ANSWER THE ESSAYS AND THE QUESTIONS

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Tissue Growth and Repair

Body Defenses at Tissue Level

  • Physical Barriers
  • Skin
  • Mucous membranes
  • Cilia
  • Stomach acid

Tissue Injury

  • Stimulates inflammatory and immune response
  • Healing process begins

Tissue Injury

  • Specific
  • Attack against invaders (bacteria, toxins, viruses)
  • Nonspecific body response
  • Prevent further injury

Inflammation

Immune Response

Tissue Repair

  • Regeneration
  • Fibrosis

Tissue Repair

  • Repair by dense connective tissue
  • Formation scar tissue
  • Replacement of destroyed tissue
  • Same kind of cells

Regeneration

Fibrosis

Regeneration or Fibrosis?

  • Depends on
  • Type of tissue damaged
  • Severity of injury
  • Clean cuts heal faster than ragged tears

After Tissue Injury

  • capillaries become permeable
  • Granulation tissue forms
  • Surface epithelium regenerates

Permeable Capillaries

  • Allows clotting proteins to reach injured area
  • Clot stops blood loss
  • Walls off injured area
  • Prevents bacteria from spreading to other tissues
  • Clot exposed to air forms scab

Granulation Tissue Formation (Underneath the scab)

  • Delicate pink tissue
  • New capillaries
  • Fragile and bleed freely
  • Phagocytes
  • Dispose of clot of fibroblasts

Surface Epithelium Regeneration

  • Across granulation tissue
  • Beneath scab
  • Cover underlying fibrous tissue (scar tissue)
  • Scar invisible or visible

Regeneration Time

  • Epithelial tissues (heal very quickly)
  • Skin
  • Mucous membranes
  • Fibrous connective tissues
  • Bone
  • Skeletal muscle

Fairly Successful

Poor

Replaced by Scar Tissue

Homeostatic Imbalance

  • Scar tissue
  • Strong
  • Lacks flexibility of normal tissues
  • Cannot perform normal function of tissue it replaces
  • Hinders organ function

Tissue Growth

Aging

  • Due to
  • Chemical insults

Drugs

CO

  • Physical factors

Radiation

  • Aging “clock”

Built into genes

Aging and Tissue Changes

  • Epithelia
  • Become thinner
  • More easily damaged
  • Skin looses elasticity and sags
  • Exocrine glands less active
  • Endocrine glands less hormones

Aging and Tissue Changes

  • Connective Tissue
  • Bones become porous and weaken
  • Tissue repair slows
  • Muscle Tissue
  • Atrophy
  • Nervous Tissue
  • Atrophy

Other Tissue Changes

  • Neoplasm
  • Uncontrolled cell division
  • Benign or malignant
  • Hyperplasia
  • Increase in cell numbers
  • Enlargement of tissue
  • Due to irritant or stimulant
  • Atrophy
  • Decrease in size
  • Loss normal stimulation