Integumentary System

• What are the components of the Integumentary System?

  Skin, Hair, Nails, Glands and Specialised receptor.
• What are the layers of the skin?

  Epidermis:

  • Stratum corneum
  • Stratum lucidum
  • Stratum granulosum
  • Stratum spinosum
  • Stratum basale

  Dermis
• Function of the epidermis

  Maintains body temp, protection, perception of stimuli, synthesis of vitamin D, immunity
• Function of the dermis


  Excretion
• Components of Hair


  Medulla

  • Composed of rows of polyhedral cells
  • Elladin - precursor to keratin

  Cortex - "core"

  • Forms major part of shaft
  • Elongated cells containing pigment granules

  Cuticle

  • Outer most layer
  • Single layer of thin flat scale-like cells
  • Heavily keratinised (protection)
• Components of Glands


  • Sebaceous or oil glands
  • Sudoriferous Glands
  • Ceruminous Glands
• Sebaceous or oil glands


  • Not associated with hair follicles
  • Open directly onto the surface of the skin
  • Located on lips and eyelids
  • Secrete an oily substance - sebum (fats, cholesterol, proteins and inorganic salts)
• Sudoriferous Glands


  • Derived into 2 principle types on the basis of structure and location
  • Apocrine sweat glands are simple, branched tubular glands
  • Apocrine sweat glands are located primarily in the skin of the axilla, pubic region and pigmented areas (areolae) of the breasts
  • The secretory portion of apocrine sweat glands is located in the dermis or subcutaneous layer and the excretory duct opens into hair follicles
  • Eccrine sweat glands are much more common and are simple, coiled tubular glands
• Ceruminous Glands


  • Modified sudoriferous glands
  • Present in the external auditory meatus
• Components of the Nail

  • Nail body - the portion of the nail that is visible
  • The free edge is the part that projects beyond the distal end of the digit
  • Nail root is the portion that is hidden in the proximal nail groove
• What is BCC?


  Basal Cell Carcinoma.

  • Most common
  • Rarely metastasised
  • Common in fare skin and prone to freckles
• What is SCC?


  Squamous Cell Carcinoma

  • Caused by UV, chemical carcinogens, etc
  • Most common on fair skin, light hair, prone to freckles.
  • Flaky compared to BCC
• What is Malignant Melanoma?


  Most common site of involvement is skin.

  • Can be eye, oral or Nasal mucosa

  Can be epithoidal or spindle.
• Dense Connective Tissue


  Large no. of thicker and dense fibres.

  Less cells
• Loose Connective Tissue 


  loosely wound fibres throughout tissue
• Examples of Loose CT

  Areolar Connective Tissue

  Adipose tissue

  Reticular Connective Tissue
• Areolar CT cells


  Fibroblasts, Plasma Cells, Macrophages

  • subcutaneous skin
• Adipose Tissue Cells


  Adipocytes (fat)
• Reticular CT Cells- Lymph node


  Reticular fibres, Reticular cells
• Examples of Dense CT

  Dense Regular (skeletal muscle), Dense Irregular (skin), Elastic CT (aorta)
• Cells in Dense Regular CT

  Collagen fibres & Fibroblasts
• Cells in Dense Irregular CT

  Collagen - irregularly arranged
• Cells in Elastic CT

  Elastic fibers and Fibroblasts
• Smooth Muscle

  • found in walls of hollow internal structures
  • non-striated and usually involuntary
  • provides motion (peristalsis, blood vessels)
• Cardiac Muscle

  • Forms most of heart wall
  • Striated and usually involuntary
  • Attached and communicate via desmosomes (intercalated discs)
• Skeletal Muscle

  • Attached to bones
  • Dark banding (striations) with voluntary action