Integumentary System-Anatomy 

==Skin== is the largest organ in the body.

==Thick skin== - palmar and plantar

==Thin skin== - eyelids

==Main function of skin== - synthesize vitamin D

==Epidermis== - keratinized stratified squamous

==Dermis== - dense fibrous irregular (collagen)

==Hypodermis== - adipose and areolar tissue

==Epidermal cell types== - keratinocytes, melanocytes, Langerhans cells

==Keratinocytes== - tough keratin (90% of cells)

==Melanocytes== - skin color; filter UV rays

==Langerhans Cells== - skin immunity

==Stratum Corneum== - most superficial; desmosomes

==Hyperkeratosis== - callous’

==Stratum Lucidum== - absent in thin skin; ELEIDEN (soft gel; makes fingertips puffy)

==Stratum Granulosum== - degeneration; keratinization begins

==Stratum Spinosum== - rich in RNA

==Stratum Basale== - mitosis

==Stratum Germinativum== - growth

==Regeneration of epidermis== takes 35 days; process can be sped up by scraping

==Blisters== - destruction of epidermal desmosomes

==Dermis== - thicker than the epidermis

==Main functions of dermis== - hair follicles, sweat glands, sebaceous glands, and blood vessels

==Layers of dermis== - Papillary and Reticular

==Papillary== - fingerprints; GRIPPING

==Reticular== - goosebump layer/muscle

==Fibroblast== - build fiber

==Keloid== - thickened scar

Most common skin cancer is ==malignant melanoma==

==UV radiation== - damages DNA → mitotic division → cancer

==Skin color== - melanocytes; tyrosinase converts into melanin

==Pale skin== - constriction of blood vessels

==Blush skin== - dilation of blood vessels

==Cyanosis== - bluish skin

==Vitiligo== - pigmentation missing in patches

==Surface film== - residue from sweat glands; blocks toxins/antibacterial

==Langer lines== - surgery lines

==Hypothalamus== - regulates body temperature

Heat produced by the metabolism of food (==calories==)

==Lanugo hair== - covers fetus but sheds before birth; common in premature babies

Hair grows about ==1/2 inch== per month

==Germinal matrix== - growth point for hair and nails

==Lunula== - white at the base of nail

==Sweat gland== - sudiferous gland

==Eccrine== - sweat glands

==Apocrine== - smell & bacteria glands

==Bacteria== - strep, staph, impetigo, boils

==Virus== - warts

==Fungal== - tinea

==Tinea pedis== - athletes foot

==Tinea corporis== - ringworm

==Tinea cruris== - jock itch

==Articulations== - joints

==Long bone== - femur and humerus

==Short bone== - phalanges

==Flat bone== - cranium, sternum, scapula

==Irregular== - vertebrae, pelvis

==Seismoid== - patella

==Diaphysis== - shaft of long bone

==Epiphysis== - ends of long bone (bone marrow)

==Endosteum== - lining of medullary cavity

==Epiphyseal plate== - growth plate

==Articular cartilage== - hyaline at joints

==Periosteum== - covers the long bone

==Medullary cavity== - hollow space in diaphysis

==Compact bone== - osteons (haversian canals) - run lengthwise to deliver and remove

==Lamella== - concentric, calcified layers

==Lacunae== - fluid and osteocytes

==Canaliculi== - ultra small canals connecting lacunae to haversian, blood and lymph

==Volkmann’s canal== - transverse to exterior surface

==Cancellous bone== - areas of increased strength (epiphysis)

==Osteocyte== - mature bone cells

==Osteoblast== - build bone

==Osteoclasts== - break down bone

==Osteogenic cells== - stem cells

==Bone marrow== - myeloid tissue; RBC production

Bones store ==98%== of body’s calcium

Osteoblast ==remove calcium== from blood to build bone

Osteoclast ==release calcium== into blood

==Calcium== is needed for skeletal and cardiac muscle contraction, nerve impulses, and blood clotting

==Osteogenesis== - creation of bone

==Intramembranous ossification== - form bones from membranes

==Appositional growth== - layering of osseous tissue to outer surface

==Endochondral== - bone forms from cartilage



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