BIOH111 SN06 Integumentary System .oIntegumentary system oSkeletal system ... BIOH111 –INTEGUMENTARY

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  • Endeavour College of Natural Health endeavour.edu.au 1

    BIOH111

    oCell Module

    oTissue Module

    o Integumentary system

    oSkeletal system

    oMuscle system

    oNervous system

    oEndocrine system

  • Endeavour College of Natural Health endeavour.edu.au 2

    Textbook and required/recommended

    readings

    o Principles of anatomy and physiology. Tortora et al; 14th

    edition: Chapter 5

  • Endeavour College of Natural Health endeavour.edu.au 3

    BIOH111 INTEGUMENTARY

    SYSTEM MODULE

    o Session 6 (Lectures 9 and 10) Structure and

    function of the skin and accessory structures

  • BIOH111Lectures 9 and 10

    Structure of the skin and accessory

    structures

    Department of Bioscience

    endeavour.edu.au

  • Endeavour College of Natural Health endeavour.edu.au 5

    Preparation for this session

    o Complete any missing concepts and linking words from

    Session 5

    o Consider epithelial membrane called cutaneous

    membrane what is it composed of and where can it be

    found?

  • Endeavour College of Natural Health endeavour.edu.au 6

    ObjectivesLecture 9:

    Structure of skin

    Define and describe the structure of each skin layer

    Accessory skin structures

    Define and describe the structure of each accessory skin structure

    Lecture 10:

    Functions of skin

    Define and describe the function the skin

    Wound healing

    Describe process of the epidermal wound healing

    Describe the process of deep wound healing

    Compare epidermal and deep wound healing

    Burns

    Describe types of burns and damages to the skin layer

    Describe method for measuring the extent of burns

  • Endeavour College of Natural Health endeavour.edu.au 7

    INTEGUMENTARY SYSTEM

    FUNCTIONS o Thermoregulation

    o Blood reservoir

    o Protection

    o Cutaneous sensations

    o Synthesis of Vitamin D

    o Excretion

  • Endeavour College of Natural Health endeavour.edu.au 8

    GENERAL ANATOMY

    www.webmd.com

    o Large organ composed of all 4 tissue

    types; 2m2 in area; 1-2 mm thick;

    weight: 4.5 kg

    o 3 layers (top 2 layers constitute

    cutaneous membrane):

    1. Epidermis: superficial portion; composed of epithelial tissue

    2. Dermis: deeper layer; primarily composed of connective tissue

    3. Hypodermis (or subcutaneous layer): deepest layer; consists of areolar and adipose tissue; not part of the skin

    http://www.webmd.com/beauty/wrinkles/cosmetic-procedures-overview-skin

  • Endeavour College of Natural Health endeavour.edu.au 9

    EPIDERMIS

    o Stratified squamous epithelium:

    avascular (contains no blood vessels)

    4 types of cells divided into 5 distinct strata (layers)

  • Endeavour College of Natural Health endeavour.edu.au 10

    SPECIALISED CELLS OF EPIDERMIS1. Keratinocytes:

    produce keratin and contain lamellar

    granules

    function: help protect the skin and

    underlying tissue from heat, microbes,

    and chemicals; release lipids (waterproof)

    2. Melanocytes:

    produce pigment melanin

    function: contribute to skin colour and

    absorb damaging ultraviolet (UV) light

    3. Langerhans cells:

    derived from bone marrow

    function: participate in immune response

    4. Merkel cells:

    contact tactile (Merkel) disc

    function: sensation of touch

  • Endeavour College of Natural Health endeavour.edu.au 11

    LAYERS (STRATA) OF THE EPIDERMIS

  • Endeavour College of Natural Health endeavour.edu.au 12

    STRATUM BASALE

    (STRATUM GERMINATIVUM)

    o Deepest single layer of epidermis

    o Cells: Merkel cells, melanocytes, keratinocytes and stem cells

    that divide repeatedly; cells attached to each other and to the

    basement membrane by desmosomes and hemi-

    desmosomes

  • Endeavour College of Natural Health endeavour.edu.au 13

    STRATUM SPINOSUM

    o Cells: mostly keratinocytes; some melanocytes; 8 to 10 cell

    layers are held together by desmosomes

    o Function: provides strength and flexibility to the skin

    o Melanin is phagocytosed by keratinocytes after nearby

    melanocytes secrete it in secretory vesicles

  • Endeavour College of Natural Health endeavour.edu.au 14

    STRATUM GRANULOSUM

    o Transition layer between the deeper, metabolically active

    strata and the dead cells of the more superficial strata

    o Cells: keratinocytes which contain lamellar granules (release

    lipid that repels water) and dark-staining keratohyalin

    granules (keratohyalin converts tonofilaments into keratin);

