10.0 Integument system Flashcards
what are the 3 major regions of the integument
Epidermis - outermost superficial region
Dermis - middle region
Hypodermis (superficial fascia) - deepest region
what are the cells of the epidermis
- composed of kertainized stratified squamous epithelium
- 4 cell types and 4-5 layers
Keratinocytes: produce fibrous protein keratin
melanocytes: produce bown pigment melanin
langerhans cells: macrophages, part of immune system
merkel cells: function as touch receptors in association with sensory nerve endings
what are the layers of the epidermis
dermis, stratum basale, stratum epinsosum, stratum granulosum, stratum corneum
describe the stratum basale
- basal layer
- deepest epidermal layer, firmly attached to dermis
- consists of single row of youngest keratinocutes cells undergo rapid division, hence its alternate name stratum germinativum
*single layer of cells
describe the stratum spinosum
aka prickly layer
- keratinocytes in this layer appear irregular in shape
- web-like system of intermediate filaments attached to desmosomes
- melanin granules and langerhans cells are abundant in this layer
*area where cells are aging
where are melanocytes located
ONLY in basal layer
- have membrane proejctions that go into stratnum spinosum
- keratinocytes take up melanin granules
what are the two types of granules in the stratum spinosum
keratohyaline granules: involved in cross linking keratin and cellular dehydration
*make tissue stronger by cross linking keratin
lamellar granules: waterproofing glycolipid grandules that are spewed into extracellular space
*main reason the skin is waterproof
describe the stratum granulosum
*as cells go clsoer to skin go farther from nutrient soruce
- cells flatten, their nuceli, organelles begin to dsiintegrate
- accumulate keratohyaline granules and lamellar granules
- PMs thicken, cytosol proteins bind to inner membrane face and released lipids coats their external surfaces
- above stratum granulosum, the epidermal cells are too fat from dermal capillaries and die
*process thought of as toughening up
what is the stratum lucidum
- celar layer
- thin trasnparent band superficial to stratum granulosum
- few rots of flat dead keratinocytes
- Oily layer that is the result of exocytosis of lamellar bodies
only in thick skin: palsm fo ahnds and soles of feet
**only in thick skin like palsm of hands and soles of feet, not elsewhere
describe the stratum corneum
- horny layer
- outermost layer of keratinized cells (3/4 thickness of epidermid)
*most of epidermis is stratum corneum
- dandruff is the shingle-like remnants of the stratum corneum that shed from scalp and dry skin
functions include:
- > waterproofing (glycolipids)
- . protection from abrasion and penetration (keratin and thickcened plasma mem)
- rendering body less sensitive to biolgoical and chemical and physical assults
what are the alyers of the epidermid
most superfisical -> deep
corneum, lucidum, granulosum, spinosum , basale
*come lets get sun burnt
*lucidim is only in thick skin like palsm and soles
what is the dermis
- contains strong, flexible connective tissue
- cell ypes inclueL fibroblasts, macrophages, mast cells and WBC
- has two layers:
- > Papillary (loose areolar conencive tissues)
- > returcular layer (dense irregular)
describe the appillary layer of the dermis
- areolar connective tissue (collagen and elastic fibers)
- sueprior surface contains Peg-like projections called dermal papillae
- dermal papillae contains: capillary loops, meissner corpuscles and free nerve endings
describe the reticular layer of the dermis
- apporx 80% of the thickness of skin
- dense irregualr conenctive tissue
- collagen fibers add strength and resiliency
elastin fibers provide stretch recoil properties
what is the hypodermis
- subcutaneous layer deep to the skin
- composed of adipose and areolar conenctive tissue
- blood vessles go through this layer bc has fat to keep them warm -> can reg temp by constriction when cold and promoting blodo flow when warm
what causes variations in skin colour
3 pigments: melamin, carotene and hemoglobin
- Melanin:
- yellow - black pigment responsible for dark skin colours
- freckles and males are local accumulatoins of meanin in karatinocyttes
- Carotene:
- yellow-orange pigment, most obvious in the palms and soles of feet
- accumulates in corneum and hypodermis (high conc of fat)
- yellow-orange pigment, most obvious in the palms and soles of feet
- hemoglobin:
- Reddish pigment responsible for the pinkish hue of the skin
- *cyanosis due to poorly oxygenated blood (blueish purple)
what are the 4 types of sweat glands
sudoriferous glands, ceruminous, mammary and sebaceous
descibe sudoriferous sweat glands
2 typres
- Apocrine glands
- viscous secretion (milky yellowish colour)
- activity can be increased by sexual foreplay (axilla, perianal)
- associated with hair follicle
- Eccrine (merocrine) glands
- secretion of hypotonic filrate of the blood
- helps to prevent overheating (all over but more in axilla)
- coiled strucute with tube
desrcibe the ceruminous gland
Secrete cerumen or earwax
thought to deter insects and block entry of foreign material
describe mammary glands
specialized sweat glands that secrete milk
describe sebaceous oil glands
- holocine oil secretion called sebum (made of colesterol, proteins, fats and salts)
- keeps hair and skin soft and pliable, inhibits growth of bacteria and fingu (ringworm)
- activated during puebrty when androgens begin torise
- acne caused by clogged sebaceous gland pore
what are the functions of hair
Alerting the body to presence of insects on the skin
Guarding the scalp against trauma, heat loss and sunlight
Eyelashes shield the eyes and nose hairs filter large particles
what locations on the body do not have hair
Palms, soles, lips, nipples and portions of
the external genitalia
describe the layers of the hair follicle
- a knot of sensory verve endings called bhiar follicle receptor or root hair plexus wraps around each hair bulb
- bending of hair stimulates these endings helping our hairs to act as sensitive touch receptors
- has a cuticle, medulla and cortex
what is the hair papilla and the hair matrix?
