HHIS221

• Thin filament

  Contains F-actin, associated protein, troponin & tropomyosin, G-actin (binding site for myosin)
• A band

  Dark band; components are thick myosin and overlapping portion of thin and thick (reason why its dark)
• Thin filament

  I band hence lighter
• Protein involved/responsible for attachment of z-disk to thin filament

  Alpha actinin
• Types of muscle fiber

  • Type I
  • Type IIA
  • Type IIB
• Type IIB muscle fiber


  • Color pink or sometimes colorless
• Type I muscle fiber

  Slow oxidative
• Type I and IIA muscle fibers

  • High amount of myoglobin
• Layers of integumentary

  • Epidermis
  • Dermis
  • Hypodermis/Subcutaneous layer
• Epidermis

  Stratified squamous keratinized; 4 cells present are keratinocytes, langerhans, merkel, melanocytes
• Merkel cells


  Sensing gentle touch
• Melanocytes


  Pigment producing cell; pigment melanin
• Albinism


  Due to lack/defect of tyrosinase
• Vitiligo


  Decrease activity of melanocytes
• Layers of epidermis

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


  Squames (provides protection against friction and water-loss)
• Stratum lucidum

  Absent in thin skin
• Tonofibrils


  Structure present in keratinocytes in stratum spinosum; attachment of tonofibrils to desmosome
• Layers of dermis

  • Reticular
  • Papillary
• Papillary layer


  Closer to epidermis
• Hypodermis


  Mostly adipose/adipocytes/loose connective tissue; fibroadipose connective tissue
• Skin appendages

  • Hair
  • Nails
  • Skin glands
• Skin glands

  • Sebaceous
  • Sweat glands
• Sebocytes


  Cells of sebaceous glands; produce sebum
• Sweat glands

  • Eccrine
  • Apocrine
• Apocrine sweat glands


  Located at axillae (armpit) & perineum (region between thighs/groin area; male - scrotum and anus; female - opening vagina and anus) secretes substances made up of protein rich
• Eccrine sweat glands


  Located skin surface; secretes water
• Cardiovascular & lymphatic

  • Cardiovascular - blood vascular system
  • Lymphatic
• Cardiovascular - blood vascular system


  Components are heart, blood vessel, blood
• Blood vessels

  • Capillary
  • Veins
  • Artery (know the subtypes of these)