13 - Integument Flashcards
What are the 3 major regions of the Integument?
- epidermis - outermost
- dermis - middle region (areolar & reticular CT)
- hypodermis - deepest region (adipose & areolar CT)
What are the functions of the integumentary system?
- Protection - chemical (low pH, glycolipid waterproofing), physical and mechanical barrier
- Cutaneous sensation - called exoreceptors b/c they sense external touch & pain
- Body temperature - blood vessel contstriction & sweat gland secretions
- Metabolic functions - synthesizes vitamin D in dermal blood vessels
- Blood reservoir - skin blood vessels store up to 5% of the body’s blood volume
- Excretion - limited amounts of nitrogenous wastes are eliminated from the body in sweat
What are the 4 cell types in the epidermis?
- keratinocytes - produce keratin
- melanocytes - produce melanin
- Langerhans’ cells - macrophages
- merkel cells - touch receptors
What are the layers of the Epidermis? from superficial to deep
- stratum corneum
- stratum lucidum (thick skin ONLY)
- stratum granulsoum
- stratum spinosum
- stratum basale
What are the 2 types of granules in stratum spinosum? what do they do?
- Keratohyaline granule - involved in cross-linking keratin & cellular dehydration
- meshwork of keratin
- Lamellar granules - waterproofing glycolipid granules that is spewed into the extracellular space
- Water proofing agents
What cells are in the Dermis?
- fibroblasts
- macrophages
- mast cells
- WBC
What are the layers of the Dermis?
- papillary layer - loose areolar CT
- reticular layer - dense irregular CT
What is present in the Papillary layer of the Dermis?
- areolar CT - collagen & elastic fibers
- dermal papillae
What are Dermal Papillae?
- superior surface peg-like projections
- dermis -> epidermis
- contain: capillary loops, meissner’s corpuscles, free nerve endings
What is in the Hypodermis layer?
- composed of adipose & areolar CT
- blood vessel layers - involved in thermoregulation
What is in the Reticular layer of the Dermis?
- collagen fibers
- elastin fibers
What are the 3 pigments that contribute to skin colour?
- melanin - yellow to black colour
- carotene - yellow to orange colour
- hemoglobin - reddish pigment
What are the 4 gland types?
- Sudoriferous sweat glands
- Ceruminous glands
- Mammary glands
- Sebaceous (oil) glands
Apocrine vs. Eccrine
- Apocrine - larger, highly vascularized, secrete along hair shaft, viscous secretion
- Eccrine (merocrine) - over most of body, open directly onto skin surface, hypotonic filtrate of the blood
What are Ceruminous Glands?
- Secrete cerumen or earwax - thought toe deter insects & block entry of foreign material
- Combo of apocrine & eccrine
What are Mammary Glands?
- Specialized sweat glands that secrete milk
- Modification of apocrine
- Stimulated by prolactin to produce milk
What are Sebaceous glands?
- Holocrine type oil secretion called sebum (made of cholesterol, proteins, fats & salts)
○ Lose cell as mode of secretion - Keeps hair & skin soft & pliable & inhibits growth of bacteria & fungi (ringworm)
- Activated during puberty when androgens begin to rise
○ Sensitive to DHT, Testosterone - Acne caused by a clogged sebaceous gland pore
What are the layers in the hair follicle? (starting at medulla)
- Medulla > Cortex > Cuticle > Internal epithelial root sheath > external epithelial root sheath
How does the hair alert the body to insects on the skin?
- sensory nerve endings called hair follicle receptor or root hair plexus wrap around each bulb
- if the hair is bent, stimulates endings -> suggests something is on skin
What are Hair papilla?
- dermal tissue that protrudes into the hair bulb & has capillaries
- type of CT
What is the Hair Matrix?
- actively dividing area that produces hair, as cells are pushed upwards they become increasing keratinized & die
- similar to basale layer
What causes hair colour?
- pigment made by melanocytes at base of hair follicle
- blond & red have little eumelanin
- black hair has lots of eumelanin
- red hair also has pheomelanin
What are the 3 steps in the Hair Growth Cycle?
- Growth Stage - cells of matrix differentiate, keratinize & die, 2-6 years
- Resting stage - hair growth stops, lasts for 3 months on scalp
- After resting stage - hair falls out, replaced & new growth stage
What is the structure of the nail?
- modification of the epidermis made of hard keratin
- nail cells are produced by matrix
- nail cells become heavily keratinized & nail body slides over nail bed
What are the types of Cancer & what cells are they derived from?
- carcinoma - epithelial cells
- sarcoma - connective tissue or mesenchymal cells
- lymphoma & leukemia - hematopoietic cells
- germ cell tumor - pluripotent cells
- blastoma - embryonic tissue
What are the 3 major types of skin cancers?
- basal cell carcinoma - most common, stratum basale, slow growing & often does NOT metastasize
- squamous cell carcinoma - stratum spinosum, grows rapidyly & metastisizes if not removed
- melanoma - melanocytes, highly metastatic & resistant to chemotherapy
What is a crucial risk factor for nonmelanoma skin cancer?
- disability of the p53 gene (tumor suppressor gene)
What is the ABCD rule for melanoma?
- A - asymmetry
- B - border (irregular & indentations)
- C - colour (black, brown, tan)
- D - diameter (larger than 6mm)
What is the rule of 9 for burns?
- anterior/posterior head & neck = 9%
- anterior/posterior upper limbs = 18%
- anterior/posterior trunk = 36%
- anterior/posterior legs = 36%
Burns are considered critical when…
- Over 25% of body has 2nd degree burns
- Over 10% of body has 3rd degree burns
- 3rd degree burns on face, hands or feet
What are potential fatal complications from burns?
- shock
- infection
- electrolyte imabalance
- respiratory distress
