23. Integumentary System Flashcards
(29 cards)
What are the three main layers of skin?
Epidermis, Dermis, Hypodermis (subcutaneous layer).
What are the five layers of the epidermis (outermost to innermost)?
1) Stratum Corneum; 2) Stratum Lucidum (only palms/soles); 3) Stratum Granulosum; 4) Stratum Spinosum; 5) Stratum Basale.
What is the function of the Stratum Corneum?
Outermost hydrophobic layer.
What is the Stratum Lucidum?
Layer only present in palms of hands and soles of feet.
What happens in the Stratum Granulosum?
Skin cells lose organelles, begin dying, fill with keratin.
What is the function of the Stratum Spinosum?
Provides skin strength and flexibility; cells held by desmosomes.
What happens in the Stratum Basale?
Deepest epidermal layer where new skin cells are formed.
What does the dermis do?
Second layer; highly vascularized; connected to epidermis via basement membrane.
What are the two regions of the dermis?
Papillary region and Reticular region.
What is the Papillary region?
Contains vascular network with upward papillae; supplies nutrients, regulates temp; papillae have Meissner’s corpuscles (touch receptors).
What is the Reticular region?
Dense connective tissue with collagen and elastic fibers; packed with glands, sweat gland ducts, fat, and hair follicles.
What is the Hypodermis (subcutaneous layer)?
Areolar and adipose tissue; fat storage, heat insulation, shock absorption; has pressure nerve endings and blood vessel passage.
What are melanocytes?
Transfer melanin pigment to keratinocytes.
What are Merkel cells?
Attach to sensory neurons; function in touch sensations.
What are keratinocytes?
Produce keratin; waterproof skin.
What are Langerhans cells?
Interact with immune cells in the skin.
What are eccrine sweat glands?
Open directly to skin surface; found on most skin; regulate temperature via perspiration and urea elimination.
What are apocrine glands?
Open to hair follicles; viscous secretions; found in armpits, pubic region, nipples.
What are ceruminous glands?
Produce wax in ear canal to block entrance of foreign material.
What are sebaceous glands?
Connected to hair follicles; secrete oil (sebum) that discourages microbial growth.
What are mammary glands?
Secrete milk; unique to mammals.
What are the functions of the skin?
Thermoregulation, sensory input, protection, vitamin D synthesis, immunity, excretion.
How does thermoregulation work?
Capillaries dilate to release heat and constrict to preserve it; sweat evaporates to cool; goosebumps trap heat.
What sensory inputs does skin detect?
Temperature, pressure, pain, touch.
