Burns (skin) Flashcards
what are the 3 layers of the skin
epidermis
dermis
hypodermis/subcut tissue
Describe the 4 or 5 layers of the epidermis.
Stratum corneum – more than 25 layers of dead squamous cells
(Stratum lucidum – 3-5 layers of translucent dead cells, only found in thick skin)
Stratum granulosum – 2-5 layers of flat diamond shaped cells
Stratum spinosum – 8-10 layers of many sided cells
Stratum basale – single layer cuboidal, basement membrane attaches to the dermis
Keratinocytes, melanocytes, merkel cells, and langerhan’s cells are all found in the epidermis, Describe them, e.g. function, where they are found.
Keratinocytes make up around 90% of epidermis. They are epithelial cells which produce keratin. This makes the skin durable and waterproof, protecting it. They are produced in the stratum corneum, nails & hair.
Melanocytes make up around 8% of epidermis, and produce melanin
Merkel Cells are receptors in the nervous system called mechanoreceptors, and are associated with nerve endings
Langerhans’ Cells are immune cells that capture & process microbial antigens
what is keritanisation
Renewal of the epidermis is called Keratinisation. The cells in the stratum basale divide, and change shape and composition as they move from deep to superficial. As they do so they gain keratin and die. This can go wrong in diseases.
What is the dermis?
The dermis is strong, flexible, connective tissue rich in collagen and elastic. It contains: fibroblasts, macrophages, a few adipocytes, nerve endings, Blood vessels, glands, smooth muscle, and lymphatics.
what is the hypodermis/subcutaneous layer
o Areolar and adipose tissue
o Large blood vessels and nerves
what are the 4 stages of wound healing
Vascular response/ haemostasis
Inflammatory response
Proliferation: Reconstruction Phase
Maturation
what does the vascular response/haemostasis do
conserves blood supply through blood clotting
describe the inflammatory response
Lasts approx. 4-5 days, Requires both energy and nutrition, Stage can be delayed in infected and necrotic wounds.
• Vascular response: vasodilation, increased permeability, gives wound site erythema, oedema and warmth
• Cellular response: leukocytes move into wound bed, arrival of macrophages to produce growth factors PGDF and protease, phagocytosis
describe proliferation
Development of granulation tissue, Production of collagen fibres, Angiogenesis (growth of new blood vessels), Epithelial cells multiply and migrate over the surface, Wound edges pulled together by contraction (approx 5/6th day), This stage can start before the inflammatory stage is completed. When there is a prolonged inflammatory stage, over granulation can occur
describe maturation
Wound becomes less vascularized, Collagen fibres are reorganize, Synthesis of new collagen, Tensile strength increases
what happens when skin is burnt?
When the skin is burnt, some or all of the cells which form the skin are damaged. This can result in a break in barrier of the skin, loss of fluid, Inflammation (redness and swelling), Progressive damage through tissue, pain as dermis damaged (contains sensory nerves).
what is a first degree burn
burn to superficial epidermis, function not affected, Red, non-blistered skin, 3-5 days healing, E.g. Sunburn, scalds
what is a second degree burn
deep dermal, function affected, Blisters and some thickening of the skin, 3-5 weeks healing (without infection)
what is a third degree burn
all three layers affected, high infection risk, widespread thickness with a white or charred and leathery appearance. Usually requires a skin graft. E.g. Flames, Chemical burns, electricity.
