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131 Cards in this Set
- Front
- Back
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What does the skeletal system include? |
Bones of the skeleton, cartilage, ligaments, and other connective tissue that stabilize or interconnect the bones. |
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What are the skeletal system functions? |
Support, storage of minerals and lipids, blood cell production, protection, and Leverage. |
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How does the skeletal system support? |
It's structurally support's the entire body. It provides the framework for the attachment of soft tissues and organs. |
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How does the skeletal system store minerals and lipids? |
the body needs high concentrations of calcium and phosphate ions. So, bone store these valuable minerals and lipids are stored in yellow bone marrow. |
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Where does the skeletal system store and produce blood cells? |
In red bone marrow where red blood cells, leukocytes, and other blood elements are produced. |
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How does the skeletal system protect? |
Skeletal structures like the ribs, pelvis, vertebrae, and skull protect vital organs and soft tissues from damage. |
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How do bones function as levers? |
They change the magnitude and direction of the force generated by the muscle system. |
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In an adult skeleton, how many bones are there? |
Approximately 206 bones |
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What are the six shape categories of Bones? |
1. Sutural bones 2. Irregular bones 3. Short bones 4. Flat bones 5. Long bones 6. Sesamoid bones |
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What are sutural bones? |
Are small, flat, oddly-shaped bones found between the flat bones of the skull. They range in size. |
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What are irregular bones? |
Have complex shapes with short, flat, notched or rigid surfaces like the vertebrae, pelvis, and some skull bones. |
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What are short bones? |
Box-like shaped. For example, carpal bones |
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What are flat bones? |
thin parallel surfaces. For example, roof of skull, sternum, ribs, and scapula. They provide protection and offer extensive surfaces for muscle attachment. |
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What are long bones? |
Long and slender. For example, femur, humerus, ulna, radius, tibia, fibula, metatarsals, metacarpals, and phalanx |
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What are sesamoid bones? |
Small round and flat. Found near joints of knees, hands, and feet. For example, the patella. |
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What are some types of bone markings? |
Projections, openings, and depressions. |
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On a long bone Where is the diaphysis? |
Center of bone between the metaphysis's |
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On a long bone Where is the metaphysis? |
Between each epiphysis and the diaphysis |
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On a long bone Where is the epiphysis? |
At the end. After the metaphysis |
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The diaphysis consists of two layers what are they? |
Compact bone and medullary cavity |
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The epiphysis consists largely of? |
Spongy bone |
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What is present in bone? |
66% of hydroxyapatite 31% of collagen fibers 2% bone cells |
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What are the four types of cells found in bones? |
1. Osteocytes 2. Osteoblast 3. Osteoprogenitor cells (osteogenic cells) 4. Osteoclast |
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What are the two membranes in Bones? |
Periosteum (outer surface of bone) Endosteum (inner surface of bone) |
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What are the two layers of periosteum? |
Outer fibrous layer an inner cellular layer |
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What does the outer fibrous layer in the periosteum provide? |
Confluent with joints and tendons |
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What does the inner cellular layer of periosteum consist of? |
Osteoprogenitor cells |
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What type of cell is osteoprogenitor cells? |
Mesenchymal cells (stem cells) |
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What does osteoprogenitor cells do for bone? |
They divided into daughter cells that differentiate into osteoblasts. |
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Where are osteoprogenitor cells found? |
The inner layer of the periosteum and the cellular layer of endosteum |
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What are |
Are the daughter cells of osteoprogenitor cells that develop into osteocytes |
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What do osteoblasts do? |
Produce new bone matrix in a process called osteogenesis (ossification) by making and releasing in a organic Matrix called osteoid |
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What is osteoid? |
Proteins and other organic components |
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What are osteocytes? |
Mature bone cells. For example, osteoblasts that have been surrounded by osteoid that was converted to bone. |
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Where are osteocytes located? |
In a Lacunae |
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How does osteocytes communicate with other cells? |
Through narrow passageways called canaliculi with gap Junctions connecting each cell. |
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What are the two major functions of osteocytes? |
1. Maintain the protein and mineral content of the surrounding content. 2. Take part in repair or damage of bone. |
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How does osteocytes maintain the protein and mineral content of the surrounding Matrix? |
they secrete chemicals that dissolve the adjacent Matrix and the minerals released enter the blood circulation. Then they rebuild the matrix by stimulating the disposition of new hydroxyapatite Crystal's. |
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Is bone matrix continually turned over? |
Yes |
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How does osteocytes take part in the repair of damaged bones? |
Osteocytes can return to osteoblast or osteoprogenitor cells when released from Lacunae which assist in bone repair |
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What do osteoclast do? |
Absorb and remove bone matrix through osteolysis. |
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What is a special characteristic of osteoclast? |
They have 50 or more nuclei |
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What derivative are osteoclasts from? |
Monocytes and macrophages |
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What do osteoclasts secrete to remove bone matrix? |
Acids and protein digesting enzymes |
