elastic fibers; Contains blood vessels, blood supply and lymphatic drainage
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