Part 1 Flashcards
What are the functions of the bone and the skeletal system?
- For protection and assistance on movement
- For blood generation - red bone marrow
- Triglyceride storage - Yellow bone marrow
- Mineral homeostasis
Describe the structure of the bone
Diaphysis - Main shaft of bone Epiphyses - Proximal and distal end Metaphyses - Neck region (Epiphyseal line - growth) Articular cartilage Periosteum Medullary cavity and endosteum
What is calcification?
It is the deposition of minerals in a framework provided by collagen.
What does calcium phosphate and calcium hydroxide form?
It forms Calcium hydroxyapatite
Where does mineralization occur?
It occurs between spaces in collagen, there is an increase in mineral content around collagen.
What occurs when mineralization starts to form around the collagen?
Start to see crystalline salts forming around collagen which increases hardness of the structure.
What does collagen provide?
It provides tensile strength and elasticity
What does osteogenic cells do?
They are stem cells which can differentiate into osteoblasts, in the inner periosteum and endosteum as wellas in the cannals within bone.
What do osteobalsts do?
They synthesis and secrete collagen fibers for extracellular matrix and can also become osteocytes. (they also form bone matrix)
What are osteocytes and what do they do?
They are mature bone cells that maintain regular bone metabolism of exchange in nutrients and blood, they do not divide (post mitotic cells) (main bone tissue)
What is resortion?
The breakdown of extracellular matrix
What are osteoclasts and what do they do?
They are large cells formed by fusion of around 50 monocytes mostly in endosteum and they produce lysosomal enzymes to break down extracelluar matrix
The medullary cavity is where you find spongy bone leading to compact bone. TRUE OR FALSE?
TRUE
What percentage of bone structure is compact bone?
80%
Compact bone is the main structure for protection, movement and resistance to mechanical stress related to movement and weight. TRUE OR FALSE?
TRUE
What are volkmann cannals?
They are cannals where blood vessels passes through the bone, these have concentric lamellae which form around these blood vessels.
What forms the osteons?
They are formed by blood vessels in the volkmann cannals surrounded by concentric lamellae
What forms between osteons?
Interstitial lamellae forms in between osteons
Lamellae in the in the lattice of columns makes up most of short, flat and irregular bones. TRUE OR FALSE?
TRUE
Hemopoesis occurs in the red bone marrow within the trabeculae. TRUE OR FALSE?
TRUE
Describe function of periosteum?
Rich in sensory nerves
Sensitive for tearing or tension
Severe pain from fractures or bone tumors
What is bone remodelling?
Removal of old bone tissue with a new one
What is bone resportion and deposition?
Resorption is the removal of minerals and fibers by osteoclasts
Deposition is the deposition of minerals and fibers by osteoblasts
What are the benefits for bone remodeling?
Bones can become stronger and shape can be altered
What factors affect bone remodeling?
Vitamins
Hormones
Minerals
Vitamin A stimulates osteoblasts, Vitamin C for collagen sythesis vitamin D increases bone resorption fro GIT and vitamin K and B12 synthesis bone protein. ARE AL THESE STATEMENTS TRUE PR FALSE?
TRUE
Describe the events of Formation of fracture hematoma
clot 6-8 hours after injury/circulation at site of injury stops and bone cells die in this area, causing swelling, inflammation and phagocytosis - osteoclasts activity.
Describe the events of fribrocartilaginous callus
fibroblasts from periosteum migrate and produce collagen, chondroblasts produce fibrocartilage which takes around 3 weeks.
In bone remodeling compact bone is not replaced with spongy bone. TRUE OR FALSE?
FALSE
in bony callus formation fibrocartilage is converted to spongy bone. TRUE OR FALSE?
TRUE
Bone is the main reservoir of calcium ions. TRUE OR FALSE?
TRUE
Changes in calcium levels can have serious consequences, such as increasing cardiac arrest and decrease in respiration. TRUE OR FALSE?
TRUE
Bone releases Ca by osteoclasts if levels decrease and absorbes Ca by osteoblasts if levels increase. TRUE OR FALSE?
TRUE
Calcitrol is not the active form of vitamin D. TRUE OR FALSE?
FALSE
Parathyroid hormone works to increase plasma calcium. TRUE OR FALSE?
TRUE
What does calcitonin do?
It reduces calcium serum, by inhibiting osteoclasts, which increases calcium deposition in the bone
What disease can calcitonin be used to treat?
Osteoporosis, slowing bone resorption
What are metabolic bone diseases?
Groups of disorders where there are disturbance in bone formation and resorption
What are the different types of metabolic bone diseases?
Osteoporosis (common) loss of height/fractures
Paget’s disease (common) pain in hips
Osteomalacia (uncommon) it is generalized bone pain and muscle weakness
What is osteoporosis?
It is a generalized reduction of bone mass/ increased fragility and predisposition to fractures
There is an accelerated bone loss in females during menopause. TRUE OR FALSE?
TRUE
Males do not tend to develop osteoporosis due to administration of glucocorticoids. TRUE OR FALSE?
FALSE
What are the etiological factors for osteoporosis?
Genetic factors
Age
Administration of glucocorticoids
Menopausal women
What do bisphophonates and strontium ronelate do?
Bisphophonates inhibits resorption
Strontium ronelate inhibits resorption and stimulates formation
What are the complications of paget’s disease?
Enlarged skull
Nerve decompression
deafness
Development of osteosarcoma
What is osteomalacia?
Inadequate mineralization of osteoids, softening of bones. Most cases are due to lack of vitamin D
What are the treatment of osteomalacia?
Treat with sun exposure and vitamin D