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What is the basic functional unit of compact bone? |
Osteon |
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What does the osteon surround? |
Central canal |
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What does the central Canal contain |
Blood vessels |
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What direction do central canals run? |
Parallel to the surface of the bone |
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What is the name of the canal that runs perpendicular to the surface of the bone? |
Perforating canal |
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Where do Perforating canal Supply blood to? |
Osteons deeper in the bone and to tissue in the medullary cavity |
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What are the bone matrix layers called? |
Lamellae |
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What are the lamellae called that form a Target like pattern around the central canal? |
Concentric lamellae |
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What are the male that fill in the spaces between the osteon/concentric lamellae? |
Interstitial lamellae |
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What are the lamellae that line the outer and inner surfaces of bone called? |
Circumferential lamellae |
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Compact bone is thickest where? |
Stressed areas applied from a limited number of directions |
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How can a long bone break? |
When force is applied perpendicular to the Bone |
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What is a trabeculae? |
Lamellae not arranged in an osteon |
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What do you find in spongy bone? |
A network of trabeculae |
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Is there a blood supply to spongy bone? |
Yes, but not in vesicles instead it contains red bone marrow. |
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Where is blood cells formed? |
Red bone marrow |
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Spongy bone can contain what two types of bone marrow? |
Red and yellow |
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Why is yellow bone marrow important? |
Adipose tissue important as an energy Reserve |
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What are the functions of periosteum? |
1. Isolates the bone from surrounding tissue. 2. Provides route for blood vessels and nerves. 3. Takes part in bone growth and repair. 4. Attachment point for ligaments and tendons. |
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What is the function of endosteum? |
Role in growth, repair, and remodeling of bone |
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Where does endosteum line? |
Trabeculae and Central canals |
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Ossification or osteogenesis refers to? |
The formation of bone |
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Calcification is? |
The disposition of calcium salts. Which, takes place in ossification |
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What are the two ways ossification occurs? |
Endochondral ossification and intramembranous ossification |
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What is endochondral ossification? |
Where bones replace existing cartilage |
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What are the two ways endochondral ossification can grow? |
Interstitial growth (length) and appositional growth (width) |
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What is intramembranous ossification? |
Bone develops directly from mesenchyme (Loosely organized embryonic connective tissue) or fibrous connective tissue. |
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When does the skeleton begin to form? |
6 weeks after conception |
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When do bones stop growing? |
About 25 years old |
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What two types of connective tissue do bones develop from? |
Dense connective tissue and hyaline cartilage |
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Interstitial growth means? |
Bones grow in length |
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Appositional growth means? |
Bones grow in width |
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Beginning of ossification in developing bones Step 1 |
hyaline cartilage enlarges. Chondrocytes near the center increase in size. Highland Matrix is reduced to a series of small struts. The struts become calcified. The chondrocytes die leaving cavities within the cartilage. |
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Beginning of ossification in developing bone Step 2 |
blood vessels grow around the cartilage. Cells around the perichondrium convert to osteoblast. Bone begins to form around the shaft of the cartilage. Periosteum is formed from perichondrium. |
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Beginning of ossification in developing bone step 3 |
blood vessels penetrate the cartilage and invade the center. Fiberglass move with the blood vessels changing into osteoblast. Osteoblasts begin to form spongy bone at the center of the bone. Formation then spreads along the shaft. |
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Beginning of ossification in a developing bone step 4 |
Remodeling occurs as growth continues. Medullary cavity is formed. Shaft becomes thicker. The diaphysis is now bone |
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The length of developing bone endochondral ossification Step 1 |
Capillaries and osteoblast move into the epiphysis creating a secondary ossification Center |
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The length of developing bone endochondral ossification Step 2 |
The epiphysis eventually becomes spongy bone. The epiphyseal cartilage separates the epiphysis and the diaphysis. Osteoblast continue to work on the diaphysis side while chondrocytes continue to lay more cartilage down on the epiphysis side of the epiphyseal cartilage. |
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The length of developing bone endochondral ossification step 3 |
At puberty the rate of epiphyseal cartilage slows down and the rate of osteoblast activity increases. The epiphyseal cartilage grows thinner and thinner until complete and left with an epiphyseal line. |
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Intramembranous ossification step one |
mesenchymal cells cluster together, turning into osteoblasts. Osteoblast then secrete osteoid. Osteoid calcifies forming bone matrix. |
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Intramembranous ossification Step 2 |
Ossification continues trapping osteoblast. Osteoblasts then change into osteocytes. Developing bone grows outward in a small struts called spicules |
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Intramembranous ossification step 3 |
blood vessels Branch within the region and grow in between the spicules. Bone growth speeds up with the supply of blood. |
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Intramembranous ossification step 4 |
Continue change by osteoblast close to blood vessels creates spongy bone with blood vessels weeding throughout. |
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Intramembranous ossification step five |
