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Body Tissues rev 12-12


Body Tissues rev 12-12 Tissue: group of cells that are similar in structure and perform a common function 4 primary tissue groups Epithelial Connective – PowerPoint PPT presentation

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Title: Body Tissues rev 12-12

Body Tissues rev 12-12
  • Tissue group of cells that are similar in
    structure and perform a common function
  • 4 primary tissue groups
  • Epithelial
  • Connective
  • Muscle
  • Nervous

  • Tissues combine to form organs
  • Organs combine to form organ systems
  • Organ systems combine to form the organism

  • Epithelial Tissue
  • sheet of cells that covers a body surface or
    lines a body cavity
  • helps form boundaries between different body
  • examples skin, lining of mouth, lining of
    digestive tract, etc.
  • protects underlying tissues

  • reduces friction because it is smooth
  • lines blood vessels and helps blood flow more
  • absorbs
  • secretes

  • Forms glands
  • glands are epithelial tissues that are
    specialized to synthesize and secrete a product
  • Characteristics of Epithelial Tissue
  • 1. Cells are packed closely together
  • 2. One surface of the tissue is free while the
    other surface is attached to the underlying
    connective tissue by the basement membrane

  • 3. Epithelial tissues are typically given 2
    names--first name indicates the number of cell
    layers present
  • one layer of cells is called simple epithelium
  • typically found where absorption and filtration
    occur and a thin epithelial layer is adapted for
    diffusion across barriers
  • many layers--stratified epithelium
  • common in high-abrasion areas where protection is
    important i.e. lining of the mouth, skin surface
  • second name describes the shape of the cells

  • 4. Cells occur in 3 types
  • squamous--thin and flat cells
  • forms the thinnest possible layer for diffusion
    filtration line vessels
  • look like a pancake when viewed from the side
  • mostly found in air sacs of lungs, kidney
    glomeruli, lining of vessels

Classification of Epithelia
  • Squamous

Figure 4.1b
  • cuboidal--cube or rounded cells (about as tall as
    are wide)
  • major function is secretion but may also be
    involved in absorption
  • line the ducts of many glands
  • has round shaped nucleus which stains very darkly

Classification of Epithelia
  • Cuboidal

Figure 4.1b
  • columnar--cylindrical cells (tall and column
  • tall cell with oval shaped nucleus
  • mostly associated with absorption, secretion of
    enzymes and mucus, and movement of materials
    (ciliated cells)
  • line the stomach, small and large intestines and
    a few ducts
  • these tissues may also have microvilli, cilia, or
    goblet cells (secrete mucus to lubricate tissues
    and trap bacteria, viruses and irritating
  • line small bronchi, uterine tubes

Classification of Epithelia
  • Columnar

Figure 4.1b
Basement Membrane
  • Underneath the cells of epithelial tissue is a
    supporting non-cellular layer called the basement
    membrane and beneath that is typically a layer of
    connective tissue.
  • The basement membrane anchors the epithelial
    layer to the stronger connective tissue
  • Epithelial cells can also be attached to each
    other by different types of cell junctions made
    up of proteins Tight junctions, Adhesive
    junctions, Gap junctions

  • Tight junctions seal plasma membranes of
    adjacent cells so tightly that nothing can pass
    between the cells
  • These are very important in epithelial layers
    that must control the movement of substances into
    or out of the body?digestive tract, bladder,
    kidney tubules

  • Adhesion junctions (also called spot desmosomes)
    are looser in structure and allow for some
    movement between cells so the tissues can stretch
    and bend i.e. skin

  • Gap junctions are connecting protein channels
    that permit the movement of ions or water between
    2 adjacent cells i.e. liver, heart, some muscle

Connective Tissue
  • found everywhere in the body
  • Major functions
  • 1. Binding or connecting of body parts
  • 2. Support of organs against gravity
  • 3. Protection
  • 4. Cushioning, insulation energy storage fat
  • 5. Produces blood cells
  • 6. Transportation
  • Has comparatively few cells and a lot of matrix
    (non-living extracellular matter) which is made
    by connective tissue cells and released into the
    space between them. The strength of the
    connective tissue comes from the matrix, not from
    the living cells themselves

  • Matrix is composed of water stabilized by
    carbohydrates, glycoproteins, minerals. This
    provides mechanical and nutritional support to
    the cells. It permits free diffusion of
    nutrients and metabolites.

