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33 Cards in this Set
- Front
- Back
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Describe bones (3). |
* Osseous tissue * Supports, protects and creates skeleton * Derived from mesenchyme calcium phosphate matrix |
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What are the functions of Bone? (4) |
* Shape, support & body structure * Supports & protects soft tissues & organs * Provides points of attachment for muscles * Store inorganic salts & minerals |
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What are the two types of Bone? |
Compact & Spongy |
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Describe Compact Bone (2). |
* Found on the outside of bone * Used for muscle attachment |
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Describe Spongy Bone. (2) |
* The internal layer of bone * Chemically similar to compact bone |
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What are the Components, Cells, Fibers, ECM & Features of Bone Tissue? |
* Compact & Spongy * Cells: Osteoblasts & Osteocysts * Matrix: Gel-like ground substance calcified with inorganic salts * Fibers: collagen * Features: hard tissue that resists compression & tension; functions in support |
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What are the two major regions of the skeleton and what bones do they include? |
* Axial Skeleton: Skull, vertebral column & rib cage * Appendicular Skeleton: Upper & lower limbs and Girdles (shoulder & hip bones) |
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What are the 5 shapes of bones? |
* Long Bones (tibia, femur) * Short Bones (wrists, ankles) * Flat Bones (skull, sternum, ribs, scapula) * Irregular Bones (vertebrae) * Wormian Bones (small bones between major ones, like in skull sutures) |
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What are the parts of Long Bones. |
* Epiphysis * Epiphyseal Line * Diaphysis * Articular Cartilage * Periosteum * Endosteum * Medullary cavity * Trabeculae * Bone Marrow |
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What is the Epiphysis? (2) |
* Ends of the bone, distal & proximal * Mostly spongy bone with a thin layer of compact bone |
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What is the Epiphyseal Line? |
Remnant of the epiphyseal plate |
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What is the Diaphysis? (4) |
* The shaft * Has central medullary cavity filled with yellow marrow * Surrounded by compact bone * Bones are thickest in the middle of the Diaphysis |
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What is the Articular Cartilage? (3) |
* On the ends of bone * Remnant of original embryonic skeleton * Shock absorber |
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What is the Periosteum? (2) |
* Double layered tissue around the bone * Contains blood, lymph vessels & nerves |
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What is the Endosteum? |
* Inside the bone * Inner layer of medullary cavity |
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What is Trabeculae? |
A honeycomb of small needle-like or flat pieces inside spongy bone |
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Where do you find Bone Marrow and what does it do? |
* Red Marrow: red marrow cavities; red blood cells * Yellow Marrow: in shafts of long bones; energy storage |
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What is Hematopoiesis? |
* Blood cell formation * Occurs in the red bone marrow |
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What is an Osteoblast? (3) |
* Bone forming cells; deposit bone * Secretes collagen * When surrounded by collagen, will mature into osteocytes |
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What is an Osteoclast? (3) |
* Bone resorption * Large, nucleate cells * Excrete enzymes to break down bone (Look like the ghosts from Pac-Man!) |
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What is Appositional Bone Growth? (5) |
* Bone formation at the surface of the bone produces ridges that parallel a blood vessel * The ridges enlarge and create a deep pocket * The ridges meet and fuse, trapping the blood vessel inside the bone * Bone deposition then proceeds towards the vessel creating an Osteon * Osteoblasts under the periosteum secrete bone |
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How does physical stress affect bone growth? |
It stimulates bone growth |
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How do deficiencies of Vitamins A, C & D affect bone growth? |
* Vitamin A: retards bone growth * Vitamin C: Results in fragile bones * Vitamin D: Rickets; Ostemalacia |
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How does Growth, Thyroid & Sex Hormones affect bone growth? |
* Insufficient GH: dwarfism * Excessive GH: Gigantism; Acromegaly * Insufficient Thyroid Hormone: Delays bone growth * Sex Hormones: Promote bone formation; Stimulates ossification of epiphyseal plates |
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What is Wolff's Law? (2) |
* Bone is deposited in response to stress * Usually where there are muscle attachment points |
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What is the Haversian System? (4) |
* The structural unit of compact bone * Also called the Osteon * An elongated cylinder, parallel to the long axis of the bone * Tiny, weight bearing pillars |
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What is a Haversian Canal? |
* Also called a Central Canal * Contains small blood vessels & nerve fibers that serve the osteon cells |
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What are Volkmann's Canals? (3) |
* Also called Perforating Canals * Lie at right angles to the long axis of the bone * Connect the blood and nerve supply of the periosteum to the central canal or medullary cavity |
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What are Osteocytes? |
* Mature bone cells * Monitor & maintain the bone matrix * Act as stress sensors * Transport nutrients & wastes |
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What is Intramembranous Ossification? (3) |
* Forms the cranial bones of the skull & the clavicles * Most bones formed this way are flat bones * Begins in utero @ 8 weeks development |
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What are the four steps of Intramembranous Ossification? |
* Proliferation Zone: Cartilage cells undergo mitosis * Hypertrophic Zone: Older cartilage cells enlarge * Calcification Zone: Matrix calcifies; Cartilage cells die; Matrix begins deteriorating; Blood vessels invade cavity * Ossification Zone: New bone forms |
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What is Endochondral Ossification? |
* Formation of all bones below the clavicle * Beginning late int he second month of development * Uses hyaline cartilage "bones" formed earlier as models for bone construction * More complex that Intramembranous Ossification |
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What are the five steps of Endochondral Ossification? |
1. Bone collar forms around the diaphysis of the hyaline cartilage model 2. Cartilage in the center of the diaphysis calcifies and develops cavities 3. The Periosteal bud invades the internal cavities and spongy bone forms 4. The diaphysis elongates and a medullary cavity forms; Secondary ossification centers appear in the epiphysis 5. The epiphysis ossifies. When completed, hyaline cartilage remains only in the epiphysis plates and articular cartilages. |
