The Integumentary System (part 1)

Introduction to Integumentary System

• Course: Human Anatomy and Physiology 1 (HEAL505)

• Presented by: Stephen Brown

• Welcoming Note: Mōrena, ki a koutou katoa. (Welcome)

Overview of Skin Structure

• Skin consists of the cutaneous membrane, which includes:

  • Epidermis: Outer layer

  • Dermis: Beneath the Epidermis

  • Subcutaneous Hypodermis: Beneath the Dermis

Epidermis

• Comprises 5 layers or "strata" and is made of epithelial tissue.

• Avascular: Lacks blood supply.

• Contains mainly keratinocytes that produce keratin.

• Epidermis layers renewed every 25-40 days.

Layers of the Epidermis

• Stratum Corneum:

  • Most superficial layer (75% of epidermal thickness).

  • Made of keratinized dead cells, providing protection.

  • Surface cells flake off.

• Stratum Basale:

  • Deepest layer, where constant cell reproduction (mitosis) occurs.

  • Contains melanocytes (produce melanin) and receives nourishment from the dermis.

Cell Types in the Epidermis

• Keratinocyte:

  • Most abundant, produces tough keratin protein.

• Melanocyte:

  • Produces melanin for UV protection.

• Tactile Epithelial Cell:

  • Signals sensory neurons in the dermis.

• Intradermal Macrophage:

  • Phagocytic cell that destroys pathogens.

Dermis

• Located beneath the epidermis; varies in thickness (thicker on palms and soles).

• Composed of two layers:

  • Papillary Layer (20% of dermis)

    • Contains dermal papillae, contributing to fingerprints.

  • Reticular Layer (80% of dermis)

    • Contains sweat and sebaceous glands, hair follicles, blood vessels, nerves, collagen, and elastin.

Subcutaneous Hypodermis

• Layer underneath the dermis, anchors skin to structures.

• Contains adipose tissue for cushioning and insulation.

• Houses nerve endings sensitive to deep pressure and high-frequency vibration.

Conclusion

• Acknowledgment of the audience: Ngā mihi (Thank you).
  - Course Part 1 concluded.