chapter 6/Integumentary System

Overview of the Integumentary System

  • The integumentary system is composed of the skin and its associated structures.
  • Major components include the epidermis, dermis, subcutaneous layer, hair, nails, and various glands.

Layers of the Skin

Epidermis

  • Structure: Outermost layer, consists of stratified squamous epithelium.
  • Layers:
    • Stratum corneum (most superficial, keratinized, constantly shed)
    • Stratum basale (deepest, produces new epithelial cells)
  • Functions: Protection from wear and tear, UV protection due to melanin.

Dermis

  • Structure: Beneath the epidermis, composed of connective tissue, vascular.
  • Contains: Hair follicles, sebaceous glands, sweat glands, sensory receptors, blood vessels.
  • Functions: Nourishes epidermis, provides skin elasticity, sensory perception.

Subcutaneous Layer

  • Structure: Beneath dermis, composed mainly of loose connective tissue and adipose tissue.
  • Functions: Connects skin to underlying muscles, regulates temperature, provides insulation.

Accessory Structures

  • Sebaceous (Oil) Glands:
    • Structure: Saclike glands associated with hair follicles.
    • Function: Secrete sebum that lubricates skin and hair.
  • Sweat (Sudoriferous) Glands:
    • Structure: Coiled glands venting to skin surface.
    • Function: Release perspiration for thermoregulation and excretion of wastes.
  • Hair: Composed of keratin, grows from a follicle; functions in insulation and protection.
  • Nails: Protects distal ends of fingers and toes, assist in grasping objects.

Functions of the Integumentary System

  • Protection against infection and dehydration.
  • Regulation of body temperature (vasodilation and vasoconstriction).
  • Sensory information collection via nerve endings and receptors.
  • Minor excretion of waste products through sweat.
  • Production of vitamin D.

Observations of Skin

  • Skin color is influenced by:
    • Melanin: Brown pigment.
    • Hemoglobin: Red pigment.
    • Carotene: Yellowish-red pigment.
  • Cyanosis: Bluish discoloration due to lack of oxygen.
  • Jaundice: Yellow discoloration related to bile pigment.

Repair of the Integument

Steps in Wound Healing

  1. Inflammation: Blood brings healing cells and factors.
  2. New blood vessel growth.
  3. Fibroblasts produce new connective tissue.
  4. Epithelial cells proliferate to cover the wound.
  • Factors Affecting Healing: Nutrition, blood supply, infection, age.

Aging Effects on the Integumentary System

  • Thinning skin, formation of wrinkles, decreased pigmentation, reduced circulation.
  • Changes in hair thickness and sweat gland activity.

Disorders of the Integumentary System

  • Common Disorders:
    • Skin lesions (e.g., macules, papules, vesicles).
    • Pressure ulcers (decubitus ulcers, bedsores).
    • Burns (categorized by depth).
    • Skin cancer (basal cell, squamous cell, melanoma).
    • Infections (bacterial, viral, fungal).
    • Inflammatory conditions (dermatitis, psoriasis).
    • Accessory organ disorders (acne, alopecia).

Skin Cancer

  • Most common cancer type in the US includes basal cell carcinoma, squamous cell carcinoma, and melanoma.
  • Risk factors include sun exposure and skin type.

Inflammatory Disorders

  • Dermatitis: Inflammation characterized by redness, heat, and itching.
  • Psoriasis: Autoimmune condition characterized by rapid skin cell growth, leading to scaling and redness.

Pop Quiz & Review Points

  • Important terms related to skin disorders, repairs, and functions should be memorized.
  • Comprehension of mechanisms and changes associated with both normal and pathological states of the skin is crucial for exams.