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36 Cards in this Set
- Front
- Back
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What is skin?
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10% of our body weight
FUNCTION: protection, temperature regulation, sensation, excretion of water and salts, vitamin D production from sunlight |
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What are the layers of skin?
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Epidermis
Dermis Hypodermis (below the skin) |
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What is Hypodermis?
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Not part of skin but only ATTACHES skin to underlying muscle and bone
consist of loose CT mainly collagen fibers cells: fibroblasts, adipocytes, macrophages major site of fat deposition 50% of body's stored fat (adipocytes) good vascular supply (alot of blood cells) supplies skin with nerves |
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What is the dermis?
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connects the skin to the hypodermal layer
mainly of dense IRREGULAR CT fibers - collagen, elastic & reticular (some) cells - (similar to hypodermis) except few adipocytes CONTAINS: nerves, vessels, and glands |
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What are the layers of dermis?
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Reticular - dense irregular MAIN LAYER (bigger layer)
Papillary - loose connective CT, forms papillae, finger-like projections |
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What is the epidermis?
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composed of KERATINIZED, stratified squamous epithelium
Major cell type: keratinocyte (produces keratin) |
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What is keratin?
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keratin has a high sulfur content (strong bonds)
insoluble in water hard to digest LOCATION: hair and skin |
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What are other cell types in the epidermis?
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melanocytes
Langehans cells Merkel's cells |
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What are melanocytes?
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produces pigement
colors |
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What are langerhans cells
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to fight infections
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What are Merkel's cells
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to have fine sensory feeling
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What are the five layers of the Epidermis?
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stratum corneum
stratum lucidum stratum granulosum stratum spinosum stratum basale |
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What is stratum corneum?
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consist of dead skin cells
25-30 rows |
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what is stratum lucidum?
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thin, clear layer
ONLY in high friction areas (palms, soles of feet) |
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What is stratum granulosum?
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thin, DARK layer (2-5 rows)
cells undergo Apoptiosis – program cell death (self-destruction) |
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What is stratum spinosum?
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cells are spiny
starts producing keratin (8-10 rows of kerationcytes) |
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What is Stratum basale?
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Deepest (1 row)
site of cell division (mitosis) closest to the basement membrane |
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How is skin based thick or thin?
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it is based on the thickness of the epidermis
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What is thick skin?
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found in palms, soles of feet
the paillae of the dermis form parallel ridges (as in fingerprints) Papilla – makes finger prints |
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What is thin skin?
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found wherever thick skin isn't
No parallel ridges form by dermis HAIR is only found on thin skin |
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what determines skin color?
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abundance of skin pigment (Melanocytes)
amount of blood circuclating through skin (blushing means alot of circulation) the thickness of the stratum corneum |
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What is the major skin pigment?
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melanin (brown pigment)
PRODUCES by melanocytes ABSORBED by kerationocytes amount = genetic factors, exposure to UV increases sun burn = a lot of melamin |
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What are other substances cause pigmentation?
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carotene (yellowish - food CARROTS)
disease jaundice |
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What are nails?
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found at distal ends of the digits
CONSIST: nail root, distal nail body FUNCTION: protect of digits, aid in grasping, defense (scratching), display (female) |
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What are hair?
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dense hair covering most of the body = FUR
hair grows = 2mm per week 2 cycles: active growth and resting phase scalp hair has active phase = 4 yrs hair on eyebrows - few months |
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What is the two types of hair
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terminal = long, thick, pigmented
vellus = short, fine, unpigmented |
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Why is hair needed?
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display (more mates)
insulation (temperature control) protection against friction/foreign substances dispersion of glandular secretions evolutionary remant (eventually hairless) |
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What is the structure of hair?
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hair shaft
hair hair follicle |
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What is the hair shaft?
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hair seen above the skin
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What are the three layers of hair?
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Medulla = center of hair
cortex = surroudning the medulla cuticle = single layers overlap "roof like" |
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What are the glands associated with skin?
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sebaceous glands
sweat glands |
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What are sebaceous glands?
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prevent water lossage
produce sebum (OILY) duct ends in a hair follicle (exocrine) provides oil to skin and hair holocrine secretion (whole cells break up to form the product) |
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What are 3 types of sweat glands?
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Eccrine
apocine ceruminous |
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What are eccrine glands?
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produce SWEAT
open onto skin surface Releases: Water, salt, and waste produces (ammonia, urea, lactic acid) |
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What are apocine glands?
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produce organic secretion
fatty substance & proteins; pheromones open into hair follicles; mostly to anal & genital areas |
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What are ceruminous glands?
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modified APOCINE sweat gland
produces EARWAX |
