Anatomy and Physiology: Integumentary System - The Skin

Overview

• Presented by Sarah from RegisteredNurseRN.com
• Focus on the integumentary system (skin system)
• Covers:
  • Functions of the skin layers
  • Functions of skin appendages and sensory organs
  • Includes a quiz with additional questions on her website

Functions of the Skin

• Body Temperature Regulation: Helps control our body temperature.
• Protection:
  • Protects against UV radiation and environmental hazards.
  • Sensory protection from harm (e.g., pulling away from heat).

Layers of the Skin

1. Epidermis: Superficial layer
   • Composed of keratinized stratified squamous epithelium.
   • Contains four cell types:
     • Keratinocytes
     • Melanocytes
     • Merkel cells
     • Langerhans cells
2. Dermis: Below the epidermis
   • Strong, flexible connective tissue with nerves, nerve fibers, and blood vessels.
   • Includes:
     • Dermal Papillae: Superficial layer (20% of dermis)
     • Reticular Layer: Deeper layer (80% of dermis), network of collagen fibers.
3. Hypodermis: Not part of the integumentary system
   • Acts as an insulator with a fatty layer.

Appendages of the Skin

• Types:
  • Hair follicles
  • Sebaceous glands
  • Sweat glands
  • Nails
• Hair Functions:
  • Sensing light touch and insulating the body.
  • Eyelashes and nose hairs protect against particles.

Hair and Associated Structures

• Hair Follicle: Extends from epidermis into the dermis.
• Root Plexus:
  • Sensory nerve endings around the hair bulb.
  • Sense movement of hair.
• Arrector Pili Muscle:
  • Smooth muscle that causes goosebumps.
  • Key for test: Erects skin/hair.

Glands

• Sebaceous (Oil) Glands:
  • Produce sebum.
  • Found everywhere except palms and soles.
• Sweat (Sudoriferous) Glands:
  • Produce sweat; pores open to the skin surface.
  • Not found on nipples or parts of external genitalia.
  • Types:
    • Eccrine Glands: Numerous, duct runs to skin surface.
    • Apocrine Glands: Found in axillary, anal, and genital areas, producing sweat with fatty substances and proteins.

Sensory Nerve Endings

• Meissner's Corpuscles: Sensitive to light touch, located superficially.
• Pacinian Corpuscles: Sense pain and pressure.

Quiz Summary

• Number of Skin Layers: Two (Epidermis and Dermis)
• Common Error: Including hypodermis as a layer (it's not part of the integumentary system)
• Reminder to take the full quiz on RegisteredNurseRN.com

Conclusion

• Encouraged to check more AMP lectures and quizzes
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