Structure of the Skin
Key Components of Skin Structure
1. Epidermis
- Outermost layer of the skin
- Made up of stratified squamous epithelium
- Contains:
- Keratinocytes (produce keratin)
- Melanocytes (produce melanin)
- No blood vessels
The epidermis is constantly renewing itself, with cells moving from deeper layers to the surface over about 28 days.
2. Dermis
- Located beneath the epidermis
- Rich in:
- Blood vessels
- Nerve endings
- Hair follicles
- Sebaceous glands
- Sweat glands
Think of the dermis as the skin's "supply depot" - it contains everything needed to keep the skin functioning!
3. Subcutaneous Layer (Hypodermis)
- Deepest layer
- Composed mainly of:
- Adipose tissue (fat)
- Loose connective tissue
- Larger blood vessels
Important Structures to Identify
Blood Vessels
- Arterioles and venules form extensive networks
- Help regulate body temperature
- Provide nutrients to skin cells
Nerve Endings
- Various types present:
- Thermoreceptors (temperature)
- Nociceptors (pain)
- Mechanoreceptors (pressure/touch)
Glands
- Sweat Glands (Eccrine)
- Produce watery sweat
- Important for thermoregulation
- Sebaceous Glands
- Produce oil (sebum)
- Keep skin waterproof
- Lubricate hair
Students often confuse eccrine (sweat) and sebaceous glands. Remember: eccrine = watery sweat, sebaceous = oily secretions.
Hair Follicles
- Extend from epidermis into dermis
- Associated with:
- Arrector pili muscles
- Sebaceous glands
When labeling diagrams, make sure to identify both the structure and its location within the correct skin layers
