skin ,hair, nails

• Skin and its Layers

  • Epidermis
  • Dermis
  • Subcutaneous Layer (Hypodermis)
• Epidermis


  • Stratum corneum
  • Stratum lucidum
  • Stratum granulosum
  • Stratum germinativum (basal cell layer)
• Stratum germinativum (basal cell layer)


  • Mitosis occurs here
  • Contains melanocytes, producing melanin
• Stratum corneum


  • As cells rise, they die and their cytoplasm is converted to keratin, which has a rough, horny texture
  • This layer undergoes constant shedding
• Dermis


  • Mostly connective tissue, primarily collagen
  • Provides support and nourishment of epidermis
  • Blood vessels, nerves, muscle, sweat glands, sebaceous glands, hair follicles
• Sebaceous glands


  • Produce sebum through hair follicles, which make skin oily. Prevent water loss.
• Sweat glands


  • Eccrine – smaller, coiled tubules which open to skin surface and located over the entire skin.
  • Apocrine – larger, open to hair follicles. Located mainly in axillae, areolae of the breasts and genital area which are relatively small and nonfunctional until puberty. Produce thick secretions, which react with bacteria on skin surface to produce body odor
• Subcutaneous Layer (Hypodermis)


  • Consists mostly of fat
  • Provides protection, insulation, and caloric source
• Hair


  • Composed of keratin
  • Can be fine (vellus hair) or darker and thicker (terminal hair)
• Nails


  • Composed of keratin
  • Clear with highly vascular bed of epithelial cells underneath
• Infants


  • Lanugo – fine soft hair present at birth
  • Skin is thinner, less fat – more prone to dehydration and hypothermia
• Pregnancy


  • Linea nigra – line down midline of abdomen
  • Chloasma – face of pregnancy
  • Striae gravidarum – stretch marks

  
• Aging


  • Stratum corneum thins, loss of collagen, elastin, and fat, decrease of sebaceous and sweat glands
  • More prone to dehydration and hypothermia
• History


  • History of skin disease
  • Significant familial predispositions – allergies, hay fever, psoriasis, eczema, acne
  • Change in pigmentation
  • Change in a mole
  • Pruritus
  • Rash or lesion
  • Medications
  • Hair loss or growth
  • Change in nails
  • Exposure to hazards
  • Self care
• Physical Examination - Color

  • General pigmentation – should be even throughout
  • Benign pigmented areas
  • Vitiligo – absence of melanin in patchy areas
• Changes in Color in Light Skinned People

  • Pallor
  • Erythema
  • Cyanosis
  • Jaundice
  • Temperature
  • Moisture
  • Mobility and Turgor
  • Lesions