  • Types of Connective tissue
  • Fibrous-connects various body parts provides
    strength, support and flexibility
  • consists of several types of fibers and cells
    embedded in a gel-like ground substance (matrix)
  • Collagen fibers--provides strength and slight
  • Elasticthin and very flexible coiled elastic
    fibers made from the protein elastin can stretch
    without breaking
  • Reticularmade of thinner collagen fibers which
    interconnect with each other serves as internal
    framework for some organs fiber flexibility is
    between elastic and collagen fibers

  • The various fibers are set in a ground substance
    made of water, polysaccharides and proteins that
    range in consistency from gel to rubbery.
  • It contains many types of cells including fat
    cells, mast cells (immune cells that detect
    foreign substances in tissue spaces and initiate
    an inflammatory response), various WBC, and
    fibroblasts (the cells responsible for producing
    and secreting the proteins that compose the
    collagen, elastic and reticular fibers).

  • Fibrous connective tissues are subclassified
    according to the density and arrangement of their
  • Loose Areolar connective tissue
  • most common type
  • contains collagen fibers and elastic fibers in a
    loose irregular pattern is very flexible but
    not strong
  • usually found below the skin, between and around
    muscles, and around blood vessels, and organs.
  • Spaces between fibers are good storage areas.

  • Dense (Regular) Connective Tissue
  • fibers are densely packed and run in the same
  • is very strong when stress is in the same
    direction as the fibers run
  • has few blood vessels and takes a long time to
  • functions to bind, protect and connect
  • primarily attaches muscles to bones or to other
    muscles, bones to bones
  • usually found in tendons, ligaments and joint

  • Elastic Connective Tissue
  • Surrounds organs that have to reguarly change
    shape or size
  • Stomach, bladder, vocal cords
  • Contains a high proportion of elastic fibers
  • Reticular connective Tissue
  • Also called lymphoid tissue
  • Serves as the internal framework of soft organs
    such as the liver, lymphatic system organs
  • Is made up of thin, branched reticular fibers

  • Specialized connective tissues
  • Cartilage is the transition tissue from which
    bone develops
  • Produced by chondroblasts which become trapped
    and enclosed in areas called lacunae no blood
    vessels, high collagen fiber and water content
    (this is why it functions as a cushion)
  • Because there are no blood vessels, mature cells
    obtain nutrients by diffusion through the ground
    substance (matrix).

  • Maintains the shape of certain body parts i.e.
    tip of your nose
  • Protects and cushions joints cartilagenous disks
    cushion the vertebrae, forms the tough covering
    of bones at joints (and helps reduce friction)

  • Bone connective tissue which contains only a few
    living cells
  • inorganic matrix with calcium and phosphate salts
    for hardness
  • Blood cells are suspended in a fluid matrix
    called plasma. Considered a connective tissue
    because all blood cells derive from earlier stem
    cells located within bone.
  • Red blood cells transport oxygen and nutrients to
    body cells and carry away the waste products.
  • White blood cells function in the immune system
  • Platelets help to form blood clots following an

  • Adipose (Fat) tissue specialized for fat storage
  • has few connective tissue fibers and almost no
    ground substance primarily made up of adipocytes
    (fat cells) (large, round cells which look empty
    but really contain an oil droplet which takes up
    most of the cell and pushes the nucleus to one
  • Primary role is insulation and cushioning stores
    energy forms a protective layer around internal
  • Found below skin, around various organs, and
    around certain muscles
  • The number of adipocytes you have is partly
    determined by genetics

Other Tissue TypesMuscle Tissue Contracts for
  • Muscle tissue is made up of tightly packed cells
    called muscle fibers. The muscle fiber cytoplasm
    contains proteins which allow the cell to
  • 3 types of muscle tissue
  • Skeletal muscle moves body parts.
  • Is connected to tendons which are connected to
  • Voluntary, multinucleated

  • Cardiac muscle
  • Found only in the heart
  • Individual cells are shorter than skeletal, have
    single nucleus
  • Cells are arranged parallel to each other
  • Have intercalated disks which function as gap
    junctions for direct electrical contact with
    neighboring cells. This allows one cell to
    activate all its neighbors so the heart can
    contract in a coordinated way.
  • Involuntary muscle

