anaphy skin 3.1

• largest organ - skin
• second largest organ - liver
• largest gland in the body - liver
• Integumentary system - Consists of the skin and accessory organs; hair, nails, and cutaneous glands
• Skin - is the most vulnerable organ - Exposed to radiation, trauma, infection, injurious chemicals
•   Dermatology - scientific study and medical treatment of the integumentary system
• Skin - a bodies largest and heaviest organ Covers 1.5 to 20 m2; composes: 15% of body weight
• o   Epidermis - stratified squamous epithelium
• o   Dermis - deeper connective tissue layer
• o   Hypodermis - connective tissue layer below dermis (not part of skin but associated with it.
• ·         Skin thickness ranges from 0.5 to 6 mm =Thick skin covers front of hands, bottoms of feet
• Sensation - Skin is an extensive sense organ - Receptors for temperature, touch, pain, and more
• o   Thermoregulation - Thermoreceptors- Vasoconstriction/vasodilation – Perspiration
• Nonverbal communication -Facial expression - Importance in social acceptance and self-image
• squamos - type of epithelium that can be karatinized
• melanocytes - gives skin color , cell that produce pigments of skin . the pigment is called melanin
• INTEGUMENTARY SYSTEM (SKIN, HAIR, NAILS)

  o   Basic Functions

  Ø  Synthesizes vitamin D

  Ø  Excretion of urea and salts

  Ø  Protects deeper tissue from:

  ·         Mechanical damage

  ·         Chemical damage

  ·         Bacteria

  ·          Ultraviolet radiation

  ·         Thermal damage

  ·          Drying out
• INTEGUMENTARY SYSTEM (SKIN, HAIR, NAILS)

  o   Basic Functions

  Ø  Synthesizes vitamin D

  Ø  Excretion of urea and salts

  Ø  Protects deeper tissue from:

  ·         Mechanical damage

  ·         Chemical damage

  ·         Bacteria

  ·          Ultraviolet radiation

  ·         Thermal damage

  ·          Drying out
• INTEGUMENTARY SYSTEM (SKIN, HAIR, NAILS)

  o   Basic Functions

  Ø  Synthesizes vitamin D

  Ø  Excretion of urea and salts

  Ø  Protects deeper tissue from:

  ·         Mechanical damage

  ·         Chemical damage

  ·         Bacteria

  ·          Ultraviolet radiation

  ·         Thermal damage

  ·          Drying out
• INTEGUMENTARY SYSTEM (SKIN, HAIR, NAILS)

  o   Basic Functions

  Ø  Synthesizes vitamin D

  Ø  Excretion of urea and salts

  Ø  Protects deeper tissue from:

  ·         Mechanical damage

  ·         Chemical damage

  ·         Bacteria

  ·          Ultraviolet radiation

  ·         Thermal damage

  ·          Drying out
• INTEGUMENTARY SYSTEM (SKIN, HAIR, NAILS)

  o   Basic Functions

  Ø  Synthesizes vitamin D

  Ø  Excretion of urea and salts

  Ø  Protects deeper tissue from:

  ·         Mechanical damage

  ·         Chemical damage

  ·         Bacteria

  ·          Ultraviolet radiation

  ·         Thermal damage

  ·          Drying out
• INTEGUMENTARY SYSTEM (SKIN, HAIR, NAILS)

  o   Basic Functions

  Ø  Synthesizes vitamin D

  Ø  Excretion of urea and salts

  Ø  Protects deeper tissue from:

  ·         Mechanical damage

  ·         Chemical damage

  ·         Bacteria

  ·          Ultraviolet radiation

  ·         Thermal damage

  ·          Drying out
• INTEGUMENTARY SYSTEM (SKIN, HAIR, NAILS)

  o   Basic Functions

  Ø  Synthesizes vitamin D

  Ø  Excretion of urea and salts

  Ø  Protects deeper tissue from:

  ·         Mechanical damage

  ·         Chemical damage

  ·         Bacteria

  ·          Ultraviolet radiation

  ·         Thermal damage

  ·          Drying out
• INTEGUMENTARY SYSTEM (SKIN, HAIR, NAILS)

  o   Basic Functions

  Ø  Synthesizes vitamin D

  Ø  Excretion of urea and salts

  Ø  Protects deeper tissue from:

  ·         Mechanical damage

  ·         Chemical damage

  ·         Bacteria

  ·          Ultraviolet radiation

  ·         Thermal damage

  ·          Drying out
• EPIDERMIS

  ·         Outer layer

  ·         Made up of squamous epithelium that can be keratinized (hard or tough)
• Melanocytes found in deepest layer

                    - gives skin its color.
• EPIDERMIS -         

  • Mostly dead cells
  • Avascular - no blood vessels.
  • Mostly keratinocyte cells. They produce keratin, which is a protein that makes the epidermis a tough layer.
  • New cells are produced constantly and pushed upward.
  • New epidermal layer every 2-4 weeks
• Stratum Basale - Deepest epidermal layer - A single layer of stem cells and keratinocytes resting on the basement
• Stem cells - divide and divide five and give rise to keratinocytes that migrate toward skin surface to replace loss cells - also contains a few melanocytes and octile cell
• Stratum spinosum - Several layers of keratinocytes joined together by desmosomes and tight junctions - Named for appearance of cell after histological preparation (spiny) - Also contains some dendritic cells 6-13 Layers of the Epidermis
• Stratum granulosum - Three to five layers of flat keratinocytes - Cells contain dark-staining keratohyalin granules
• Stratum lucidum - Thin, pale layer found only in thick skin - Keratinocytes packed with clear protein eleidin
• Stratum corneum (surface layer) - Several layers (up to 30) of dead, scaly, keratinized cells - Resists abrasion, penetration, water loss
• DERMIS

  Found under the epidermis (2nd layer)

  Made up of dense connective tissue.

  Varies in thickness

  The epidermis and dermis are connected but rubbing may cause them to separate resulting in a blister
• dermis - Structures found in the dermis include: papillary layer, sebaceous glands, sweat glands, hair, hair follicle, erector pili, blood vessels.
• PAPILLARY LAYER

  ·         Upper layer of the dermis.

  ·         Has finger like projections called dermal papillae which on the hands and feet are arranged in definite patters that form ridges.
• PAPILLARY LAYER - ·        

  • They enhance the gripping ability of the fingers and feet
  • Patterns are genetically determined & form your fingerprints.
• SEBACEOUS GLANDS

  • Also known as oil glands
  • Keep skin moist and prevents hair from becoming brittle by producing sebum
• SEBACEOUS GLANDS - Contains chemicals that kill bacteria.
When sebum blocks the glands duct, a
whitehead appears.
Acne is an infection of the sebaceous glands
• axilla - armpit