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54 Cards in this Set
- Front
- Back
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What are the 7 functions of the bone?
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Support, movement, protection, blood formation, electrolyte balance, acid-base balance, detoxification
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os, osse, oste, osteo all mean what?
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Bone
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What is the function of long bones?
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For muscle attachment and movement
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What is the function of short bones?
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They have limited motion and muscle attachment
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What is the function of flat bones?
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Protect organs and provide a broad surface for muscle attachment
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What is the function of irregular bones?
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They have this shape because they have many functions
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Bones have an outer shell of dense white osseous tissue called?
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Compact bone
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Enclosed in the compact bone is a more loosely organized form of osseous tissue called?
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Spongy bone
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What is the diaphysis?
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The shaft of the long bone, which provides leverage
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What is the epiphysis?
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The expanded head at each end of a long bone, is filled with spongy bone. It is enlarged to strengthen the joint and provide added surface area for the attachment of tendons and ligaments.
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What is the medullar cavity?
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A cavity filled with bone marrow that is surrounded by a cylinder of compact bone in the diaphysis.
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What is the epiphyseal plate?
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It is the area of bone in children and adolescents who are still growing. It is the hyaline of cartilage that separates the marrow spaces of the epiphysis and diaphysis. It is the point where bones grow in length
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When one is not growing any longer what does the epiphyseal plate turn into?
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The epiphyseal line and is no longer a transparent line on an x-ray.
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What is the periosteum?
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The area around the surface of the bone which has nerve endings
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What is the endosteum?
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The internal lining of the bone
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What is at the end of most adjoining bones and enables the joint to move more easily with the lubricating fluid?
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A thin layer of hyaline cartilage called Articular cartilage
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What are perforating fibers?
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In the periosteum the some of the outer fibrous layer of collagen fibers are continuous with the tendons that bind muscle to bone and some penetrate into the bone matrix
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What is the osteogenic layer of the periosteum responsible for?
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Important to the growth of bone and healing of fractures
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What is the nutrient foramina?
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The minute holes in the periosteum bone that blood vessels penetrate through
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What is red bone marrow?
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They typical type of bone marrow found in the medullary cavity of children and gets its color from the abundance of red blood cells
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What is the yellow bone marrow characterized by?
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With age the red bone marrow is gradually replaced by fatty yellow bone marrow. Yellow bone marrow no longer produces blood, but in the case of severe anemia it can transform back to red marrow.
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What are osteogenic cells and where are they found?
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They are stem cells found in the endosteum. They are mitotic and multiply continually.
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What is the function of osteoblasts?
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They are bone forming cells located in the endosteum and periosteum that synthesize bone matrix.
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What is the function of osteocytes?
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Former osteoblasts that have become trapped in the matrix they deposited. They are connected to eachother by slender channels called canaliculi that form a junction to allow them to pass nutrient and chemical signals to each other and to transfer waste to the nearest blood vessel for disposal
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What are osteoclasts?
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Bone dissolving macrophages found on bone surfaces.
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Why are osteoclasts multinucleated?
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They are formed from several stem cells fused together
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Where in the bone are osteoclasts found?
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Periosteum and endosteum
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How do osteoclasts absorb bone?
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They release HCl which dissolves the minerals of the adjacent bone
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What happens when there is too much osteoclast activity?
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Osteoblasts compensate by adding extra bone in a rapid and disorderly fashion, which then produces weak and deformed bones. Seen in Paget disease
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What is the osteoblast and osteoclast activity that characterizes osteoporosis?
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Osteoblasts become less active and osteoclast activity remains the same or increases.
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What type of bone does osteoporosis effect?
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Spongy bone, which becomes very porous and brittle
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Who is most susceptible to osteoporosis and why?
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Woman have a greater chance than men. Because they have less bone mass, lose it earlier and faster and they have a decrease in estrogen due to menopause (estrogen keeps osteoblasts active and suppresses osteoclasts).
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What is the central canal?
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The area surrounded by the osteon and contains blood vessels and nerves that bring nutrients and blood to diffuse.
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What is the osteon?
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The circular formation of bone around the central canal
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What is the perforating canal?
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The diagonal passage of blood vessels and nerves into the central canals
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What is the canaliculi?
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The slender channels extending from osteocytes that allow osteocytes to pass nutrients and chemical signals to eachother.
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What is the trabeculae and where is it found?
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It is the thin plates found in which are connected to eachother by spicules to form the structure of spongy bone.
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Who receives nutrients from the central canals?
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The osteocytes receive nutrients from the blood vessels and pass them through their gap junctions to neighboring osteocytes. They also receive waste from their neighbors and convey them to the central canal for removal from the blood stream
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What is the organic bone comprised of and what benefit does this bring to the bone?
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It contains collagen and protein-carbohydrate complexes, which give the bone its flexibility and strength similar to fiberglass
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What happens when the bones lack collagen?
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The bone becomes very brittle. A joggers bones would shatter under the impact of running.
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What is the inorganic portion of bone comprised of and what does this do for the bone?
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It is comprised of calcium phosphate salts, magnesium, sodium, potassium, etc. These give the bone strength and the ability to resist compression.
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What happens when bones are deficient in calcium salts?
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They become soft and bend easily and this is a characteristic is the disease rickets.
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What causes rickets?
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When a child is deficient in vitamin D, making it hard to absorb enough dietary calcium to adequately harden the bones. The legs become bowed outward by the weight of the body.
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What does Wolff's law of bones state?
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The architecture of a bone is determined by the mechanical stresses placed upon it, and the bone adapts to withstand those stresses. The form of a bone is shaped by its functional experience
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What happens when bone is little used?
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Osteoclasts remove matrix and get rid of unnecessary mass
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What happens when bone is heavily used or stress is consistently applied to a particular region of a bone?
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Osteoblasts deposit new osseous tissue and thicken the bone
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How do corticosteroids affect bone resorption or deposition?
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They can cause osteoporosis like symptoms: reduce osteoblast activity and increase osteoclast activity
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What do estrogen and testosterone do to bone resorption or deposition?
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Increase osteoblast activity
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How does caffeine affect bone resorption or deposition?
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It binds Ca so it is excreted
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How does smoking affect bone resorption of deposition?
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Decreases osteoblast production, impairs Ca absorption, interferes with ERT (estrogen replacement theory)
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What is Kyphosis?
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An exaggerated thoracic curvature in people with osteoporosis. As the bodies of the vertebrae lose spongy bone they become compressed by the body weight.
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Bone resorption
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osteoclast activity
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Bone deposition
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Osteoblast activity
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What is the focus of osteoporosis treatment?
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Aimed at slowing the rate of bone resorption. The drugs are bis-phosphates (Actonel, Fosomax) and they destroy osteoclasts
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