BIOL 2457 1st Edition Lecture 12Outline of Last Lecture I. DermisOutline of Current LectureI. SKELETAL SYSTEM: Bone Tissue II. Functions: - Bones are attached to our skeletal system, - Movement externally and locomotion is internally. - Support, protect our heart and lungs etc.- Mineral homeostasis, (calcium 99% of body, a-cellular matrix is made up of many protein fibers= give it flexibility) (bone is very malleable) (phosphorus)- Blood cell production is Red marrow (lymphoid tissue=linthocytes, Milothoidtissue=..) produce RBC, WBC and platelets- Triglyceride is made by Yellow marrow, adipose cells III. Structure: - Medulla is the cavity inside the long bone- Complex compact bone (on the outside, strongest and hardest, protection and support) Osteons are the repeating structural units, have the osteocytes in the lacuna- Spongy bone (trabeculae bc of the columns) is more at the bottom, dense. Osteoclasts are readily found in the endosteum and sometimes in the periosteum - Proximal Epiphysis at top of bone Distal Epiphysis at the end of bone- Diaphysis is the middle of the bone- Metaphysis is the between of prox epip and diaphy and diaphy with distal epip- Articular cartilage is what surrounds the top and bottom of bones like a covering - Periosteum lines the outside - Endosteum lines the inside ENDO= INIV. Histology:- Extracellular matrix surrounding widely separated cells Matrix is 25% water, 25% collagen fibers, 50% crystallied mineral salts- Calcification is calcium deposits, happen any place, specific bone mineralization, when that happens calls is os…- 4 types of cellsOsteogenic cells: develop into osteoblastsOsteoblasts: Build boneOsteocytes: mature bone cellsOsteoclast: Macrophage, cleaves bones, melt away, break down regulate calcium salts (calcium is used for blood clotting, don’t have dietary calcium you will lose bone like crazy)V. Blood and Nerve supply:- Veins are blue - Arterys are redVI. Bone formation:- Ossification: process by which bone is formed- 4 SISTUATIONS OF BONECartilage formation and ossified specific type of calcimisfaction o Intramembranous ossification is not as common, flat bones, bc dermalbones grow out of a superficial epithelial layer and underline connective tissue (Flat spot of baby’s head) (Glass and stick clay on the inside) (Patella is a kneecap and is a seasmoid bone bc it grows like a seed) o Endochondral replaces cartilage by bone by ossification, most bones are formed this way (Clay) Ossification center it grows from the inside out. Growth in length, once plate is aligned you don’t get longitudinal growth afterthat. Exposed to way too much growth hormones you can have gigantisim, where you are really long. Dwarfisim Is not having exposure to growth bone. o WOLFF’S LAW says greater the load the thicker the bone (bring inmore matrix to support the load) 7 years takes place for new bone, remodeling. A balance must exist between the actions of osteoclasts and osteoblasts. Osteoporis is excessive loss of calcium, and osteomalacia is when it becomes too flexible Bone remodeling has 2 factors like, o Factors: Minerals and Vitamins (a-activity of osetoblasts, c-syntheisingcollagen ,d-building bone bc cant absorb calcium wo it ,k-syntheisize other
View Full Document
Unlocking...