Ch.5 - Integumentary System (Skin) Flashcards
2 layers of skin
Epidermis and dermis
Skin is made up of 2 parts:
Cutaneous membrane and hair/nails/multicellular exocrine glands
Classification of epidermis epithelial cells
Superficial stratified squamous epithelium
What makes up a membrane?
Epithelial sheet + underlying connective tissue proper
What are plexus?
Network of blood vessels or nerves
How do microvascular plexus look in skin?
2 horizontal plexuses
What are 2 horizontal plexuses?
Superficial vascular and deep
Describe superficial plexus
Group of microvascular plexus lying just below junction between dermis and epidermis
Describe deep plexus
Lies at interface of dermis and hypodermis
3 characteristics of epithelial tissue
Avascular, highly regenerative, and lots of nerves
What is desiccation?
Drying out by evaporation
Defense mechanisms against micro-organisms
Tight junctions
Langerhan’s cells
Low pH of skin secretions
Bacterial secretions
How do tight junctions help integumentary system fight micro-organisms?
(The net looking junction) Resist microbes by preventing them from sneezing through space btw cells
How do Langerhan’s cells help against micro-organisms?
Help activate immune systems
What helps skin protect itself from UV rays?
Melanin
Describe how skin regulates body temp (thermoregulation)
Cold environment = superficial vascular plexus constricts
Warm environment = superficial vascular plexus dilates allowing heat loss
What is calcitriol?
Active form of vitamin D, helps maintain calcium homeostasis by absorbing more calcium
Where is vitamin D3 created?
In dermal blood vessels
What are keratinocytes?
In epidermis, Produce large amounts of keratin
What are melanocytes?
In epidermis, make melanin (skin tone)
What are Langerhan’s cells?
In epidermis, they activate immune system
What are merkel cells?
In epidermis, touch receptors (allow feelings)
What is keratin?
Protein that makes intermediate filaments of cytoskeleton
Layers of epidermis in order from deep to superficial
Stratum basal Stratum spinosum Stratum granulosum Stratum lucidum Stratum corneum
Epithelial classification of stratum basale layer
Single row of mainly keratinocytes, some melanocytes, and sometimes Merkel cells
What are projections from melanocytes?
Dendrites, extend from stratum basale to stratum spinosum
What do the melanocyte dendrites do?
Melanin is transported down it and released by exocytosis.
What are melanosomes?
Membrane-bounded vesicles that carry melanin through dendrites of melanocytes
How does melanin leave the melanocyte?
It’s produced in the cell, transported down dendrites and melanosome, then released from melanosome by exocytosis
Cells that make up stratum spinosum
Keratinocytes - tonofilaments
Langerhan’s
Cells make up stratum granulosum
Keratohyaline granules - break down tonofilaments
Lamellar granules - waterproof
Cells make up stratum lucidum
Dead cells
Cells make up stratum corneum
Dead cells covered in glycolipids
Describe papillary later of dermis
Areolar connective tissue proper,
Dermal papillae
Describe reticular layer of dermis
Dense irregular connective tissue,
Collagen fibers bundled,
Elastic fibers loosely arranged
Langer’s lines
Way of secretion by sebaceous glands
Halocrine
Way of secretion by sudoriferous glands
Mereocrine, exocytosis
