Skin - The Jack of All Trades
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Questions and Answers

Which of the following is NOT one of the three issues mentioned?

  • Bacterial infection
  • Mechanical damage
  • Nutrient deficiency (correct)
  • Loss of water by evaporation

    • Loss of water by evaporation is considered a mechanical issue.

    False (B)

    Name one method through which bacterial infection can occur.

    Contamination

    Mechanical damage, bacterial infection, and _____ are identified issues.

    <p>loss of water by evaporation</p> Signup and view all the answers

    Match the following conditions to their descriptions:

    <p>Mechanical damage = Physical harm to the structure Bacterial infection = Invasion and reproduction of bacteria Loss of water by evaporation = Reduction of moisture through vaporization</p> Signup and view all the answers

    What is a common consequence of mechanical damage?

    <p>Reduced functionality (B)</p> Signup and view all the answers

    Evaporation contributes positively to the conditions discussed.

    <p>False (B)</p> Signup and view all the answers

    Which of the following is NOT a function of the human skin?

    <p>Storage of glycogen (D)</p> Signup and view all the answers

    The malpighian layer is the outermost layer of the epidermis.

    <p>False (B)</p> Signup and view all the answers

    What is the primary pigment responsible for the color of human skin?

    <p>melanin</p> Signup and view all the answers

    The granular layer consists of ________ of flattened cells.

    <p>two or three sub-layers</p> Signup and view all the answers

    Match the skin layers to their characteristics:

    <p>Cornified layer = Outermost layer, protects against environmental hazards Granular layer = Contains flattened cells, involved in moisture retention Malpighian layer = Innermost layer, responsible for cell division Dermis = Contains elastic fibers, blood vessels, and nerves</p> Signup and view all the answers

    Which of the following activities does the skin NOT perform?

    <p>Digestion (A)</p> Signup and view all the answers

    African negroes have genetically dark-colored skin due to higher amounts of melanin.

    <p>True (A)</p> Signup and view all the answers

    List two functions of the skin.

    <p>Protection and temperature regulation</p> Signup and view all the answers

    The ________ layer presses outward to replace the worn-out cells of the outermost cornified layer.

    <p>malpighian</p> Signup and view all the answers

    The dermis does NOT contain which of the following?

    <p>Melanin (B)</p> Signup and view all the answers

    Which of the following is NOT a channel through which heat is lost from the body?

    <p>Hair (B)</p> Signup and view all the answers

    The human body temperature is typically highest in the early morning.

    <p>False (B)</p> Signup and view all the answers

    What is the principal heat-regulating centre of the body?

    <p>Hypothalamus</p> Signup and view all the answers

    Heat is lost when cold food, water, or cold beverages are taken into the body. This loss occurs through the _______.

    <p>Foods</p> Signup and view all the answers

    Match the method of heat loss with its description:

    <p>Skin = Loss through convection, conduction, radiation, and sweat Lungs = Heat loss via warm air exhaled Urine and Faeces = Heat lost through elimination at body temperature Foods = Heat loss when cold items are ingested</p> Signup and view all the answers

    What structure does a hair contain that provides it with a blood supply?

    <p>Hair papilla (C)</p> Signup and view all the answers

    A nail has five parts.

    <p>False (B)</p> Signup and view all the answers

    Name one part of the hair that has a blood supply.

    <p>Hair papilla</p> Signup and view all the answers

    A nail consists of the nail plate, nail bed, and the __________.

    <p>nail matrix</p> Signup and view all the answers

    Match the following parts of hair and nails with their descriptions:

    <p>Hair Papilla = Contains a blood supply Nail Matrix = Area where nail growth occurs Sebaceous Gland = Secretes oil to keep hair moisturized Nail Plate = Visible part of the nail</p> Signup and view all the answers

    Which part of the hair helps in its growth?

    <p>Hair papilla (C)</p> Signup and view all the answers

    The sebaceous gland is involved in the formation of nails.

    <p>False (B)</p> Signup and view all the answers

    What is the visible part of the nail called?

    <p>Nail plate</p> Signup and view all the answers

    Hair is formed within a __________ found under the skin.

    <p>follicle</p> Signup and view all the answers

    Which of the following is NOT a part of the hair structure?

