Week+2+Chapter+12+-+Updated+2023

Chapter 12: Skin - Integumentary System

Overview

  • This chapter discusses the integumentary system, focusing primarily on the skin and its functions, structures, related glands, disorders, and treatments.

Vocabulary Related to the Integumentary System

Word Parts
  • Definitions and anatomical terms relevant to understanding the integumentary system concepts.
Medical Terms
  • Various medical terms relevant to the integumentary system are introduced and defined.

Functions of the Integumentary System

  • The integumentary system comprises the skin and its related structures, playing vital roles in body health.
      - The term integument comes from Latin, meaning "to cover" or "enclose."
Functions of Skin
  • Forms protective outer layer for the body.
      - Waterproofing: Prevents fluid loss.
      - Immune System Role: Intact skin blocks pathogens.
      - Sensory Reception: Major receptor for touch.
      - Vitamin D Synthesis: Converts UV light to vitamin D, filters harmful UV radiation.
      - The skin is the largest bodily organ, covering approximately 2 square yards in adults.
Related Structures of the Integumentary System
  • Includes sebaceous glands, sweat glands, hair, and nails.
      - Sebaceous Glands: Secrete sebum (oil) for skin lubrication and antibacterial properties.
      - Sweat Glands: Regulate temperature and water, excreting metabolic waste.
      - Hair: Controls body heat loss.
      - Nails: Protect the dorsal surfaces of fingers and toes.

Structures of the Skin

  • The skin is composed of three basic layers:
      1. Epidermis
      2. Dermis
      3. Subcutaneous Layer
  • Cutaneous: Pertaining to the skin.
The Epidermis
  • The outermost layer, composed of specialized epithelial tissues.
      - Lacks blood vessels and connective tissue, dependent on lower layers for nourishment.
      - Consists mainly of squamous epithelial tissue, noted for flat, scaly, continuously shedding cells.
      - The basal layer generates new cells that migrate upwards and become keratinized.
Keratin
  • A fibrous protein in the epidermis.
      - Soft Keratin: Primary component of the epidermis.
      - Hard Keratin: Found in hair and nails.
  • Melanocytes: Cells in the basal layer producing melanin, the pigment responsible for skin color, protecting against UV damage.
The Dermis
  • Also known as corium, it is a thick layer beneath the epidermis containing connective tissue, blood vessels, and nerve fibers.
      - Houses hair follicles, sebaceous glands, and sweat glands.
      - Contains sensory nerve endings for touch, temperature, pain, and pressure.
Tissues Within the Dermis
  • Collagen: Fibrous protein providing strength and flexibility.
  • Mast Cells: Respond to injury and allergies by releasing heparin (anticoagulant) and histamine (causes allergic responses).
The Subcutaneous Layer
  • Connects skin to underlying muscles, consists of loose connective and adipose tissue.
      - Lipocytes: Fat cells predominant in this layer, storing fat.
      - Cellulite: Ordinary fatty tissue described as dimpled fat deposits.
The Sebaceous Glands
  • Located in the dermis and associated with hair follicles, secrete sebum for lubrication and antibacterial properties.
The Sweat Glands
  • Tiny, coiled glands on nearly all body surfaces divided into:
      - Apocrine Glands: Located at hair follicles.
      - Eccrine Glands: Open directly onto the skin, more numerous in palms and soles.
Perspiration
  • Composed of 99% water, salts, and metabolic waste, perspires to cool the body and excrete