    3-5 layers of flat dying cells that show nuclear degeneration

  • Endeavour College of Natural Health endeavour.edu.au 15

    STRATUM LUCIDUM

    o Present only in the fingers tips, palms of the hands, and soles

    of the feet.

    o Three to five layers of clear, flat, dead keratinocytes that

    contain keratin precursor

  • Endeavour College of Natural Health endeavour.edu.au 16

    STRATUM CORNEUM

    o 25 to 30 layers of flat dead cells filled with keratin and

    surrounded by lipids from lamellar granules; continuously shed

    o Function: barrier to light, heat, water, chemicals and bacteria

    o Callus: an abnormal thickening of the epidermis with constant

    exposure to friction to this layer

  • Endeavour College of Natural Health endeavour.edu.au 17

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    o Keratinization is replacement of cell contents with the protein

    keratin; occurs as cells move to the skin surface over 2-4 weeks

    KERATINIZATION

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    https://www.studyblue.com/notes/note/n/integument-/deck/4421919

  • Endeavour College of Natural Health endeavour.edu.au 18

    DERMIS

    o Structure: connective tissue

    layer composed of collagen and

    elastic fibers, fibroblasts,

    macrophages and adipocytes

    o Contains hair follicles, glands,

    nerves and blood vessels

    o Two major regions of dermis

    1. Papillary region

    2. Reticular region

  • Endeavour College of Natural Health endeavour.edu.au 19

    1. PAPILLARY REGION

    o Top 20% of dermis; finger-like projections

    are called dermal papillae

    o Structure: areolar connective tissue

    containing fine elastic fibers, Meissners

    corpuscles, free nerve endings, adipose

    cells, hair follicles, sebaceous glands,

    sudoriferous glands

    o Functions: anchors dermis to epidermis;

    provides strength, extensibility (ability to

    stretch), and elasticity (ability to return to

    original shape after stretching)

    What is the function of

    the Meissners

    corpuscules and free

    nerve endings?

  • Endeavour College of Natural Health endeavour.edu.au 20

    2. RETICULAR REGION

    o Bottom 80% of dermis

    o Structure: dense irregular

    connective tissue that contains

    interlacing collagen and elastic

    fibers; oil glands, sweat gland

    ducts, adipose and hair follicles

    o Function: provides strength,

    extensibility and elasticity to skin

  • Endeavour College of Natural Health endeavour.edu.au 21

    SKIN COLOUR PIGMENTS

    o Melanin: complex polymer derived from

    tyrosine; produced by melanocytes in

    epidermis

    UV in sunlight increases melanin

    production

    o Carotene: yellow-orange pigment

    (precursor of vitamin A); found in

    stratum corneum and dermis

    o Haemoglobin: red, oxygen-carrying

    pigment in blood cells

    if other pigments are not present,

    epidermis is translucent so pinkness will

    be evident

  • Endeavour College of Natural Health endeavour.edu.au 22

    ACCESSORY STRUCTURES

    OF SKIN

    o Develop from the embryonic

    epidermis

    o Cells sink inward during

    development to form:

    Hair

    Oil glands

    Sweat glands

    Nails

  • Endeavour College of Natural Health endeavour.edu.au 23

    HAIR (PILI)o Present everywhere except palms,

    palmar surfaces of the digits, soles

    and plantar surfaces of the digits.

    o Structure:

    Shaft: above the skin surface

    Root: penetrates the dermis and

    subcutaneous layer

    Sebaceous apocrine gland attached

    o Function: prevents heat loss;

    decreases sunburn; eye protection

    (eyelashes); senses light touch

    (hair root plexus)

  • Endeavour College of Natural Health endeavour.edu.au 24

    GLANDS OF THE SKIN

    o Specialized exocrine glands found in dermis

    1. Sebaceous (oil) glands

    2. Sudoriferous (sweat) glands eccrine and apocrine

    3. Ceruminous (wax) glands

  • Endeavour College of Natural Health endeavour.edu.au 25

    SEBACEOUS (OIL) GLANDS

    o Sebaceous (oil) glands are usually

    connected to hair follicles; they are

    absent in the palms and soles; secretory

    portion of gland is located i