    <p>Nail bed (B)</p> Signup and view all the answers

    Match the following structures with their functions:

    <p>Hair Follicle = Anchors the hair Nail Bed = Supports the nail plate Sebaceous Glands = Produces oil Hair Shaft = Visible part of hair</p> Signup and view all the answers

    What is the primary function of the erector muscle of the hair?

    <p>To pull hair upright (A)</p> Signup and view all the answers

    The skin becomes extra oily in cold and dry weather due to increased sebum secretion.

    <p>False (B)</p> Signup and view all the answers

    What are the three common problems related to sebaceous glands?

    <p>Pimples, acne, blackheads</p> Signup and view all the answers

    In hot and humid weather, the skin becomes extra oily due to an increased secretion of __________.

    <p>sebum</p> Signup and view all the answers

    Match the condition with its description:

    <p>Pimples = Result from sebum accumulation leading to bacterial infection Acne = Inflammation of sebaceous glands, common in adolescents Black heads = Clogged pores turning black upon oxidation</p> Signup and view all the answers

    How long does the duration of scalp hair growth typically last?

    <p>2-5 years (A)</p> Signup and view all the answers

    Hairs in human being do not play a role in forensic investigations.

    <p>False (B)</p> Signup and view all the answers

    What helps prevent foreign particles from entering the eyes?

    <p>Eyelashes</p> Signup and view all the answers

    Patients with inflamed sebaceous glands commonly experience __________.

    <p>acne</p> Signup and view all the answers

    What happens to an open pore when it is clogged with dead skin cells and sebum?

    <p>It turns black and is called a black head (D)</p> Signup and view all the answers

    Study Notes

    Skin - "The Jack of All Trades"

    • Skin is more than just a covering; it's a complex organ with numerous vital functions
    • It's the largest organ in the body, comprising approximately 15% of an adult's total body weight
    • Skin acts as a barrier, protecting underlying tissues from mechanical damage, fluid loss, disease-causing germs, and harmful UV light
    • Skin is a sensory organ, detecting touch, pain, pressure, heat, etc.
    • It regulates body temperature, releasing heat in warm weather and retaining it in cold
    • Stores reserve food in fat cells
    • Participates in excretion (primarily by sweating)

    What is Skin?

    • The outermost layer of the body's covering
    • Extensive network of structures and glands originate from it

    Functions of the Skin

    • Protection: Primary function, offering protection against four threats:
      • Mechanical shocks
      • Excessive water loss
      • Harmful substances and diseases
      • Excess UV light
    • Sensation: Detects various sensations like touch, pain, heat, and pressure
    • Temperature Regulation: Maintains internal body temperature by releasing or retaining heat
    • Storage: Fat cells in the skin store reserve food
    • Excretion: Supports the excretion process by eliminating water, salts, and a small amount of urea through sweating
    • Vitamin D Synthesis: Minor function, synthesizing vitamin D when exposed to sunlight.

    Structure of the Skin

    • Two main layers: Epidermis (outer) and Dermis (inner)
      • Epidermis: Stratified epithelium, layered structure, with specialized regions: cornified, granular, malpighian layers
        • The cornified layer consists of a tough protein called keratin protecting from various factors
        • Stratum malpighi, the innermost layer, contains melanin, the pigment offering coloration (e.g., complexion)
      • Dermis: Inner layer, comprises collagen fibres, elastic fibers, blood vessels, nerve endings, hair follicles, sweat glands
      • Derivatives: Structures originating from the epidermis and dermis, including hair, nails, sweat glands, and sebaceous glands

    Skin Coloration

    • Due to melanin, a pigment located in the melanocytes of the malpighian layer
    • Differences in melanin content lead to varying skin colors among humans

    Skin Derivatives

    • Hair: Provides insulation and protection from environmental extremes
    • Nails: Provide protection for the tips of the fingers and toes
    • Sebaceous Glands: Secrete sebum, an oily substance that keeps skin supple and waterproof, preventing moisture loss
    • Mammary Glands: Specialized sweat glands that produce milk
    • Sweat Glands: Responsible for cooling the body by eliminating water and salts through perspiration (sweat)

    Skin and Other Functions

    • Helps in the sense of touch
    • Involved in regulating body temperature
    • Plays a role in excreting substances (sweat)
    • Skin is a major organ protecting from harmful environmental elements

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