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71 Cards in this Set
- Front
- Back
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What is the skeletal system composed of?
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bones, cartilage and ligaments
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Skeletal system functions include:
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support, protection, movement, electrolyte blanace, acid balance, and part of blood formation.
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Support:
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holds the body up and supports the muscles
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Movement:
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Limb movement and breathing action of muscle on bone.
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Protection:
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Enclose and protect brain, spinal cord, heart and lungs.
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Electrolye balance:
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Calcium and phosphate ions.
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Acid Base Balance:
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Buffers blood against excessive pH changes.
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Parts of blood formation:
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Red bone marrow is the chief producer of blood cells.
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What are the types of bone cells?
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Osteoblast, osteocyte and osteoclast.
(there is more but don't need for class) |
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Osteoblast:
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bone forming cells. secrete soft organic matter of matrix which hardens by mineral deposition.
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Osteocyte:
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Mature bone cell found in bone tissue. Maintain the protein and mineral content of the surrounding matrix through the turnover of matrix components. Secrete chemicals that dissolve adjacent matrix and minerals and enter circulations.
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Osteoclasts:
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are cells that remove and reclye bone matrix. (breaks down bone to let out(release calcium phosphate. Clean up extra bone-such as in healing.)
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Describe the bone matrix: inorganic and organic?
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Bone tissue matrix is dry weight about 1/3 organic and 2/3 inorganic.
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Organic Matter
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Synthesized by osteoblasts.
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Examples of Organic Matter:
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Callagen, carbohydrates, protein complexes such as glycosaminoglycan's, proteoglycans, and glycoproteins.
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Inorganic Matter:
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85% hrdroxyapatite (crystalized clacium phospahate salt)
10% calcium carbonate and other minerals flouride sodium, potassium and magnesium. |
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Describe the compact bone tissue-the specific arrangement.
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Osteon, central canal, perforating canals, and concentric lamellae.
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Osteon:
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Basic structrural unit of compact bone(cylinder of tissue around central canal)
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Central Canal:
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The "Bulls Eye" in each osteon also a vertical canal.
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Perforating Canal
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Extend roughly perpendicular to the surface. Blood vessels in these canals supply blood to osteons, deeper in the bone and to tissues in medullary cavity.
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Concentric lamellae
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Series of nested cylinders around the central canal.
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Describe spongy bone:
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Spongy bone is located where bones are not heavily stressed or where stresses arive from many directions. Spongy bones reduce the weight of the bone making it easier for muscles to move bones. It appears to look like a sponge and has few osteons and no central canal.
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What do you call spongy bone slivers?
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spicules, thin plates of bone (trabecular) and spaces filled with red bone marrow.
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How does spongy bone differ from compact bone?
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because lamellae are not arranged in osteons; there are no capillaries or venueles in the matrix of spongy bone.
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What are the two types of bone marrow?
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Red Marrow and Yellow Marrow.
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What is the significance of red bone marrow?
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Hemopotic tissue produces blood cells and it is composed of multiple tissues.
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How do you get yellow bone marrow?
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Red bone marrow turns into fatty yellow marrow and it no longer produces blood.
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Where can red bone marrow be found?
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Found usually in flat bone located in the skull, vertebrae, ribs and sternum, part of pelvic girdle and proximal heads of humorous and femur.
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How does red bone marrow differ in a child verses adult?
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Red bone marrow is in almost every bone in a child. In adults the red bone marrow is located in the skull, vertabrae, ribs, sternum, part of pelvic girdle and proximal heads of humorous and femur.
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Breifly describe intramembraneous ossification?
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Intramembranous ossification produces the flat bones of the skull and most of the clavicle bone. These bones develop within a fibrous sheet similar to epidermis of the skin(dermal bones) Intramembraneous ossification begins when mesenchymalcells first differentiate into osteoblasts within embryonic or fibrous connective tissue. The location where ossification occurs is called the ossification center. Next the blood vessels begin to grow into the area as specules meet and fuse together; some of these blood vessels become trapped within developing bone. Then, the intramembranous bone consists of spongy bone and remodeling around trapped blood vessels can produce osteons like compact bone.
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Breifly describe endochondrial ossification?
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1. cartilage enlarges chondrocytes near the center of the shaft increase greatly in size. as the cells enlarge lacunae expand and the matrix is reduced to a series of thin struts. The strust then begin to calcify and the enlarged chondrocytes die. 2nd blood vessels grow into cartilage and the cells of the perichondrium convert to osteoblasts. The shaft of the cartilage then becomes ensheathed in a superficial layer of bones.3rd blood vessels penetrate the cartilage and invade the central region. They begin making spongy bone at the primary ossification center. 4 remodeling occursw as growth continues. 5. Capillaries and osteoblasts migrate into the epiphyses creating secondary ossification centers. 6 The epiphysis eventully becomes filled with spongy bone.
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Bone growth
Length (intersitial growth) |
bone elongation is the result of cartilage growth (osteoblasts) within epiphyseal plate
-epiphysis closes when cartilage is gone= epiphyseal line. -length wise growth is then finished (occurs at different ages in different bones-eventually ends) |
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Bone growth
Width (appisitional growth) |
-deposition of new bone at surface
-osteoblasts on deep side of periosteum deposit osteoid tissue(become trapped as tissue calcifies) -lay down matrix in layers parallel to surface;forms circumferential lamellae over surface (osteoclasts of enosteum enlarge marrow cavity). 1.osteoblasts lay bone in periosteum 2. periosteum (connective tissue)reforms around bone 3. Continues throughout life |
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What is bone growth in length called?
