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What are the 6 functions of the skeletal system & briefly describe each one
- support- structural framework, attachment for tendons & ligaments
- protection- protects internal organs
- movement- assist in movement
- mineral homeostasis- keep blood calcium & phosphate w/in normal limits by storing & releasing these minerals
- hematopoesis- production of blood cells in red bone marrow
- fat (energy) storage- triglycerides stored in yellow bone marrow
what are the 4 cellular components of BONE TISSUE?
- osteogenic cell- precursor to other cell types (bone stem cell)
- osteoblast- forms bone extracellular matrix (bone building)
- osteocyte- maintains bone tissue
- osteoclast- breaks down bone (bone chewing)
what are the 2 extracellular components of BONE TISSUE?
- HYDROXYAPATITE- mostly inorganic portion of bone (cellular matrix), mineral, compound of calcium, phosphate, & hydroxyl goups- Ca10(PO4)6(OH)2
- COLLAGEN- mostly organic portion of bone, collagen type 1, many minor proteins
- *MINERAL & ORGANIC components need to work together
- -mineral alone is too BRITTLE
- -organic alone is too FLEXIBLE
what comes about when there is TOO MUCH mineral in the bone?
osteogenesis imperfecta- "brittle bone disease"
what comes about when there is TOO MUCH collagen in the bone?
- bones are soft & pliable causing:
- -rickets in children
- -osteomalacia in adults
describe COMPACT BONE
- gives bone its strength
- hard, dense tissue that provides structural support
- basic structural unit- osteon (how they grow, form, remodel)
- each osteon consists of series of concentric rings called lamellae, in the center of the structure is a canal (central canal or haversian canal) that runs the length of the bone, carries blood & lymphatic vessels
- small spaces (depressions) called lacunae, between the lamellae contain the osteocytes
- small channels, called canaliculi, join adjacent lacunae
- perforating canals, or volkmann canals, run radially in long bones to join adjacent central canals
describe SPONGY BONE
- found in marrow cavity (formed from spongy bone) of long bones (femur & humerus)
- made up of trabeculae (doesn't have an osteon)
- osteocytes lie in open spaces lacunae
- canaliculi link the lacunae (communication canals)
- osteoclasts & osteoblasts lie along surface of each trabecula
- several loosely organized rings
spiky projections formed from several loosely organized layers (in spongy bone)
describe what the MARROW CAVITY does in spongy bone
- red bone marrow- blood cells are made (hematopoiesis)
- yellow bone marrow- storage of energy as fat
process where blood cells are born (in red bone marrow)
what are the 3 types of CARTILAGE?
- hyaline cartilage- "glassy" resemblance: shiny & translucent- cartilage lining joints & forming much of nose, ribs
- fibrocartilage- fibrous in appearance & structure- in intervertebral discs, pubic symphysis & meniscus of joints
- elastic cartilage- similar, but has elastin fibers in place of collagen fibers found in fibrocartilage- in ear & epiglottis (structures that need to be flexible & snap back into shape)
describe DENSE REGULAR connective tissue in the skeletal system
- found in ligaments (joins bone to bone) & tendons (joins muscle to bone)
- there is a striated appearance due to oriented collagen fibers
explain DENSE IRREGULAR connective tissue in the skeletal system
- periosteum- dense irregular connective tissue (thin memebrane) that surrounds bone
- rich blood supply
- participates in bone repair
- nerves- pain
- is NOT located on articulating surfaces!!
- it connects ligaments & tendons to bones