BIO 240 1st Edition Lecture 12 Outline of Last Lecture II Appendicular Skeleton III Bones of the Upper Appendages IV Bones of the Lower Appendages Outline of Current Lecture I Skeletal System A Functions B 4 Main cell types C Bone Tissue D Bone Morphology Current Lecture I Skeletal System A Functions 1 Protection 2 Support 3 Movement 4 Mineral storage 5 Hematopoietic Blood production Is a major characteristic of spongy bone 6 Energy storage B 4 main cell types These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute 1 Osteoprogenitors stem cells of the skeleton unipotent first bone makers Are mitotic and give rise to osteoblasts 2 Osteoblasts Nonmitotic and secrete the bone matrix calcium and phosphorous salts 3 Osteocytes Nonmitotic mature osteoblasts that no longer secrete the matrix and do regular cell functions Are the brains of bones 4 Osteoclasts Cells that break down bone to access and release minerals Ex Calcium Pregnant women loose a lot of bone density when they re pregnant because the fetus uses so much calcium White blood cells give rise to osteoclasts specifically monocytes Secrete enzymes and acids The enzymes break down proteins and the acids dissolve calcium salts and release them to the blood stream Osteoclasts help to shape and form osteons and trabeculae C Bone Tissue 1 Osteon a 35 of compact bone is Collagen Gives bone flexibility and tensile strength b 65 is calcium salts They have the ability to mineralize and osteosize harden the bone Function for strength against compression c Bone is strong without being brittle d Bone is as strong as steel against compression e Bone is equal to steel in tensile strength f Osteoporosis A condition of bones loosing collagen and osteoblasts being less functional leading to brittle bones Is typical of age Calcium helps with this disease because since osteoblasts are laying down calcium salts taking a supplement replaces their function when they stop working 2 Trabeculae Fundamental unit of spongy bone they form spicules This leaves many porous spaces which are great spots for blood vessels to go D Bone Morphology 1 Flat bones Include all of the skull bones sternum scapula and ribs Is mostly spongy bone internally with a thin sheath of compact bone making up the outside 2 Short bones Include the wrist bones carpals ankle bones tarsals and the patella Cube shaped are about as wide as they are tall There is a greater compilation of compact bone with less spongy bone on the inside making them a little bit stronger 3 Long bones Include the femur tibia Humerus radius ulna metacarpals and metatarsals 4 Irregular bones Include the coxal bones and vertebrae
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