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Intersitial growth
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What is bone growth in width called?
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appositional growth
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How much bone remodeling occurs per year?
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10 % per year throughout life
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What is bone remodeling?
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repairs, microfractures, releases minerals into blood, reshapes bones to use and disuse.
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What is Wolff's Law?
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Mechanical stresses placed on it and bones adapt to withstand those stresses.
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Remodeling is a collabrative and precise action of what bone cells?
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Osteoblasts and osteoclasts.
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Bony processes grow larger in response to what?
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Mechanical stress
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What is Mineral Deposition (mineralization)?
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A crystallization process in which calcium phospahte, and other ions are taken from the blood plasma and deposited in bone tissue.
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Name three things that take place during the crystallization process. (Mineral Deposition)
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1. osteoblasts produce collagen fibers that spiral the length of the osteon
2. fibers become encrusted with minerals that harden the matrix. 3. cacium and phospahate (hdroxyapatite) from blood plasma are deposited along the fibers. |
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Mineral Resorption (general processes)
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The process of dissolving bone and releasing minerals into the blood.
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What takes place during Mineral Resorption?
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-perfomed by osteoclasts at the "ruffled border"
-hrdrogen pumps in membrane secrete hydrogen into space between osteoclasts and bone surface -chloride ions follow by electrical attraction -hydrochlorcdi acid (pH4) dissolves bone minerals -acid phosphatease enzyme digest the collagen. |
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What are the functions of Calcitriol? (Activated by Vitamin D)
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-by the sequential action of skin, liver and kidneys
-hormone that raises blood calcium concentration 1. increases calcium absorption by small intestine. 2. increses calcium resortion from skeleton (increases stem cell differentiation into osteoclasts which liberates calcium and phospahate from bone. 3 promotes kidney reabsorption of clacium ions=less loss in urine. -necessary for bone deposition:need adequate clacium and phosphate -abnormal softness of bones (rickets) in children and (osteomalacia) in adults without adequate Vitamin D |
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What are the functions of PTH?
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Releases with low calcium blood levels to increase blood calcium levels.
1. raises osteoclasts population (bind to osteoblasts) and promotes bone resorption. 2. promotes claclium reabsorption by the kidneys=less loss of urine. 3. promotes final step of calcitriol synthesis in kidneys, enhancing clacium raising effect of calcitriol. 4. inhibits collagen synthesis by osteoblasts, inhibi8ti8ng bone deposition. |
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PTH is found?
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Secreated by parathyroid glands which adhere to posterior side of thyroid gland.
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What happens with PTH in the bones:
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Osteoclasts work harder-breakdown bone to release Ca+2
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What happens with PTH in the intestine:
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Absorb more Ca+2
-Ca+2 you ate |
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What happens with PTH in the Kidneys?
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Keep Ca+2 in blood
do not pee as much out |
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What are the functions of Calcitonin?
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Secreted by C cells (clear cells) of the thyroid gland when calcium concentration is to high.
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Functions continued:
Calcitonin lowers blood calcium (2 Ways) |
1st Calcitonin lowers blood by :osteoclast ingibition
-reduces osteoclasts activity as muxh as 70% -less calcium liberated from bones. 2nd way Calcitonin lowers blood by osteoblast stimulation -increases the number and activity of osteoblaasts -deposits calcium into skeleton. |
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Calcitonin in the bones:
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Bones: stop ostoeclasts
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Calcitonin in the Intestines:
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Intestines: won't absorb as much Ca+2
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Calcitonin in the Kidneys:
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pee out more Ca+2
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Pathological Fracture:
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disease process
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Tramatic Fracture:
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Injury, trama to bone
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Two diseases that cause Pathological fractures:
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-Bone cancer
-Osteoporosis |
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Types of traumatic fractures
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Transverse
Spiral Displaced Non-displaced Compression Greenstick Comminuted Epiphyseal Open Pott Colles |
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Healing a fracture:
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1. Fracture Hematoma and granulation tissue(blood clot)
2. Soft Callus Formation-forms spongy bone on inner edges by fibroblasts and chondroblasts depositing collagen and fibrocartilage 3. Conversion to Hard Callus-produced by osteoblasts (cement). 4. Remodeling-dead bone fragments removed/replaced Osteoblasts deposit spongy bone to dridge gaps gradually transformed into compact bone. swelling marks location overtime =remodels |
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Transverse fracture:
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break occurs in shaft across long axis.
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Spiral fracture:
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caused by twisting stresses that spread along length of bone.
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Displaced fracture:
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broken ends of bones are not aligned.
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Non-displaced fracture:
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broken ends of bones are aligned.
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Compression:
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occur in vertebrae due to extreme stresses.
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Greenstick fracture:
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one side of shaft is broken and one side is bent-occurs in children
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Comminuted fracture:
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bone is shattered into many pieces.
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Epiphyseal fracture:
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occurs at epiphyseal plate and could interfere with growth.
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Open fracture:
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bone protrudes outside of skin.
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Pott fracture:
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occurs at the ankle and affects tibia and fibula.
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Colleus fracture:
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occurs at wrist in radius-due to fall onto outstretched hand.
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