Integumentary Flashcards
Regulates body temperature
* Stores blood
* Protects body from external environment
* Detects cutaneous sensations
* Excretes and absorbs substances
* Synthesizes vitamin D
Integumentary System
Two ways the skin regulates temperature (thermoregulation)
- Liberating sweat at its surface
- Adjusting flow of blood in the dermis
(Blood reservoir) ______ houses an extensive network of blood vessels
* ____ of total blood flow
Dermis, 8-10%
(protection) _____ in the skin protects underlying tissues from microbes, abrasion, heat, and chemicals
Keratin
_____ released by lamellar granules inhibit evaporation of water from the skin surface
Lipids
_____ against damaging UV light
Melanin
_____ is the largest sensory organ
Skin
What type of vitamins does the skin absorb?
Fat soluble vitamins (ADEK)
_____minutes ____ a week is required for Vitamin D synthesis
10-15, 2x
4 principal types of cell in epidermis
- keratinocytes
- Langerhans cells
- melanocytes
- tactile epithelial cells
90% of the epidermal cells arranged in four or five layers and produce the protein ____
keratin
Intraepidermal macrophages
participate in immune
responses
Langerhans cells
8% of the cells and produce the
pigment ____
melanin
Cells responsible for detecting touch sensations
Tactile epithelial cells
5 layers of epidermis (CLGSB)
- Stratum Corneum
- Stratum Lucidum
- Stratum Granulosum
- Stratum Spinosum
- Stratum Basale
- Dead keratinocytes
- Continuously being
shed
Stratum corneum
- Found only in thick skin
- Flattened, clear, dead keratinocytes
Stratum lucidum
Contains keratohyaline
granules
Stratum granulosum
- Thickest sublayer
- Provides strength and flexibility
Stratum spinosum
- Deepest layer
- Single row of cuboidal to low columnar cells
- Produce new keratinocytes
Stratum basale
a. Present in keratinocytes
b. Release a lipid-rich secretion that acts as a water-repellent sealant,
retarding loss of body fluids and entry of foreign materials
Lamellar granules
As the cells move from one epidermal layer to the next, they accumulate more and more keratin, a process called _____.
keratinization
Newly formed cells in the _____ are slowly pushed to the surface.
stratum basale
Deeper part of the skin
* Composed mainly of connective tissue containing collagen and
elastic fibers
Dermis
The superficial part makes up about 1/5 of the thickness
* Thin layer of areolar connective tissue and elastic fibers
* Dermal papillae
* Capillary loops and nerve endings
Dermis: Papillary layer
Thick collagen bundles and some coarse elastic fibers
* Dense irregular connective tissue
* Appendages are found
Dermis: Reticular layer
Striae: a form of internal scarring
Stretch marks
Internal damage to dermis when skin is stretched to much
* Bonding between collagen fibers disrupted, small dermal blood
vessels rupture
* Appear as reddish streaks
* Then as silvery white streaks
* Pregnancy, weight-lifters, obesity
Stretch marks
Downward projections of the epidermis into the dermis
* Create strong bond between epidermis and dermis in areas of high mechanical stress
Epidermal ridges
Increase surface area to increase grip of hand and foot by increasing
friction
* Increase surface area to increase tactile sensitivity
* Contribute to the formation of fingerprints (or footprints)
* Unique for each individual
Epidermal ridges
Increase surface contact between epidermis and dermis
* Extensive network of small blood vessels, important source of nutrition
Dermal Papillae
Epidermis and dermis fit to form extremely strong junction
* Strengthens skin against shearing forces that attempt to separate
these two
Dermal papillae
Produced by melanocytes
* Amount of ____ causes the skin’s color to vary from pale yellow to
reddish-brown to black
* Freckles, age spots
* Albinism, vitiligo
Melanin
Red color; due to oxygen carrying pigment of RBCs
Hemoglobin
Yellow-orange pigment
Carotene
Accessory structures of the skin
Nail, hair
Made up of flattened structures of horny or cornified texture
* Found on dorsal surfaces of the terminal phalanges, fingers and toes
Nail
3 parts of the nail
Nail bed, matrix, lanula
Thin, non-cornified epithelium on which the nail plate lies
Nail bed
Proximal, thicker part of the nail bed
* Responsible for nail growth
Matrix
Near the root of the nail, the nail bed is less vascular and nail not firmly adhered to the connective tissue stratum.
* Portion of a whiter color and called the on account of its shape
Lanula
Present in all parts of the body except
* palms and soles
* dorsal surfaces of the terminal phalanges
* glans penis
* inner surface of the prepuce
* inner surfaces of the labia
Hair
____ develops from the gland-like growth of the epidermis into the dermis which gives rise to the hair follicles.
Hair
Main body of the hair
Hair shaft
Bundles of smooth muscles typically associated with hair follicles
* Erect the usually obliquely lying hair
* Exert pressure upon sebaceous glands, causes the discharge of their
secretion into the hair follicle.
Arrector pili muscles
Contraction of the ______ give rise to bumps on the skin or “goose flesh”
arrector pili muscles
- Decrease in number, stiffen, break apart, and disorganize into a shapeless, matted tangle
Collagen fibers in the dermis
- Lose some of their elasticity, thicken into clumps, and fray, an effect that is greatly accelerated in the skin of smokers
Elastic fibers
- Produce collagen and elastic fibers
- Decrease in number result wrinkles
Fibroblasts
_____ – skin forms characteristic crevices & furrows.
Wrinkles
Most age-related changes begin at about age ___
40