Hair papilla - dermal tissue that protrudes into the hair bulb and has capillaries
Hair matrix - actively dividing area that produces hair, as cells are pushed upward they become increasing keratinized and die
what determines hair colour
- pigment made by melanocytes at the abse of the hair follice
- blonde and red hair have only a small amount of eumelanin, also have pheomelanin
- black hair is all eumelanin
describe the stages of hair growth
- 3 step growth cycle
- Growth stage
- cells of matrix differentiate, keratinize and die
- forms root sheath and shaft
- scale: 2-6 years growth at 0.3mm/day rgowth rate
- Resting stage
- growth of hair stops, can last for 3 months on scalp
- After resting stage
- hair replaces and new growth stage
what is alopecia
- patial or complete hair loss
0 results from genetic factors, aging, endocrine disorders, chemotherapy or skin disease
describe Pattern baldness
- androgenic alopecia
- genetically determines and sex influenced
- delayed action gene that “switches on” in adulthood and changes the response of hair follicles to DHT
Treat with: minoxidil (stim hair growth) and finasteride
what is the structure of a nail
- modification of the epidermis made of hard ketatin
- deeper layers of epidermis extend beneath the nail as nail bed
- as nail cells become heavily keratinized the nail body slides distaly over the nail bed
what are the fucntions of the integumentary system
- Protection
- chemical (low pH, glycolipid waterproofing), physical and mechanical barrier
- Cutaneous sensation
- sens external touch/pain
- Body temp
- reg by: BV constiction to keep warm, dilation to inc sweat gland secretions to cool
- Metabolic functions
- synthesis of vitamin D in dermal blood vessels
- Blood reservoir
- skin blood vessels store up to 5% of the bodys blood volume
- Excretion
- limited amounts of nitrogenous wastes are eliminated from body in sweat
describe aspects of cutaneous sensation of the integumentary system
Cutaneous sensation
- called exoreceptors bc they sense external touch and pain
- merket discs: free nerve endings, caress and clothing
- meissners corpuscles: sense light pressure, heat and pain, rapidly adapting
- pacinian corpuslces: deeper alter to deep pressure bumps
- hair follicle receptor or root hair plexus
what is a carcinoma
Cancer derived from epithelial cells and includes those of the breast, prostate, lung and colon
What is sarcoma
Cancer derived from connective tissue, ormesenchymal cells
what are lymphoma and leukemia
Cancer derived from hematopoietic cells
what is a germ cell tumor
Cancer derived from pluripotent cells
What is a blastoma
cancer derives from embryonic tissue
how does skin cancer develop
- most skin tumors are benign and do not metastasize
- crucial risk factor for nonmelanoma skin cancers is disabling the p53 gene (tumor suppressor gene)
- get one mutation, then two mutations, then 3, becomes invassive, if it gets into blood vessel can go to other areas of the body
what are the 3 major types of skin cancer
- Basal cell carcinoma
- Squamous cell carcinoma
- Melanoma
what is basal cell carcinoma
- Least malignant and most common skin cancer
- Stratum basale cells proliferate and invade the dermis and hypodermis
- Can be cured by surgical excision in 99% of the cases
- Slow growing and do not often metastasize
what is squamous cell carcinoma
Arises from keratinocytes of stratum spinosum
Arise most often on scalp, ears and lower lip
Grows rapidly and metastasizes if not removed
Prognosis is good if treated by radiation therapy or removed surgically
what is melanoma
- cancer of the melanocytes, is the most dangerous type of skin cancer because
- > highly metastatic
- > resistant to chemotherapy
- treated by wide surgical excision and immunotherapy
- chance of survival is poor if lesion is over 4mm thick
what are the characteristics of melanoma
ABCD
- A: Asymmetry; two sides of the pigmented area don’t match
- B: Border is irregular and exhibits indentations
- C: Color is black, brown, tan and sometimes red or blue
- D: Diameter is larger than 6 mm (size of a pencil eraser)
what are burns
- caused by heat, electricity, chemicals, light, radiation or friction
- burns can be highly variable in terms of tissue affected, severity and resultant complication
- muscle, bone blood vessel, dermal and epidermal tissue can all be damaged
- pain is due to inury of nerves
what is a first gree brun
- superficial thickness
- depth: epidermis involvement
cncial findings: erthema, minor pain, lack of blisters
what is second degree burn
- partial thickeness - superfiscial
- depth: superficial (papillary) dermis
- clinical findings: blisters, clear fluid and pain
what is a third degree burn
- partial thickness (deep)
- depth: deep (retiruclar) dermis
- whiter appearance
what is a fourth degree burn
- full thickness
- depth: epidermis, dermis and partial damage to subcutaneous fat, eschar formation and minial pain, requires grafts
what is a fith degree burn
- subdermial
- complete destruction of epidermis, dermis, subcutaneous fat and underlying tissue and possible fascia, bone or mucle
- hard leather like eschar, purple fluid, no sensation (insensate)
when is a burn considered critical
- Over 25% of the body has second-degree burns
- Over 10% of the body has third-degree burns
Third-degree burns on face, hands, or feet
rule of 9s to calculate burn sevarity
legs: 9%
anterior trunk: 18%
arm: 4/12%
head: 4 1/2^
burns can be potentially fatal, describe pathology of first 24 hr after burn
- Hypothermia
- Tissue/blood destruction and hemoglobin loss leadshypoxia
- Glomerular filtration rate and urinary output reduced andmetabolic acidosis
- Plasma loss of proteins 4-6 hours post injury results in reduced intravascular colloid pressure causing plasma fluid loss