  • Smooth muscle
  • Surrounds hollow organs and tubes i.e. blood
    vessels, digestive tract
  • Smaller cells than skeletal muscles have a
    single nucleus
  • Cells arranged parallel to each other
  • Have gap junctions between cells so that it works
    in a coordinated fashion
  • Involuntary muscle

Nervous Tissue Transmit Impulses
  • Nervous tissue is made up of cells which are
    specialized for generating and transmitting
    electrical impulses. It is a rapid communication
    network for the body.
  • Is located in the brain, spinal cord and nerves
  • Neuron specialized nervous system cell which
    generates and transmits impulses.
  • Structural components cell body, dendrites, axon
  • Glial (Neuroglial) cells support neuron cells
    and supplies with nutrients

  • Functions --outer covering of the body
  • protects from dehydration
  • protects from injury
  • protects against invasion by microorganisms
    (bacteria and viruses)
  • helps regulate body temperature
  • synthesizes vitamin D
  • Sensory awareness receptors for touch,
    vibration, pain and temperature provide
    information about the environment

  • Skin consists of
  • epidermis outermost layer of stratified
    squamous epithelial tissue no blood vessels
  • is made up of 5 sub-layers stratum corneum,
    stratum lucidum, stratum granulosum, stratum
    spinosum, and stratum basale layers

  • Innermost layer stratum basale undergoes almost
    continuous mitosis. Cells are pushed upward by
    the production of new cells beneath them and
    create new skin
  • Melanocytes are found here they produce melanin,
    a brown pigment.
  • Primary reason for differences in skin color is
    the activity (not number) of melanocytes. In
    darker races, melanocytes are always active in
    lighter skinned people, the melanocytes are
    activated by UV radiation.
  • Stratum spinosum thickest layer cells switch
    from a mitotic role to producing keratin.
  • Keratin is a waterproofing protein which also
    toughens the outer surface of the skin.
  • Macrophages (phagocytes which protect us from
    infection) are also present throughout this skin

  • Stratum granulosum acts as a protective shield
    to the layers below it.
  • Stratum lucidum thin layer with keratin
    production occurring
  • Stratum corneum outermost and toughest layer of
  • Outermost layers of epidermis are made up of
    dead, dried out epithelial cells which contain
    keratin (a fibrous protein, also a component of
    fingernails and hair)
  • When cells are dead and water has evaporated,
    keratin forms a tough barrier which
    microorganisms generally have a tough time
  • Provides protection from abrasion, cells can be
    rubbed off and will be replaced also protects
    our body from drying out
  • Skin continually being renewed throughout our life

  • The dermis is primarily dense connective tissue
    with collagen, elastic and reticular fibers in a
    ground matrix.
  • The fibers allow the skin to stretch when we move
  • give it strength to resist abrasion and tearing.
  • Our skin becomes less flexible and more wrinkled
    as we age because the number of fibers in the
    dermis decreases.

  • composed of two sub-layers
  • this layer binds the body together
  • richly supplied with nerve fibers, blood vessels,
    hair follicles, sebacious (oil) glands, sweat
    glands and lymphatic vessels
  • Sensory nerve endings for heat, cold, touch,
    deep pressure, vibration provide information
    about the outside environment
  • Nerve fibers
  • Meissners corpuscles-light touch
  • Pacinian corpuscles-deep pressure. Free nerve

  • There are 2 types of sweat glands
  • Eccrine which are throughout the body and
  • Apocrine which are primarily in the groin and
    underarm (axillary) areas. Because of the waste
    products of bacteria who live off of apocrine
    sweat glands, we can have an odor in these areas.
  • Sweat helps in temperature regulation and
    contains an antibiotic called dermicidin
  • Arrector pili muscles which make our hair stand
    up produce goose bumps
  • Blood vessels supply nutrients, remove waste,
    assist in temperature regulation

  • Nails a scale like modification of the epidermis
    that forms a clear protective covering on the
    dorsal surface of the ends of fingers and toes
  • Ceruminous or wax gland

  • Hypodermis supportive layer consisting of loose
    connective tissue containing fat cells
  • also called subcutaneous tissue or superficial
  • anchors the skin to underlying structures
    (primarily muscles)
  • is flexible so the skin can move and bend
  • its fat cells insulate against excessive heat
    loss and cushion against injury

