Lecture 2 - Skin Flashcards
What are the contents of the skin along its thickness?
Thin epithelium: epidermis
Thicker connective tissue layer: dermis - mesodermal
Hypodermis (subcutis) - connective tissue between skin and deeper structures which is also mesodermal
Appendages (hair, nails, sweat and sebaceous glands)
What are skin epidermal cells made up of?
Stratified squamous keratinised epithelium
What are the layers of epidermis?
CLGSB
Corneum
Lucidum
Granulosum
Spinosum
Basale
Why do burn victims lose lots of fluid?
Skin acts as a barrier for water loss. When it is burned off lots of water is lost from that area.
What is contained in the stratum corneum?
Keratin layer with dead cells embedded in dense protein matrix and spaces are filled with lipids.
What is contained in the stratum lucidum?
Only visible in thicker skin and nuclear outlines breaking down. Flattened cells still visible.
Which layer has spiny connections with desmosomes holding cells together to prevent sloughing off of skin when rubbed together?
Stratum spinosum
Which layer has cells full of keratohyalin granules with lipids released to fill intracellular space preparing to keratinise?
Stratum granulosum
What is contained in the stratum basale?
Layer of columnar or cuboidal rapidly dividing cells which replace epidermis every 3 - 4 weeks
How are thick and thin skin different?
Difference is in corneal layer thickness
What are the layers of dermis and what do they contain?
Papillary dermis contains loose CT as well as capillaries and nerve endings.
Reticular dermis contains dense CT as well as thick collagen fibers aligned along lines of tension (Kraissl lines) This is important for surgery because parallel lines heal faster.
Hypodermis contains loose CT and fat.
What do melanocytes do?
They produce melanin.
Where do melanocytes originate?
They are of neural crest origin. They transfer melanosomes to epidermal cells.
What controls pigmentation of melanocytes?
Pigmentation is under control of light as well as hormones produced by pituitary and adrenal glands.
Diseases of which 2 endocrine organs can cause pigmentation changes in skin?
Adrenal and pituitary glands.