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29 Cards in this Set

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Define Integument
-the protective, pliable covering over the surface of the body
-The skin is the largest organ in the body
Define Integumentary System
-a body system consisting of the integument and any accessory skin structures, such as nails, hair, and glands
Functions of the Integument:

protection?
-protection from infectious agents
-the integument acts as a physical barrier and has a slightly acidic pH which acts as an antiseptic layer, preventing organisms from entering the body
Functions of the Integument:

perception?
-perception on the environment
-neural receptors of the skin
Functions of the Integument:

prevention?
-prevention of drying out and absorption of water (keratin)
Functions of the Integument:

regulation?
-a coordinated activity of nerve endings, blood vessels, and sweat glands
Functions of the Integument:

secretion?
-production of sebum by the sebaceous glands
Functions of the Integument:

excretion?
-release of urea and NaCl by the sweat glands
Functions of the Integument:

production of?
-production of Vitamin D
Functions of the Integument:

emotions
-allows for emotions
-ex: blushing, smiling, frowning
Epidermis

How is the epidermis affected by tanning?
-UV light stimulates melanocytes to produce melanin which is then picked up (phagocytized) by more superficial cells of the epidermis
Epidermis

What are freckles?
-localized collections of melanin
Epidermis Cell Types

Keratinocyte
-primary cell type of the epidermis (arise from mitotically active cells called basal cells)
-generates keratin
Epidermis Cell Type

Melanocyte
-a cell of the germainativism layer of the epidermis
-produces melanin, a black pigment of the skin
Epidermis Cell Type

Langerhans cells
-Langerhans cells are Nonpigmented granular dendrocytes
-they arise in bone marrow and reside in the spinosum layer of the epidermis
-sensitive to UV radiation
-present antigens to T cells to assist the immune response
Epidermis Cell Type

Granstein cells
-Granstein cells are Nonpigmented granular dendrocytes
-resistant to UV radiation
-interact with suppressor T cells to assist the immune response
Epidermis Cell Type

Merkel cells
-mechanoreceptors of the germinativum layer of the epidermis (found in areas where hair is lacking; release chemicals that stimulate sensory nerve endings)
Layers of the Epidermis

stratum germinativum or stratum basale
-the inner, mitoically active cell layer of columnar to cuboid shapes cells
-the cells contain melanin produced by melanocytes
-cells are joined by desmosomes
Layers of the Epidermis

stratum spinosum
-a region several cell layers thick; deep cells are polyhedral, superficial cells are flat
-cells are characterized by cytoplasmic spines which meet from other cells at a desmosome (spines maitain cohesion between cells and thus, resist abrasion)
Layers of the Epidermis

stratum granulosum
-granulosum=granular
-a region of 3-5 layers of flattened cells whose cytoplasm contains keratohyalin granules; keratohyalin is a protein which will form eleidin
-nuclei are degrading; outermost cells are dead
-extruded materials from these cells offer a barrier to foreign materials and water
Epidermis Description:

What is carotene?
-carotene is a yellow pigment which can be convertd to Vitamin A
Epidermis Description:

What about Albinos?
-Albinos have melanocytes but lack the enzyme neccessary to convert tryosin to melanin.
*Asians have an abudance of carotene
Epidermis Description:

layer?
-outer, thinner layer of skin
Epidermis Description:

kind of epithelium?
-consists of stratified squamous epithelium
-a derivative of the ectoderm
Epidermis Description:

colored?
-the epidermis is colored because of the presence of melanin, carotene, and blood
Epidermis Description:

What is melanin?
-produced by melanocytes of the epidermis; specifically an enzyme called tyrosinase coverts tryosine to melanin
Layers of the Epidermis:

stratum lucidum
-lucid=clear
-a clear, homogenous layer composed of flattened, drying cells which contain eleidin
-this layer is 3-5 cells thick
-cell boundaries and nuclei are rarely seen
Layers of the Epidermis:

stratum corneum
-cornu=horn
-the outermost epidermal layer, consisting of flat, scale-like, dead, cornified cells whose cytoplasm contains the fibrous protein keratin.
-this surface is water-resistant, not waterproof. Interstital fluid slowly penetrates the surface to be evaporated into the air. This is different from lost by perspiration.
-cells of the corneum are held together by modified desmosomes
-the stratum corneum forms a barrier against light, heat, bacteria, and chemicals
-it takes about 2 weeks to 1 month for cells to arise by mitosis in the germanativum layer, push to the surface of the skin, and slough off
Layers of the Epidermis:

What is keratin?
-Keratin arises from eleidin and waterproofs the skin