Term
| What are the two types of cartilage in a growing bone, and where are they? |
|
Definition
Hyaline cartilage covering the surface of the bone where joints articulate
Episeal line |
|
|
Term
| Where are red and yellow marrow found in adults? |
|
Definition
Yellow - in the center of the bone
Red (Adults) - in the head of the femur and humerus, ribs, skull, sternum (remainder of axial skeleton) |
|
|
Term
| True or false: Kids have red marrow in most of their bones |
|
Definition
|
|
Term
| Are mature bones metabolically active? |
|
Definition
| Yes - they maintain their own growth and remodeling |
|
|
Term
|
Definition
| thin layer of connective tissue that lines outside of bone; source of bone stem cells (unspecialized base cells) |
|
|
Term
| Why isn't your entire body made of Compact Bone? |
|
Definition
| weight - compact bone is very heavy |
|
|
Term
|
Definition
adds strength without adding weight
space for blood cells to form |
|
|
Term
|
Definition
| stem cells found in endosteum, periosteum, and central canals |
|
|
Term
|
Definition
| Former osteoblasts that have become TRAPPED IN THE MATRIX |
|
|
Term
|
Definition
| Tiny cavities where osteocytes reside |
|
|
Term
|
Definition
| little channel that connect lacunae |
|
|
Term
| What do we mean when we say bone is a "composite"? |
|
Definition
| Made of multiple structural materials - a CERAMIC and a POLYMER (think of composite bats - both light and strong) |
|
|
Term
| What gives bones their flexibility? |
|
Definition
|
|
Term
|
Definition
| lack of calcium salts that cause the bones to become soft |
|
|
Term
|
Definition
| Brittle bone disease (lack of collagen, or lower proportion of collagen to salts) |
|
|
Term
| Three types of Osseous Tissue |
|
Definition
Compact Bone
Spongy Bone
Marrow |
|
|
Term
|
Definition
| Like onion circles; layers of matrix |
|
|
Term
|
Definition
| Area that includes the concentric lamellae and the Haversian Ccanal |
|
|
Term
|
Definition
trabeculae (thin plates of bone)
Spaces filled with red marrow |
|
|
Term
| HOw are trabeculae laid out? |
|
Definition
| In the orientation that will best support the bone based on the places pressure will be applied (lines of stress) |
|
|
Term
| What are the main methods of bone growth |
|
Definition
Intramembranous Ossification - produces flat bone
Endochondral Ossification - comes from chondroctyes (cells in cartilage) |
|
|
Term
|
Definition
| gelatinous embryonic connective tissue derived from mesoderm |
|
|
Term
| What type of cells does the Mesenchyme give rise to? |
|
Definition
|
|
Term
| What percentage of our bone remodels per year? |
|
Definition
|
|
Term
| Why does bone have to remodel itself? |
|
Definition
| to repair microfractures, release minerals into blood, reshape bones in response to use and disuse |
|
|
Term
|
Definition
| bone remodels due to mechanical stress that is placed on it (how braces work - Maxilla is remodeled as tension is placed on teeth) |
|
|
Term
| What is appositional growth |
|
Definition
| Bones widen throughout life due to the stress placed on them over time |
|
|
Term
| What happens in achondroplastic dwarfism? |
|
Definition
| Long bones stop growing in childhood - this is why the torso is normal but limbs are short |
|
|
Term
| What happens in Pituitary Dwarfism? |
|
Definition
| This is from lack of growth hormone - proportions will be normal - all bones stop growing as opposed to just the long bones |
|
|
Term
| What serves as a calcium reservoir for the body? |
|
Definition
|
|
Term
| Why is destroying calcium homeostasis a problem? |
|
Definition
| disrupts the function of other organ systems, especially NERVOUS and MUSCULAR |
|
|
Term
|
Definition
| crystallization process in which calcium phosphate and other ions are taken from the blood plasma and deposited in bone tissue |
|
|
Term
|
Definition
| dissolving bone (releases minerals into the blood) |
|
|
Term
| Calcium regulation is linked to which other mineral? |
|
Definition
|
|
Term
| What processes need calcium? |
|
Definition
| neuron communication, muscle contraction, blood clotting, and exocytosis |
|
|
Term
|
Definition
|
|
Term
| What components of the body require phosphate? |
|
Definition
| DNA, RNA, ATP, phospholipids, and pH buffers |
|
|
Term
| Why does the body deposit minerals in the skeleton |
|
Definition
| to retain them for withdrawl when they are needed later, like a mineral savings account |
|
|
Term
| Which hormones regulate calcium homeostasis? |
|
Definition
| Calcitriol, Calcitonin, and Parathyroid |
|
|
Term
| What organs are necessary in the production of Calcitriol? |
|
Definition
|
|
Term
| What is the process of Calcitriol creation? |
|
Definition
The keratinocytes of the epidermis use UV to convert a steroid (7 dehydrocholesterol) to previtamin D3.
