Lecture Notes: The Integumentary System
Overview
- Largest Organ: The skin
- System: Integumentary System
- Functions:
- Regulates internal body temperature
- Maintains fluid balance
- Acts as a physical barrier
- Site for vitamin D synthesis
- Sensory functions (e.g., detecting touch)
Structure of the Skin
Layers of the Epidermis
- Stratum Corneum
- Composed of dead, cornified cells
- Continuously sloughed off
- Site for new cell replacement
- Stratum Lucidum
- Found in thick skin (soles of feet, palms)
- Transparent layer
- Stratum Granulosum
- Keratinocytes flatten and accumulate granules
- Forms a water-protective layer
- Stratum Spinosum
- Houses Langerhans cells (consume bacteria, worn-out cells)
- Appears spiny under a microscope
- Stratum Basale
- Deepest layer
- Contains basal cells, melanocytes, Merkel cells
- Connects to the dermis
Dermis
- Composition: Connective tissue, blood vessels
- Functions: Binds body structures
- Key Proteins:
- Collagen: Structural support
- Elastin: Elasticity
- Sub-layers:
- Papillary Layer: Looser connective tissue
- Reticular Layer: Dense connective tissue
Hypodermis
- Also known as: Subcutaneous tissue
- Composition: Adipose tissue
- Function: Insulation, connects skin to underlying structures
Accessory Structures
- Sweat Glands: Regulate body temperature through perspiration
- Sebaceous Glands: Produce oil for skin lubrication
- Hair Follicles: Hair growth from mitosis in the hair bulb, composed of keratin
- Nails: Growth from mitosis in the nail root, protects tips of fingers and toes
Health Implications
Skin Cancer
- Types:
- Basal Cell Carcinoma: From basal cells
- Melanoma: From melanocytes
- Squamous Cell Carcinoma: From squamous cells
- Causes: UV radiation exposure, DNA damage
Burns
- Classification:
- First-degree: Affects epidermis
- Second-degree: Extends into epidermis and upper dermis
- Third-degree: Penetrates deeper layers
- Fourth-degree: Affects deeper tissues
- Concerns:
- Impairs skin functions (fluid retention, protection)
- Susceptible to infection
Conclusion
- Importance of understanding the integumentary system for the ATITs exam
- Additional resources available at nurse store.com
- Encouragement to ask questions for further clarification
These notes summarize the key points from the lecture on the integumentary system, focusing on skin structure, function, health implications, and exam preparation.