Integumentary tissue pt 2 Flashcards
4 accessory structures of the skin
- Sweat glands (merocrine/apocrine)
- Oil glands (sebaceous glands)
- Hairs + hair follicles
- Nails
Sweat glands
Sudoriferous
2 types:
- Eccrine (merocrine): abundant on palms, soles, and forehead
- sweat: 99% water, NaCl, vitamin C, antibodies, dermcidin, metabolic wastes
- ducts connect to pores
- function in thermoregulation
- emotional sweating “cold sweating” - Apocrine sweat glands: confined to axillary + anogential areas
- Sebum: sweat + fatty substances + proteins
- ducts connect to hair follicles
- functional from puberty onward, body odor
- specialized apocrine glands: ceruminous glands (external ear canal and secretes cerumen - ear wax), mammary glands
Sebaceous glands
Oil glands
- widely distributed
- develop from hair follicles
- become active at puberty (hormones)
- sebum: oily holocrine secretion, bactericidal, softens hair + skin
- if sebum blocks duct -> white head
Acne
Sebaceous oil glands on the hair follicle and all the sebum that is supposed to be secreted gets blocked and infected creating acne (white head)
Hair
Function:
- alerting body to presence of insects on skin
- guarding scalp against physical trauma, heat loss, sunlight
Distribution:
- entire surface except palms, soles, lips, nipples, and portions of external fenitalia
- eye lashes shield eyes
- nose hairs filters large particles
Anatomy of hair
Columns of dead, keratinized epidermal cells
- shaft: projects above surface of the skin
- root: penetrates into dermis/subcutaneous layer
- 3 concentric layers:
1. medulla: inner, lacking in thinner hair
2. cortex: middle, major part of shaft
3. cuticle: outermost, heavily keratinized
Hair follicle and its 4 parts
- Epithelial root sheath
- external root sheath: continuation of epidermis
- internal root sheath: produced by matrix - dermal root sheath: dense dermis surrounding hair follicle
- bulb: base of ahir follicle, houses papilla of hair
- papilla: areolar CT + bloody supply - arrector pili: smooth muscle, attaches to dermal root sheath, hair stands up
2 types of hair
- Vellus: pale, fine body hair of children + adult females
- Terminal: coarse, long hair of eyebrows, scalp, axillary, and pubic regions (face/neck of males - testosterone)
Hair growth and its 3 stages
Growth cycle: growth, regression, rest stages
- Active: cells of hair matrix divide. existing cells push upward, hair grows. 2-5 years
- regression: cells of matrix stop dividing, follicle atrophies, hair stops growing. 2-3 weeks
- resting: final stage before old hair falls out and new hair begins to grow. 3 months
Structure of nail (4 things)
Made of hard keratin
1. Nail body: visible portion of nail
- free edge: part extending past end of d
- Nail root: portion buried in a fold of skin
- lunula: whitish, thickened crescent shaped area - Hyponychium: nail bed, secures nail to fingertip
- Eponychium: cuticle, narrow band of epidermis adheres to nail wall
- corresponds to hooves/claws of animals
Skin cancer and 3 major types
- Most tumors are benign (not metastasize)
- Risks: overexposure UV, frequent irritation of skin, 1 in 5 develop skin cancer
- Basal Cell carcinoma: least malignant, most common, stratum basale
- Squamous cell carnioma: second most common, stratum spinosum
- Melanoma: most dangerous, melanocytes, least common
Melanoma
ABCD
A: Asymmetry; 2 sides of pigmented area do not match
B: Border exhibits indentations
C: Color is black, brown, tan, and sometimes red/blue
D: Diameter is larger than 6 mm (size of a pencil eraser)
3 burn degrees
1st degree: epidermis, redness, swelling, pain, sunburn
2nd degree: upper dermis, blisters
3rd degree: full thickness, gray/white/black, nerve endings destroyed, graft may be necessary, getting to the hypodermis (burned epidermis, dermis)
Immediate threat:
1. dehydration and electrolyte imbalance, leading to renal shutdown and circulatory shock
2. Infection
Rule of Nines
Estimate volume of fluid loss from burns
11 areas of body each account for 9% of body area
Partial-thickness burns
1st degree
- epidermal damage only
- localized redness, edema (swelling), and pain
2nd degree
- epidermal and upper dermal damage
- blisters appear
Full thickness burns
3rd degree
- entire thickness of skin damaged
- gray-white, cherry red, black
- no initial edema/pain
- skin grafting usually necessary
3 steps of tissues repair
- Inflammation
- Release of inflammatory chemicals
- Dilation of blood vessels
- increase in vessel permeability
- clotting occurs
- positive feedback - Organization + restored blood supply
- blood clot replaced w/ granulation tissue
- epithelium begins to regenerate
- fibroblasts produce collagen fibers to bridge gap
- debris phagocytized - regeneration + fibrosis
- scab detaches
- fibrous tissue maturesl epithelium thickens and begins to resemble adjacent tissue
- results in a fully regenerated epithelium w/ underlying scar tissue
