BIOLOGY 2

• System consists of the skin and accessory structures, such as hair, glands, and nails.

  Integumentary system
• Functions of the Integumentary System:

  PROTECTION SENSATION TEMPERATURE REGULATION VITAMIN D PRODUCTION EXCRETION
• 2 Major parts of the skin:

  Epidermis Dermis
• Most superficial layer of the skin Consists of epithelial tissue Layer of stratified squamous epithelium

  Epidermis
• produces keratin which makes the cell hard

  Keratinocytes
• most superficial layer of epidermis

  Stratum Corneum
• Deepest layer of Epidermis

  Stratum Basale
• Layers of Epidermis

  Corneum Lucidum Granulosum Spinosum Basale
• Connective tissue with fibroblast, fat cells, macrophages

  Dermis
• Collagen & elastic fibers are responsible for most of the structural strength

  Dermis
• Layers of Dermis

  Superficial Papillary Deeper Reticular
• Also called Dermal Papillae - Which extends toward the epidermis - It also contains blood vessels, remove waste products, and aid in regulating body temperature.

  Superficial Papillary
• Main layer of the dermis - The elastin and collagen fibers are oriented more in some directions than in others and produce cleavage or tension lines in the skin

  Reticular Layer
• Produced by Melanocytes

  Melanin
• Group of pigments responsible for skin, hair, and eye color. - It provides protection against ultraviolet light from the sun.

  Melanin
• One of the most common characteristics to all mammals

  Hair
• where hair develops

  Hair Follicle
• produces the hair

  Matrix
• – contains blood vessels in hair

  Hair papilla
• it protrudes above the surface of the skin

  Shaft
• below the surface in hair


  Root
• expanded base of the hair root

  Hair bulb
• the central axis of the hair; contains soft keratin

  Medulla
• forms the bulk of the hair; hard keratin

  Cortex
• Two Major Glands of the Skin

  Sebaceous Gland Sweat Gland
• it produces sebum; It lubricates the hair and the surface of the skin to prevent drying and it protects against some bacteria.

  Sebaceous
• 2 types of sweat gland

  Merocrine and Apocrine
• they produce sweat which is a secretion of mostly water with a few salts.

  Merocrine
• responsible for body odor; influence of sex hormones

  Apocrine
• visible part of the nail

  Nail body
• whitish, crescent shaped area at the base of the nail.

  Lunula
• nail fold that extends to the nail body

  Cuticle
• part of the nail covered by the skin

  Nail root
• where nail attaches; give rise to the cells that form the nail

  Nail bed
• where nail root extends distally; give rise to the cells that form the nail

  Nail matrix
• Most common type of skin cancer - Has varied appearance: some are open sores that bleed, ooze or crust.

  Basal Cell Carcinoma
• Second most common type of skin cancer - Appear as wartlike growth - Persistent, scaly red patch

  Squamous Cell Carcinoma
• Least but most deadly type of skin cancer - Stops producing melanin - It develops in pre-existing moles

  Melanoma