Lecture Exam 2 Study Guide 3/17/16 10:47 PM

What is endochondral ossification?

Bones

• Support, protection, movement, mineral and growth factor storage, blood cell  formation, fat storage, and hormone production

• Osteoblasts are bone building cells; they secrete unmineralized bone matrix called  osteoid

• Osteoclasts are bone breaking cells; they are huge, multinucleate cells that engage in  bone resorption

• Calcium Phosphate, Calcium Hydroxide, and Calcium Carbonate; First calcium  phosphate and calcium hydroxide combine to create hydroxyapatite. This further  combines with calcium carbonate and other ions to form mineral salt deposits that  harden into bones in a process called calcification

• Red bone marrow is found primarily in flat bones and is responsible for producing  red blood cells, white blood cells, and platelets

What is elastic cartilage?

• Yellow bone marrow is located in the shaft of long bones and is responsible for  producing fat, cartilage, and bone

• Collagen fibers in the osteons run in different directions in adjacent rings which  helps bones withstand stress and resist twisting

• Collagen in the bone combines with minerals to form hydroxyapatite to form the  structure, flexibility, and strength of bones

• Osteocytes respond to mechanical stimuli and communicate the information to  osteoblasts and osteoclasts so bone remodeling can occur We also discuss several other topics like What is behavioral and cognitive psychology?

• Hyaline Cartilage: joints, connecting ribs to sternum, larynx, nose tip

• Fibrocartilage: pubic symphasis, vertebral discs, menisci of knees

• Elastic Cartilage: external ears and epiglottis

What is the use of bones in our body?

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• Ossification is the process of laying down new bone material by osteoblasts while  calcification is the mineralization and hardening of already existing bone tissue • Scenario 1: Embryonic Formation of Bony Skeleton - hyaline cartilage and fibrous  membranes of fetal skeleton are replaced with bone tissue; comes from  We also discuss several other topics like What are the components of aggregate expenditures?

mesenchyme; endochondral and intramembranous ossification

• Scenario 2: Postnatal Bone Growth – long bones grow by way of epiphyseal plate  growth; bones increase in thickness because of appositional growth; this process  stops after adolescence

• Scenario 3: Bone Remodeling – a small percentage of bone tissue is being replaced  at any time; new bone is stronger; process includes resorption and deposition • Scenario 4: Bone Repair – reactive, first reparative, second reparative, and  remodeling stages to fix broken and fractured bones

• Endochondral Ossification: Bone collar forms around diaphysis of cartilage model;  central chondrites in diaphysis calcifies, then they go through apoptosis, resulting in  cavities; periosteal bus invades cavities forming spongy bone; diaphysis elongates  and the medullary cavity forms; epiphyses ossifies

• Intramembranous Ossification: Mesenchymal cells cluster and become osteoblasts  in ossification centers; osteoid is secretes, then calcifies; osteoid is laid down around  blood vessels forming trabeculae; the lamellar bone replaces the woven bone

• Resorption: the process of minerals from bones being returned to the blood • Resorption Process: osteoclasts dig grooves in bones called resoption bays; secrete  enzymes and proteins that digest the matrix and increases acidity to break down the  calcium salts and the organic parts of the matrix; digested fluids are trancysoed an  released into the blood; osteoclasts apoptose If you want to learn more check out What is machiavelli most famous for?
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• Deposition: the process of new bone being laid down

• Bone Repair: Reactive stage – fracture hematoma; First reparative stage – fibrocartilaginous callus; Second reparative stage – bony callus; Remodeling stage – osteoclasts resorb last bits of fractured bone

• Zones of Growing Epiphyseal Plate: Resting Zone – cartilage on the epiphyseal side  of epiphyseal plate that is fairly inactive; Proliferation Zone – cartilage on diaphysis  side of epiphyseal plate whose cells rapidly divides and move upward causing  lengthening; Hypertrophic Zone – cartilage lacunae grow and erode causing the  formation of interconnecting spaces; Calcification Zone – Surrounding cartilage  matrix calcifies and chondrocytes die and deteriorate; Ossification Zone – the  deterioration of chondrocytes creates long spicules of calcified cartilage at  epiphysis-diaphysis junction that are then eroded and covered with new bone by  osteoblasts. Afterwards, this new bone is replaced with spongy bone until the  medullary cavity enlarges and the spicules are eroded

3/17/16 10:47 PM

3/17/16 10:47 PM