Anatomy- Bone Histology and Physiology Flashcards
What is bone made out of?
Connective Tissue
What three types of Cells do bones have?
Osteoblasts, Osteoclasts, and Osteocytes
What is the main function of Osteoblasts?
Osteoblasts build bone and they’re immature bone cells
What are 2 traits of Osteocytes?
-Mature bone surrounded by bone matrix
-House in the Lacuna
What are 3 traits of Osteoclasts?
-They’re very large cells
-They’re cells that break down bone
-“blasts build, Clasts Kill”
Why do we need Osteoclasts?
-balance Ph
-Balance blood calcium
-to get rid of old bone
What is the bone matrix made out of?
-Collagen (protein) 30%
-Salts
What strength does collagen provide to a bone?
-provides tensile strength like a rope
What are most of the salts that make up the bone matrix?
Most salts are Calcium salts in the form of Hydroxyapatite
-salts in the bone provide compressive strength to bear body weight
-if you didn’t have salts in the bone it would be flexible
Why would someones bone break?
-insufficient amount of vita D., Leading to rickets
-Calcium Consumption
-Age
-Use it or lose it
What is the difference between cancellous and compact bone?
-Cancellous more spongy, has red bone marrow in it, and has osteoclasts, Osteoblasts, and Osteocytes
Compact more is more organized.
-Osteons
-Central canal (red dot through the middle/blood vessel)
-Interestital lamallae (line outside the Osteon)
-Concentric Lamellae (big circles within the Osteon)
-Canaliculi (Spider leg projections)
What does the Canaliculi do?
-Connects to Osteocytes
-Microscopic
-Contains Fluid
-Communication between osteocytes
What happens during appositional bone growth?
-The bone gets wider
-Occurs in the Diaphysis
-Growth Hormones
-The medullary cavity grows, but compact material does not get thicker
What are some causes of Bone remodeling?
-Injury (fracturing a bone
-Growth (maturing)
-Stress (more bone needed when there’s stress
-Reshaped (spine)
What happens in Osteoclastic activity?
2 ways to break down a bone
-Secretes acid (Dissolves Hydroxyapatite)
-Secretes Proteolytic (kills enzymes and proteins)
Takes 1 year and dissolves collagen
Bone repair/how does a bone heal itself?
4 steps:
-Hematoma formation (blood floods to the injury site)
-Calloused formation(a mass of connective tissue connects to the ends of a broken bone
-Callus densities with cancellous bone?
-Connective to compact (some of the external cells remain)
what are the Ossification process steps?
- Chondrocytes = mitosis
2.Old Chondrocytes will move to the diaphysis side of the growth plate
3.Lacuna grows
4.Calcium salts fill Lacuna - Chondrocytes die
6.Blood vessels grow into the Lacuna
7.Osteoblasts and Clasts work to ossify the bone
8.The growth plate ossifies with hormonal changes
