MarkeciaBogard20

General Function of Integumentary System and Hypodermis

Components of the Integumentary System (consist of skin and its appendages.

Layers of the Epidermis and special features and functions.

Cell types located in Epidermis

Epidermis:Composed of 4 types of cells keratinocytes, melanocytes, tactile epithelial cells and dendritic cells.

Dermis : .Well supplied with blood vessels and nerves. 20% of Papillary layer and 80% of Reticular layer

Hair Shaft: The part that is superficial to the skin.

Hypodermis or Superficial fascia: underlies the skin, primarly composed of adipose tissue.

Nervous Structures: Sensory nerve,Lamellar corpuscle, Hair follice receptor

Appendages of skin: Eccrine sweat gland, arrector pili muscle, sebaceous gland, hair root, hair follicle

Subpapillary vaascular plexus

Dermal vascular plexus

Dermal papillae: A knot of capillaries that deliver sunstances that will stimulate and supply nutrients to grow hair.

Sweat pore

Production of vitamin D: Use UV radiation to synthesize vitamin D. Vitamin D is need for absorbing calcium.

Sensory Receptors: Associated with the nerve endings. These receptors keep us aware of conditions on the body surface, Such as, touch, pressure,tempertaure and pain.

Temperature Regulation: Sweat glands and blood vessels help keep thermal regulation throughout the body

Excretion: Helps to excrete urea, salts and water through sweat

Protection: from external harm, including UV radiation

Hypodermis Function: Mostly adipose tissue. Usage of Nutrients storage, insulation, and cushioning

Dendritic Cells: Known to take a pathogen to the lymph nodes to eventually get destroy it.

Tactile epithelial cells (Merkel cells): Receptor cells that are sensitive to touch.

Melanocytes: Create the pigment melanin and helps protects against harmful UV radiation

Stem Cells: Creates more keratinocytes.

Keratinocytes: Contains tough fibrous protein called keratin and connect together with special contacts called desmosomes.

Stratum Granulosum

Stratum Spinosum

Stratum Lucidum

Stratum Basale:

Stratum Corneum

Mostly stem cells present

Basal Layer of cells/ Deepest layer of epidermid

Thick and protective

Th spines of the desmosomes hang onto each other.

Mostly Keratinocytes

Protective

Helps prevent loss of water

1 to 5 layers of flattened keratinocyers cells are present

Special contact epithelial cells called tight junctions are present.

Protective

Some keratinocytes are present.

Only in located thick skins such as palms and soles of feet.

Superficial layer of epidermis

Protective

Several layer of dead keratinocytes

Mostly stem cells present

10% - 25% of cells are melanocytes

Glycolipids in extracelluar matrix

Sweat glands helps to prevent the body from overheating.

Hair root is embedded into the skin within follice.

Hair follicles extend from the epidermal surface into the dermis.

Arrector pili muscle is a smooth muscle that relax and erect the hair. (muscle that controls hair raising when a person gets goosebumps.

Sebaceous Glands

Nail

Function: Protects fingertips and toe tips

Structure: Dead cells filled with keratin

Apocrine sweat glands

Exocrine sweat glannds:

Function is evaporative cooling

Located nearly everywhere

Mercocrine secretion allows the cell to just realease the product such as watery sweat and some salts.

Located in axillary region, anal and genital areas.

Function is odor producing. Bacteria decomposes the proteins and lipids to create the odor.

Apocrine secretion allows the cells to secrete a portion of the apical cells that includes proteins and lipids.

Located everywhere except palms of hands and soles of feet. Also associated with hair

Function is to produce an oil and collect dirt