Chapter 5 Flashcards
The inorganic matrix of bone is composed of what? (3)
- Hydroxyapatite crystals
- Calcium phosphate
- Other minerals
What are the four main functions of bone?
- Structural support
- Serve as levers for muscles/ locomotion
- Protect organs and house bone marrow
- Metabolic reserve for minerals
The organic matrix of bone is made of?
Collagen, GAG’s, glycoproteins
Which type of GAG’s are more numerous in the organic matrix of bone? Sulfated or nonsulfated
Sulfated (primarily chondroitin and keratin sulfates)
Do adults or children have a Higher percentage of organic matrix?
Children
What is the appearance of an osteoblast?
Cuboid or columnar
What are the two locations that an osteoblast is typically found?
Endosteum and periosteum
What are glycoproteins?
Minerals that bind to collagen
Where are osteoprogenitors derived from?
Mesenchyme cells
What is the function of an osteoprogenitor?
To change into an osteoblast
What is the only bone cell to undergo mitosis?
Osteoprogenitor cell
Which bone cell functions to create an osteoid, Produce an anti-inhibitor that neutralizes CIF, and responds to PTH?
Osteoblast
How does the osteoblast respond to PTH?
Osteoblast produce a factor (OPGL) which causes the creation of more osteoclasts » Osteoblast produce osteoclast stimulating factor » Osteoblast produce proteins/enzymes which condition bone surface for osteoclasts
Which bone cell functions to maintain the matrix?
Osteocytes
What is the small area between the osteoclast and a howships lacuna called?
Subasteoclastic compartment (area of bone reabsorbtion)
PTH directly activates ______ and indirectly activates ________?
Direct - osteoblast
Indirect - osteoclast (osteoblast to produce osteoclast stimulating factor).
What hormone decreases osteoclast activity?
Calcitonin
Primary bone = mature bone? True or False
False
Primary bone or secondary bone have organized collagen 1 fibers?
Secondary bone
Which type of bone is directly under the periosteum?
Outer Circumferential Lamellae/periosteal lamellae
Which part of the bone is close to cancelous bone or marrow cavity?
Inner Circumferential Lamellae/Endosteal Lamellae
What is the name of the tiny channels that carry ostecyte cell processes called?
Canaliculi
Which part of cancellous cone is surrounded by irregular CT filled spaces?
Trabeculae
What are the two main parts of the periosteum?
Fibrous periosteum, and osteogenic periosteum
• distribuute blood vessels and sympathetics
• transition bewtween bone and tendons / ligaments
These functions belong to what part of the periosteum?
Fibrous periosteum
•healing
•growth
•remodeling
Are the functions of which part of the periosteum?
Osteogenic periosteum
Which portion of the bone can be found
•lining cancellous bone
•lining endosteal lamellae
•lining central (haversian canal)
Endosteum
What are the seven general steps for intramembranous ossification?
- Vascular mesenchyme tissue with mesenchyme cells.
- Primary centers of ossification develop
- Spicules and trabeculae of bone form and spread outwards
- Remodeling begins immediately
- Vascular mesenchyme between trabeculae/osteons can develop into bone marrow and endosteum.
- Other ossification centers likely
- All areas of ossification eventually fuse
Describe the progression of cells during the ossification of the primary centers.
mesenchyme cells » osteoprogenitors » osteoblasts » secrete matrix » osteocyte
What are the 5 general steps for endochondral ossification?
- Blood vessel invades middle of perichondrium
- Osteoblasts secrete osteoid just inside the periosteum
- Capillaries from periosteum enter the interior brittle cartilage
- Bone growth advances toward epiphyseal growth plates
- Secondary centers of ossification develop.
When Osteoblasts secrete osteoid just inside the periosteum, what will form?
Periosteal (subperiosteal) collar
What is the importance of the periosteal collar
Prevents diffusion of nutrients and oxygen to the chondrocytes that are still below, causing chondrocytes to die and the matrix to calcify.
the original invading capillary along with osteoprogenitorsand hemopoietic stem cells is known as?
Periosteal bud.
During remodeling the diaphysis will? (4)
a. eliminate calcified cartilage
b. create marrow cavity
c. provide osteon structure
d. create Volkmann’s canals
The bone in metaphysis growing towards epiphysis as cartilage in epiphyseal growth plate continues to develop (grow). This process will result in?
An increase of length
Growth is the osteogenic periosteum will result in an?
Increase of width
What will slow cartilage development in the epiphyseal growth plates?
Hormones involving sexual maturity
Cells from within the bone marrow influence the remodeling of which type of bone?
Cancellous bone
Systemic factors from the osteogenic periosteum and the endosteum influence the remodeling of what type of bone?
Compact bone
Which hormone influences bone growth by Stimulating osteoblast (fibroblast) formation?
Somatotropin
Scurvy is caused by a vit. C deficiency. Which tissue fibers does it affect?
Collagen 1
What disease is caused by a vit D deficiency in children?
Rickets
What is the name for a prolonged vit. D deficiency in adults?
Osteomalacia
What type of osteoporosis is found only in women and is due to low estrogen?
Post menopausal osteoporosis
What type of osteoporosis is found equally on men and womenand is a result of decreased HGH levels?
Age related osteoporosis
What do each of these things have in common?
- Long use of glucocorticoids 4. Excessive thyroid hormones
- Antacid use – w/Al 5. Anticonvulsants
- High protein diet 6. other drugs
Each on often leads to osteoporosis
What are the three steps to osteoporosis prevention?
- Balanced diet
- Weight bearing exercise
- Healthy lifestyle
