intro to physio

• areolar 
• adipose
• reticular

• cushions organs; provides support but permits independent movement; phagocytic cells provide defense against pathogens
• beneath dermis of skin, digestive tract, respiratory and urinary tracts
• most diverse of connective tissue

• provides padding and cushions shocks, insulates (reduces heat loss); stores energy
• deep to the skin at skides, buttocks, breasts

• provides supporting framework
• liver, kidney, spleen, lymph nodes and bone marrow
• uniform consistency

• regular (provides firm attachment; conducts pull of muscles; reduces friction between muscles, stabilizes relative positions of bones; located between skeletal muscles and skeleton 
• irregular (provides strength to resist forces applied from many directions; helps prevent overexpansion of organs such as urinary bladder) anti-parallel

tendon connect muscle and bone; ligaments connect bone and bone

cartilage and bone

• consists of a matrix of firm gel ground substance surrounding embedded fibers
• cells within the matrix (chondrocytes) are found in small pockets (lacunae)

a perichondrium which contains an outer, givrous layer (for strength) and an inner, celular layer (for growth and maintenance)

• hyaline
• elastic
• fibrocartilage

provides stiff but somewhat flexible support, reduces friction between bony surfaces

cells within the matrix of firm gel ground substance (cartilages)

small pockets where chondrocytes are found

provides suppport but tolerates distortion without damage and returns to original position; auricle of external ear

• resists compression; prevents bone to bone contact; limits movment
• pads wihin knee joint, between pubic bones of pelvis and intervertebral discs

osseous tissue has a matrix composed o hard calcium componds (strong) and flexible collagen fibers (resists shattering) with virtually no ground substance

small channels through bone matrix access blood supply

osteocytes are arranged in lacunae around central canals within matrix

composed of skin (cutaneous membrane with 2 epithelial layers) and accessory structures

located deep into the dermis; hypodermis is not part of skin just keeps the epithermis attached to the connective tissues beneath

• protection: prevents fluid loss and covers underlying tissues (water proof)
• temperature maintenance: skin regulates heat exchange with the environment
• synthesis and storage of nutrients: epidermis synthesizes vitamin D3. dermis stores lipids in adipose tissue
• sensory reception
• exretion and secretion

stratified

• surface
• stratum corneum (very thick)
• stratum lucidum
• stratum granulosum (in feet and palms)
• stratum spinosum
• stratum basale
• basement membrane
• dermis

• single layer of cells attached to basement membrane by hemidesmosomes
• forms epidermal ridges down into dermis (dermis has dermal papillae up into epidermis)

• given that the epidermis is avascular, epidermal ridges and dermal papillae is needed to transfer nutrients 
• increase in ridges and papillae increase nutrient uptake b/c of the increase in surface area

the result of stem cell division

cells make a lot of keratin (a protein that provides water resistence and the foundation for hair and nails)

densely packed into a highly keratinized layer

contains 15-30 layers of keratinized or cornified dead cells connected via desmosomes (therefore shed in large groups)

• derived from choleserol-related steroid in the epidermis when exposed to sunlight
• vitamin D is modified by liver and kidneys into calcitriol, essential for calcium and phosphorus absorption in the small intestine
• increases Ca+2 reabsorption by kidney
• promotes calcium deposition in bone

• carotene: accumulates in epidermis
• melanin produced by melanocytes near stratus basales cells, absorbs UV to protect deeper layers

UVB promotes 90%of our vitamin D synthesis while UVA goes deeper and can cause Folic Acid (vitamin B9) breakdown

• basal cell carcinoma: in stratum basale
• squamous cell carcinoma: found in more superficial layers
• malignant melanoma: begins with mole and can metacize thorugh lymphatic system

• papillary: contains capillaries and nerves supplying the epidermis
• reticular: interwoven meshwork of dense, irregular connective tissue (elastic and collagen). Collagen fibers extend from up into the dermal papillae down into hypodermis

• aka subcutaneous layer
• stabilize skin to underlying tissues
• made of areolar tissue and many adipose cells
• no vital organs in area to make it ideal site for subcutaneous injections

epithelium at the base of follicle caps over it

epithelial stem cells divide

epidermal layers invaginate into the dermis

• secrete oily sebum into hair follicle
• holocrine (whole cell breaks down)

• secrete sebum directly into skin of face, back, chest, nipples
• sebaceous glands are sensitvie to hormonal changes

• apocrine
• merocrine

• become active at puberty and secrete sticky, cloudy sweat into hari follicles in armpits
• thought to function as olfactory pheromones

• coiled tubular structures that secrete watery perspiration directly onto surface of skin
• sweat contains electrolytes, urea and organic nutrients
• function is to cool body through evaporation