Skin Flashcards
What system does skin belong to?
Integumentary.
What are the 3 layers of the skin?
- Epidermins (outside layer).
- Dermis (middle layer).
- Hypodermis (inside layer).
What is the structure of skin?
1) . Hair shaft.
2) . Pore of sweat gland duct.
3) . Endocrine sweat gland (in dermis).
4) . Pacinian corpuscle (in dermis).
5) . Hair follicle receptor (in dermis).
- Epidermis.
- Dermis.
- Hypodermis.
What are the 4 main types of cells that make up the epidermis?
- Keratinocytes.
- Melanocytes.
- Merkel cells.
- Langerhans cells.
What proportion of the epidermis is keratinocytes and melanocytes?
- Keratinocytes = 90%.
- Melanocytes = 8%.
What is the function of keratinocytes?
Produce keratin = makes skin waterproof.
What is the function of melanocytes?
Produce the pigment melanin.
What is the function of merkel cells?
Act as sensory receptors.
What is the function of langerhans cells?
Are involved in immune response.
Where is the stratum corneum found?
In the epidermis.
What does melanin do?
Contributes to skin colour and protects from UV light.
What are the physical properties of the epidermis?
- Protect the warm, moist internal environment.
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Where is keratinocytes formed?
Stratum basale.
How do keratinocytes divide?
By mitosis.
What happens as keratinocytes mature?
- Change shape.
- Lose their nucleus.
- Form flattened dead cells filled with keratin.
What is keratin?
Hard protein that makes up our nails and hair.
What helps keep the epidermis intact in healthy skin?
Balance of water and lipid content.
What is sebum?
- Oily substance containing antimicrobial agent.
- Mixture of lipids = helps keep the skin hydrated.
What is an antimicrobial?
An agent that kills microorganisms/inhibits their growth.
What are the cells in the dermis?
- Fibroblasts.
- Mast cells.
- Phagocytes.
- Lymphocytes.
What is the function of fibroblasts?
Secrete collagen and elastin.
What is the function of mast cells?
- Play a key role in non-specific immune responses.
- Secrete inflammatory mediators.
What is the function of phagocytes?
Destroy bacteria by a process of ‘cell eating’.
What is it called when phagocytes destroy bacteria?
Phagocytosis.
What is the function of lymphocytes?
- White blood cell involved in immune surveillance.
- Involved in specific immune response.
What does the dermis contain?
- Lymph vessels.
- Nerve endings.
- Hair follicles.
- Glands.
What are the properties of the dermis?
- Store water (hydration).
- Dense connective tissue.
- Collagen = tensile strength + support.
- Elastin fibres = toughness + flexibility.
How does a blister form?
Dermis separates from the epidermis –> tissue fluid builds up between the layers.
