Integument

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Integument

• Biology 211Anatomy Physiology I
• Dr. Tony Serino

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Integument System Skin

• Functions
• Protection
• Germ and water proof barrier, abrasion resistant
• Sensory
• Organ in first contact with external environment
• Homeostasis
• Thermoregulation (excretory), Ca balance
• Communication
• Muscle attachment
• Secretes phermones for communicating

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Layers of the Skin

• Epidermis
• Outermost layer, composed of keratinocytes
• Dermis
• Thickest layer, composed of many connective
  tissues and is the site for many glands and other
  epidermal derivatives
• Subcutaneous layer (Hypodermis)
• Attaches skin to underlying structures

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Epidermis

• Composed of 4-5 layers of keratinocytes which is
  formed into a stratified squamous epithelium
• Main gene product is keratin, a water insoluble
  protein
• Some cells from the dermis invade and reside in
  the epidermis deepest layers including Merkel
  cells, Langerhans cells, and melanocytes

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Epidermal Layers
(basale)
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Epidermis of thin skin
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Dermis

• Composed of a mixture of CT, including dense
  irregular, loose areolar, elastic, and adipose
  tissues
• Divided into 2 regions
• Papillary layer region of dermal papillae
• Reticular layer thickest layer of skin,
  provides strength, elasticity and space for
  glands, hair follicles, etc.

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Dermal Papillae arranged into regular patterns
in palms and soles
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Papillary Region
Reticular Region
Hypodermis
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Burns
1st
2nd
3rd
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Skin Cancers
Squamous cell carcinoma
Melanoma
Basal cell carcinoma
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Epidermal Derivatives

• Structures which grow from the epidermis but
  reside mostly in the dermis
• Nails, Hair, and glands of skin

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Nail
Nail Fold
Nail Matrix
Nail Bed
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Hair
Hair shaft
Sebaceous gland
Hair root
Hair papilla
Hair Bulb
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Melanocytes produce melanin
Two types produced pheomelanin (brown-black)
and eumelanin (yellow-reddish)
Carotenoids pigments associated with fat and
subcutaneous areas
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Exocrine Glands

• Secrete product into duct or external surface
• Only single cell gland in human is the Goblet
  cell
• All other glands can be classified by structure
  or type of secretion method used

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Functional Classification method of secretion

• Merocrine secretion
• Secretes by exocytosis using vesicles
• Apocrine secretion
• Secretes by storing product in cells tip (apex),
  then breaking of entire tip
• Holocrine secretion
• The entire cell is secreted with its product

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Merocrine Secretion

• Secretes by exocytosis using vesicles

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Apocrine Secretion
Secretes by storing product in cells tip (apex),
then breaking of entire tip
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Holocrine Secretion
The entire cell is secreted with its product
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Structural Classification

• Grouped by duct structure
• Simple a single duct leads from secretory unit
  to surface
• Compound duct branches to connect surface to
  secretory unit
• Grouped by shape of secretory unit
• Tubular tube shaped
• Alveolar (Acinar) flask-like sac

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Epidermal Glands

• Sebaceous glands secretes sebum (an oil) used to
  maintain skin and hair moisture
• Ceruminous glands secretes cerumen (ear wax),
  used to keep foreign objects out of ear
• Sudoriferous (sweat) glands secrete sweat (water
  with some salts), used in heat regulation and in
  phermone secretion two types Apocrine and
  Eccrine (Merocrine)
• Mammary Glands secrete milk

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Sweat Glands
Apocrine associated with axilla and groin
functional at puberty
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Eccrine (merocrine) sweat glands most abundant
functions in thermoregulation
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Breast
(Coopers)
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Mammary gland
(Lactating)
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Breast Cancer and Mammograms
Normal
Tumor