sufficient remodeling around blood vessels produces osteons in compact bone. Osteoblast on surface of bone and connective tissue become periosteum |
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In order for bone to grow and be maintained it requires what |
Blood |
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Is osseous tissue avascular? |
Yes |
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What is the nutrient artery and vein? |
Blood vessels that supply the diocese form by invading the cartilage model as endochondral ossification begins |
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How many nutrient artery and veins are located in most bones? |
One except a few bones like the femur. |
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Where do nutrient artery and veins enter the bone? |
Nutrient foramina located in the diaphysis |
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What are metaphyseal vessels? |
Blood vessels that supply the inner (diaphyseal) surface of each epiphyseal cartilage. |
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Where are periosteal vessels |
Blood vessels that are from the periosteum. Provide blood to the superficial osteons of the shaft. |
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What other vessels does the periosteum contain? |
Lymphatic and nerve vessels |
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What does bone remodeling mean? |
Continuous Recycling and renewing the organic and mineral components of the bone matrix |
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What are the two functions of bone remodeling? |
1. Renews bone tissue before deterioration. 2. Redistributes Matrix along the lines of stress. |
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Remodeling formation memes? |
Osteoblasts secrete osteoid calcification via local chemical cues |
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Remodeling reabsorption means? |
Destruction of Matrix via osteoclast |
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How does exercise affect bones? |
As you exercise you create robust bones. robust bones are formed because stressing the hydroxyapatite crystals generate small electrical fields that attract osteoblast. Osteoblasts then lay down more bone. |
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What happens if you don't exercise? |
You lose bone density |
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What minerals are required for bone growth? |
Calcium, phosphate, and others like magnesium, fluoride, iron, and maganses (in small amounts) |
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What does vitamin A do for bone growth |
Stimulates osteoblast activity |
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What does vitamin B12 do for bone growth? |
Stimulates protein synthesis and cell division |
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What does vitamin C do for bone growth? |
Collagen production in turning osteoblast into osteocytes |
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What does vitamin D do for bone growth? |
Calcium absorption in intestine and kidneys |
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What does vitamin K do for bone growth? |
Formation of osteocalcin a protein involved in calcification of osteoid |
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What hormones affect bone growth in childhood? |
Thyroxine, human growth hormone (HGH), insulin-like growth factors (IGFs) |
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What does thyroxine do for bone growth? |
Increases osteoblast activity |
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What does HGH do for bone growth? |
IGF secretion |
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Where is IGF hormones located |
Bone and liver tissue |
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What do IGFs do for bone growth |
Chondrocyte division at epiphyseal plate. Collagen synthesis. Increases osteoblast activity |
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What effect bone growth after adolescence? |
Sex steroids from gonads and adrenal glands |
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What does sex steroids have on bone growth? |
Simulates growth via protein synthesis |
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Why are males taller than women? Why do females grow quicker? |
Estrogen rapid growth then other androgens. Faster growth means the epiphyseal plate closes quicker. |
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Why do we need calcium? |
Nerve, muscle, and some enzyme functions. Blood clotting. Calcium is an intracellular secondary messenger. |
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The skeletal system stores how much of the body's calcium? |
99% |
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What is a good range of blood calcium level |
9 to 11 mg per 100 ml |
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What is the average blood calcium level? |
9. 4 mg per hundred ml |
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What happens in hypercalcemia? |
Sodium levels decrease permeability of neurons cardiac arrest |
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What happens in hypocalcemia? |
Respiratory arrest. Increase in sodium permeability of neurons |
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How does bone regulate calcium balance? |
Bone deep disposition and Bone reabsorption |
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What two hormones govern bone disposition and reabsorption? |
Parathyroid hormone and calcitonin |
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Repair of a fracture Step 1 |
Post six to eight hours after fracture, fracture hematoma (a large blood clot) formation closes off injured blood vessels and leaves fibrous meshwork in damaged area. The distribution of circulation kills osteocytes leaving damaged area larger. Last for several weeks. However, cleaned up by phagocytes. Fiberglass and blood vessels invade area. |
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Repair a fracture Step 2 |
Calcification formation. The cells from the intact endosteum and periosteum undergo rapid cell division. Daughter cells move to fracture Zone. Internal callus forms a network of spongy bone and unites the inner edges of the fracture. And external callus of cartilage and bone in circles and stabilizes the outer edge of the fracture |
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Repair of the fracture step 3 |
spongy bone formation. Osteoblasts replace the central cartilage of the external callus with spongy bone which unites the broken ends. Broken fragments and Bone closest to the fracture or broken down and reabsorbed and replaced (last three to four months) |
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Repair of fracture step 4 |
Compact bone formation. Overtime the swelling marks will be remodeled by osteoblast and osteoclast |
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What is osteoporosis? |
A decrease in bone density |
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When is bone density at its greatest? |
20 to 35 years old |
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What are some possible causes for osteoporosis? |
Malnutrition (not enough protein) Hypo vitamin C or D Stress-cortisol reduces disposition Menopause-lack of estrogen Decline in protein synthesis with age Decline in intestinal calcium ion absorption with age Lack of use |