The liver adds a hydroxyl group to make Calcidiol.
Kidneys add another hydroxyl group to make Calcitriol |
|
|
Term
| How does Calcitriol behave? |
|
Definition
| as a hormone that raises blood calcium concentration |
|
|
Term
| What functions does Calcitriol perform? |
|
Definition
increases calcium absorption by the small intestine
Increases calcium resorption from the skeleton
Promotes kidney reabsorption of CA ions so there is less loss in urine |
|
|
Term
|
Definition
| secreted by C cells (clear cells) of the thyroid gland when calcium concentration rises too high |
|
|
Term
| What function do C cells (clear cells) of the thyroid have in calcium regulation |
|
Definition
| C cells release Calcitonin |
|
|
Term
|
Definition
|
|
Term
| Why does Calcitonin inhibit osteoclasts? |
|
Definition
| Because calcium levels in the blood are too high. Osteoclasts break down bone to release calcium, so they need to be STOPPED when levels are high |
|
|
Term
| What does Calcitriol do to blood calcium? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| Why does Calcitonin need to stimulate osteoblasts? |
|
Definition
| Calcitonin is used when calcium levels are too high. It stimulates osteoblasts to help grow bone in which to deposit extra calcium |
|
|
Term
| Where can Calcitriol access calcium? |
|
Definition
| intestines, kidneys, bones |
|
|
Term
|
Definition
| secreted by the parathyroid glands which adhere to the posterior surface of the thyroid gland; raises blood calcium |
|
|
Term
| How does PTH affect osteoblasts? |
|
Definition
|
|
Term
| How does PTH affect osteoclasts? |
|
Definition
|
|
Term
| HOw does PTH affect the kidneys |
|
Definition
| promotes calcium reabsorption by the kidneys - instead of losing calcium in the urine, PTH encourages the kidneys to reabsorb Ca to maintain levels |
|
|
Term
| HOw does PTH affect calcitriol? |
|
Definition
| promotes the final step of calcitriol synthesis by the kidneys, enhancing calcium-raising effect of the calcitriol |
|
|
Term
| Which has a stronger affect on bone growth: estrogen or testosterone? |
|
Definition
|
|
Term
| How do Anabolic steroids stop growth? |
|
Definition
| epiphyseal plate closes prematurely |
|
|
Term
|
Definition
| deals with the prevention and correction of injuries and disorders of bones, joints, and muscles |
|
|
Term
| What is a stress fracture? |
|
Definition
| break caused by abnormal trauma to a bone (falls, athletics, military combat) |
|
|
Term
| What is a pathological fracture? |
|
Definition
| break in a bone weakened by some other disease (bone cancer, osteoporosis) |
|
|
Term
| How are fractures classified? |
|
Definition
| by structural characteristics |
|
|
Term
| What are the structural characteristics of bone fractures? |
|
Definition
| Nondisplaced (crack but bone not shifted), displaced, Comminuted, Greenstick (breaks in one place and splinters on the opposite side - like breaking a twig) |
|
|
Term
| How does a broken bone heal? |
|
Definition
blood rushes to the area
deposition of collagen, forms a soft callous to glue the fracture temporarily
spongy bone begins depositing on collagen fibers
compact bone remodels along the outside (often leads to calcium deposits on the outside of the fracture) |
|
|
Term
| Types of treatment for fractures |
|
Definition
Closed Reduction
Open reduction
Cast
Traction
Electrical Stimulation |
|
|
Term
| Why is breaking the femur especially dangerous? |
|
Definition
| strong muscles of the thigh can pull the bones on top of each other; this movement can penetrate the femoral artery |
|
|
Term
| What is the most common bone disease? |
|
Definition
|
|
Term
|
Definition
| bone loses mass and becomes brittle due to loss of organic matrix and minerals |
|
|
Term
| What type of bone does osteoporosis mainly affect? |
|
Definition
|
|
Term
| Why does osteoporosis affect spongy bone most? |
|
Definition
| because this bone is the most metabolically active |
|
|
Term
| Why is the widow's hump (kyphosis - caused by osteoporosis) a problem? |
|
Definition
| it can cause breathing problems along with mobility problems |
|
|
Term
| HOw does estrogen affect bone density? |
|
Definition
| inhibits resorption by osteoclasts |
|
|
Term
| What do drugs like Fosomax and Actonel do? |
|
Definition
| destroy osteoclasts to treat osteoporosis |
|
|
Term
| What dietary components help prevent osteoporosis? |
|
Definition
|
|
Term
| Why is exercise important for prevention of osteoporosis? |
|
Definition
| bones develop according to use |
|
|
