Integumentary System and Skin

Introduction

• Skin is the body's largest organ and part of the integumentary system.
• Functions as a barrier, aids in homeostasis, sensory functions, and Vitamin D production.

Functions of Skin

• Maintains internal body temperature and fluid balance.
• Protects internal organs from damage and pathogen invasion.
• Contains sensory receptors for touch.

Skin Structure

• Composed of layers: epidermis, dermis, and hypodermis.

Epidermis

• Outermost layer; contains keratinocytes that produce keratin.
• Stratum Corneum: Top layer, consists of dead, cornified cells.
• Stratum Lucidum: Found in thick skin (e.g., palms, soles), transparent appearance.
• Stratum Granulosum: Contains keratinocytes that flatten and lose organelles.
• Stratum Spinosum: Contains layers of keratinocytes and cells acting like macrophages.
• Stratum Basale: Deepest layer, site of basal cells undergoing mitosis.
  • Contains melanocytes (produce melanin) and Merkel cells (touch sense).

Dermis

• Contains blood vessels, sweat glands, hair follicles, nerves.
• Composed of collagen and elastin fibers for support and elasticity.
• Papillary Layer: Loose connective tissue.
• Reticular Layer: Dense connective tissue.

Hypodermis

• Connects skin to bones and muscles.
• Contains adipose tissue for insulation.

Accessory Structures

• Sweat Glands: Aid in temperature regulation via sweat.
• Sebaceous Glands: Produce oil, waterproof skin and hair.
• Hair: Growth occurs in dermis; shaft made of keratin.
• Nails: Composed of dead keratinocytes; growth from nail root.

Skin Conditions

Skin Cancer

• Basal Cell Carcinoma: Arises from basal cells.
• Melanoma: Arises from melanocytes.
• Merkel Cell Carcinoma: Rare, aggressive.

Burns

• Categorized by depth:
  • First Degree: Affects epidermis.
  • Second Degree: Affects epidermis and part of dermis.
  • Third Degree: Affects epidermis and dermis.
  • Fourth Degree: Extends to bones and muscles.
• Severe burns compromise skin functions and increase infection risk.

Conclusion

• Understanding the integumentary system aids in treating skin conditions and injuries.

Remember: Stay curious and continue exploring the functions and importance of the integumentary system.