Diseases of the Skin
  • Impetigo
  • A contagious, superficial infection in bullous
    (blister like) and nonbullous forms
  • Usually occurs on face, around the mouth and nose
  • ITCHY!
  • Causes
  • Staph aureus usually causative organism
  • When blister breaks, liquid (exudate) can cause
    more lesions on rest of body

  • Treatment
  • Antibiotics (penicillin, cephalosporin,
  • Anti-itch creamitching spreads impetigo
  • Frequent washing of lesions with antibacterial
  • Patient has own towels, bedding, etc
  • Caretaker must wash hands carefully and

  • Tinea (Skin Fungus) infections
  • can occur directly (through contact with infected
    lesions) or indirectly (through contact with
    contaminated articles-shoes, towels, or shower

  • Tinea capitis
  • Small, spreading blister like rash on scalp
    causing patchy hair loss and scaling
  • Usually affects children in babies called
    cradle cap
  • Tinea corporis (also known as ringworm)
  • produces flat lesions on the skin which, as they
    get bigger, have healed centers and look like a
  • Tinea pedis (Athletes foot)
  • Scaling and blisters between the toes

  • Tinea cruris (Jock itch)
  • Produces red, raised, sharply defined, itchy
    lesions in the groin that can extend to the
    buttocks, inner thighs, and the external
  • Warm weather and tight clothing encourage fungal
  • Treatment for all Tineas
  • Usually topical creams
  • Continue applying cream for 2 weeks after lesions
  • Observe for secondary infections
  • Expose areas (when possible) to air

  • Scabies
  • Infection by the itch mite which causes a
    sensitivity reaction
  • Occurs primarily in areas with overcrowding and
    poor hygiene
  • Very contagious transmitted through skin or
    sexual contact
  • Mite lives in the skin. Female burrows into the
    skin to lay her eggs. The larvae emerge to
    copulate and then reburrow under the skin

  • Causes itching which intensifies at night and can
    lead to a secondary bacterial infection
  • Lesions are usually excoriated, threadlike, about
    3/8 inch long and typically seen between fingers,
    on flexor surfaces of wrist, on elbows, underarm,
    at the waistline, and can be seen in genitalia
  • Treatment
  • Cream over entire skin surface and left on for
    8-12 hours for 5 days (depending on the specific
    type of cream)
  • Application usually repeated in 1 week
  • Oral antihistamine
  • Wash clothes and bedding in very hot water or

  • Lice or Pediculosis
  • Pediculus capitis (head lice)
  • Pediculus corporis (body lice)
  • Pediculus pubis (crab lice)
  • Lice feed on human blood and lay their eggs
    (nits) in body hairs or clothing fibers
  • After nits hatch, lice must feed within 24 hours
    or die. Mature in 2-3 weeks
  • When louse bites it injects a toxin into the skin
    that produces irritation and a purpuric spot
    (spot containing leaked blood).

  • Causes itching which can cause skin breakdown,
    swollen lymph glands, rash
  • Treatment
  • Special shampoo, creams
  • Shampoo applied and washed off after 5-10 minutes
    (depending on specific shampoo) repeat in 7-10
  • After this, all nits should be combed out of hair
    with a metal nit comb
  • Wash clothing and bedding

  • Psorias
  • Chronic disease marked by epidermal
    proliferation skin is covered by scales
  • Life cycle of normal skin is 28 days and then
    it sloughs off life cycle of psoriatic skin is 4
    days so the cell cant mature resulting in thick,
    flaky skin
  • Has remissions and exacerbations
  • Tendency to develop this is genetic
  • Symptoms itching dry, cracked skin lesions
    which can cause pain.
  • Lesions commonly appear on scalp, chest, elbows,
    knees, shins, back, and buttocks

  • Treatment
  • No permanent cure exists
  • Lotions or tar preparations to help soften the
    scales which then can be scrubbed off gently
    ultraviolet light to retard rapid cell
  • Steroid creams to control disease
  • Antihistamines to relieve itching
  • Not contagious

  • Eczema
  • Chronic inflammatory response often associated
    with allergies, irritating chemicals, temperature
    and humidity, skin irritation (i.e. tight
    clothing), and emotions.
  • Lesions generally begin as raised areas on skin
  • Typically flares and subsides repeatedly
  • During flareups, itching and scratching can
    cause edema, crusting and scaling
  • Treatment eliminate allergens and irritations
  • Antihistamines to relieve itching, steroid
    creams Hydrate skin Short baths/showers in cool