Skin and Dermatology Flashcards
What are the layers of the epidermis? (Top –> bottom)
- Stratum corneum
- Stratum lucidem
- Stratum granulosum
- Stratum spinosim
- Stratum basale
What are the embrylogical origins of skin?
From ectoderm
What is the location of the hypodermis?
- Lowest layer of the skin
- Also known as the sub-cutaneous (superficial fascia)
What is the structure of the hypodermis?
- Mainly contains adipose tissue (some neurovascular bundles/lymphatics
- Loose connective tissue (fibroblasts/ macrophages/ fibres)
What are the functions of the hypodermis?
- Provides energy store- generate heat
- Insulator for underlying muscle heat generation
- Shock absorber- cushions impact/ protection
- Connects skin to underlying muscle and bones
- Makes hormones, eg. leptin to control eating habits
What causes wrinkles in the skin? Responsible for hypothermia in the elderly?
Thinning of the hypodermis
What are the functions of the skin?
- Protection and repair
- Temperature regulation and excretion of waste products
- Lubrication
- Storage
- Vitamin D synthesis
- Absorption
- Aesthetics
- Sensation
How does the skin provide protection and repair?
- Epidermis by keratinocytes
- UV protection by melanocytes
- Invasion by Langerhans’ cells
- Papillary dermis by fibroblasts (wound healing)
- Reticular dermis/hypodermis by fibroblasts/mast cells and macrophages
How does the skin regulate temperature and excrete waste products?
- Sweat glands secrete urea, sodium chloride and water plus some CO2
How does the skin lubricate?
Sebaceous sweat glands release oil onto surface (also acts as water barrier)
What does the skin store?
White adipose cells that provide energy through lipids
How is the skin involved in Vitamin D synthesis?
Cholecaliciferol produced in the skin is converted into 25-hydroxyl cholecalciferol (25-OH) by the liver and then into 1,25-hydroxyl cholecalciferol in the kidney
