Integumentary System Quiz - Gen Ana 1

Overview of the Integumentary System

• Largest organ system of the body, providing protective barrier against external damage.
• Regulates body temperature and contributes to sensory perception.

Structures of the Integumentary System

• Skin: Composed of three primary layers: epidermis, dermis, and hypodermis.
• Hair: Provides insulation and protection.
• Nails: Protects the tips of fingers and toes.
• Glands:
  • Sweat glands: Regulate temperature.
  • Sebaceous glands: Produce oil to lubricate skin and hair.
  • Ceruminous glands: Produce earwax.
  • Mammary glands: Present in females for milk production.

Structure of the Skin

• Composed of multiple layers:
  • Epidermis: Outermost layer detecting sensations.
  • Dermis: Provides strength, flexibility, and elasticity.
  • Hypodermis: Separates the skin from underlying tissues and organs, containing fat.

Layers of the Skin

• Epidermis: Five to six layers of cells rich in nerve endings. Contains keratinocytes, melanocytes, and Langerhans cells.
• Dermis: Dense network of collagen and elastin fibers, with blood vessels, lymphatic vessels, and nerve endings. Divided into:
  • Papillary dermis: Loose connective tissue.
  • Reticular dermis: Dense connective tissue.
• Hypodermis: Fatty tissue composed of adipocytes, fibroblasts, and blood vessels.

Layers of the Epidermis

• Stratum Corneum: Layer of dead cells providing a barrier; replaced continually.
• Stratum Lucidum: Thin, clear layer not always present; found in thick skin.
• Stratum Granulosum: Contains keratin and dying cells transitioning to the outer layer.
• Stratum Spinosum: Living cells producing keratin; includes immune cells.
• Stratum Basale: Innermost layer with actively dividing cells; contains melanocytes.

Mnemonic for Epidermis Layers

• "Cats Love Gigantic Sailing Boats" helps to remember: Corneum, Lucidum, Granulosum, Spinosum, Basale.

Epidermal Lipids

• Synthesized in the epidermis, crucial for skin barrier function.
• Types include triglycerides, fatty acids, phospholipids, cholesterol, cholesterol esters, glycosphingolipids, and ceramides.

Keratinocytes

• Main cells in the epidermis, responsible for keratin production.
• Structure includes nucleated cytoplasm and specialized junctions.
• Present in all epidermal layers except stratum basale, where new cells are generated.

Keratin

• A protein providing strength and elasticity to skin, hair, and nails.
• Type I: Acidic, low molecular weight; forms heterodimers with Type II.
• Type II: Basic or neutral, higher molecular weight; contributes to stable filaments.

Thick vs. Thin Skin

• Thick Skin: Contains more layers, thicker dermis; found on palms and soles; more sebum production.
• Thin Skin: Thinner dermal layer; present everywhere else; less sebum, more prone to damage.

Locations of Main Skin Types

• Thick Skin: Palms, soles, fingertips, flexor surfaces.
• Thin Skin: Covers the remainder of the body.

Melanocytes

• Produce melanin for skin and hair pigmentation, protecting against UV radiation.
• Located in the stratum basale of the epidermis.

Melanin Types

• Eumelanin: Predominantly responsible for brown and black pigment.

Structure of Hair Follicle

• Composed of several regions:
  • Infundibulum: Extends from skin surface to follicle opening.
  • Isthmus: Middle portion connecting infundibulum to bulb.
  • Bulb: Base where hair growth occurs; contains dermal papilla and hair matrix.
  • Structures include sebaceous glands, arrector pili muscles, hair root, and shaft.

Parts of the Body Where Hair Is Present

• Hair Locations: Scalp, eyebrows, eyelashes, facial hair, body hair (chest, abdomen, back, arms, legs).
• Hairless Areas: Palms, soles, lips.

These notes provide an encapsulated view of the integumentary system, covering its components, functions, and key structural details.