Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
3 Cards in this Set
- Front
- Back
|
1) List the components of the matrix of bone and describe how each component contributes to the bone’s strength
|
• Extracellular Matrix (15% water, 30% collagen fibers, and 55% crystallized mineral salts)
o Ground Substance- Contains organic and inorganic components (noncollagenous proteins) • Gets calcified • Glycosaminoglycans-GAG • Glyocoproteins= polysaccharide+protein (made of glycoproteins) • Chondrotin sulfate and Hyaluronic acid • Negatively charged- trap water; initial structure is not hard • Inorganic components • Water • Hydroxyapatite Ca10 (PO4)6 (OH)2 o Ca3 (PO4)2 + Ca(OH) 2 (Calcium phosphate (most abundant) and calcium hydroxide) + other minerals (calcium carbonate) and some ions (Mg, F, K) o As crystals form tissue hardens- calcification which is initiated by bone-building cells called osteoblasts • Hardness depends on crystalized inorganic mineral salts…soaking a bone in acidic solution like vinegar, dissolves mineral salts, causing bone to be rubbery and flexible • Rickets- skeletal disorder (inorganic component deficient); calcium deficiency leads to lack of vitamin D leads to flexible bones (bowed legs) o Fibers- Organic compound, collagen fibers • Collagen Fibers Type 1 • Fibrous protein arranged in helical form o The collagen fiber contains mineralized fibrils o The fibrils contain small mineral plates bound by helical noncollagenous proteins (collagen cross links) • Very resistant to pulling forces • Provides flexibility to allow for shock absorption and a framework for deposition of calcium crystals to harden the full structure, the spaces are where deposition can happen to allow for solidification • Flexibility depends on its collagen fibers…apply proteolytic enzymes (denature protein) removes collagen from bone, bone becomes brittle/crumbly • Scurvy- skeletal disorder (organic component deficient); problem with collagen synthesis due to vitamin C deficiency leads to brittle bones that can fracture easily Other important Info: • Organization of organic/inorganic components: o Salts (hydroxyapatite) are deposited within collagen fibers o As the hydroxyapatite condenses, other inorganic salts and ions precipitate in the matrix to fill in the spaces between fibers |
|
|
2) Describe the differences between compact and spongy bone in terms of location, function, and composition.
|
• Both have the same chemical composition but different organization
• Spongy Bone- red bone marrow is associated with Spongy Bone..most common=hip bone o Organization- irregular lattice of thin plates called trabecullae; osteocytes housed in lacunae o Location- epiphyses of long bones; surrounding marrow cavities; always in interior of bone; flat, short, and irregular bones o Functions- withstand forces from many directions- trabecullae arranged along lines of stress; lightens the skeleton (not as strong as compact bone); contains red marrow for hemopoiesis o Composition- Lacunae, canaliculi, osteocytes, Concentric lamellae, trabeculae • Compact Bone o Organization-solid network of bone organized in concentric ring structures called osteons ; needs more canals because it is more dense and needs a way to provide nutrients through bones o Location-External layer of all bones; diaphysis of long bones o Function- gives long bones ability to withstand forces along longitudinal axis o Composition- Central canals, perforated canals, osteons, interstitial lamellae, perforating fibers, circumferential lamellae, perforating canals, caniliculi, lacunae, concentric lamellae |
|
|
3) Describe the microscopic structure of compact bone (the osteon) and understand the purpose of its organization
|
• Osteon- functional unit of compact bone
o Central Canal- where the blood vessels are; vessels allow nutrients diffuse from cell to canaliculi to cells and to lacunas o Blood vessels- in the central canal; arteries with capillaries, vein, and nerve fiber also in central canal o Lymphatic vessels- in the central canal o Concentric Lamellae – circular plates of mineralized extracellular matrix, increasing diameter, surrounding small network of blood vessels, lymphatics, and nerves located in the central canal. They have collagen fibers that allow twisting force o Osteocyte- is in the lacuna and canaliculi o Lacuna- small spaces between the concentric lamellae, looks like lake that osteocyte is in o Canaliculi- go in all directions from the lacunae (to connect lacunae with one another and central canals) and are filled with extracellular fluid; inside the canaliculi are fingerlike processes of osteocytes (dendrites)…little canals o Cytoplasmic extension (dendrite) of osteocyte |
