Integumentary System By Nicole Hennen Sec. 31

Components:

Hair

Nails

Skin

considered an organ due to having more than 1 tissue type. Contains all 4 tissues types

composed of dead cells filled with hard keratin

composed of hard keratin

General Functions including hypodermis

Protection

temperature regulation

excretion

production of vitamin D

sensory reception

Exocrine Glands

sweat gland (two types, eccrine and apocrine) and sebaceous glands(produce oil)

minor role: eliminates water & electrolytes; wastes

waterproof barrier from outer elements (water, dirt, UV radiation)

thermoregulation- blood vessels & sweat glands assist in lower or rising body temp.

produced with help of UV radiation. Is needed to help body absorb calcium for strong bones and teeth

Hypodermis made primarily of adipose; provides insulation(fat storage), connection to deeper tissue(loose connection to muscle)

Cells of the epidermis

Keratinocytes

Stem cells

Melanocytes

Tactile epithelial cells (Merkel cell)

Dendritic cells

cells have abundant keratin (tough protein) from basal layer all the way to apical layer

located in the stratum basale; make new cells pushing up the dead cells.

sensory receptor, sensitive to touch

pigment producing cells; produce melanin, more melanin=darker skin

member of the immune system; mobile, stretches between cells in stratum spinosum. (patrols to keep harm out)

Layers of epidermis

Stratum basale

Stratum spinosum

Stratum granulosum

Stratum lucidum

Stratum corneum

dead cells; losing most of their organelles, filled with keratin

Stem cells are abundant, melanocytes and tactile epithelial cells found in this layer

flat layer of keratinocytes; present in thick skin

granules that produce a water proofing glycolipid that secrets from the cell

5-20 layers thick, superior to stratum basale. Cells have "spines" from fibers connected to desmosomes. Dendritic cells wander through.