A&P1 Chapter 7 Lecture 2 Flashcards
What types of cells can osteogenic cells become
Chondroblasts, osteoblasts
What do osteogenic cells come from
Embryonic mesenchyme
Where are osteogenic cells found
Endosteum and inner cellular layer of periosteum
What type of bone cell can osteogenic cells not give rise to
Osteoclasts
Can osteoblasts do mitosis
No
what is the usual shape of osteoblasts
Cuboidal or angular
Where are osteoblasts found
Single layer on the surface of bone, just below the peri or endosteum
What is the first thing secreted by osteoblasts
Soft matrix
What organelle produces soft matrix
Endoplasmic Reticulum and the Golgi
What does the soft matrix contain
Precursors of hydroxyapatite
What is hydroxyapatite
Complex form of calcium phosphate
Chief structural element of all vertebrate bone
Hydroxyapatite
Ossification
Formation of bone by osteoblasts, cells surround themselves with matrix (hydroxyapatite), matrix hardens
How do osteocytes communicate with each other and exchange materials
Processes connecting them with gap junctions
Osteocytes
Mature bone cells, osteoblasts trapped in matrix
Spaces where the osteocyte cell body is
Lacunae
Spaces through which osteocyte processes pass
Canaliculi
Functions of osteocytes
- Resorb or deposit matrix
- Homeostatic density of calcium and phosphate
- Stress sensors
How do osteocytes act as stress sensors
When force is applied, extracellular and intracellular fluid flows through the processes and allows remodeling of changes
Osteoclasts
Bone dissolving cells on the bone surfaces
What is the characteristic feature of the shape of osteoclasts
Ruffled border
Where can osteoclasts be found
cellular layer of the periosteum, sometimes endosteum
Where do osteoclasts come from
stem cells in bone marrow, monocytes
What are monocytes
white blood cells that develop when they have multiple stem cells fused together
What is the function of the ruffled border of osteoclasts
Increase surface area, enhance efficiency of bone resorption
What do osteoclasts contain that breaks down bone tissue
Packets of hydrogen ions and enzymes that when released form an acid
Fractions of organic and inorganic components of matrix
1/3 organic, 2/3 inorganic
What is the organic component of matrix made by
Osteoblasts
What does the organic component of the matrix contain
Collagen, elastin, other protein-carbohydrate complexes
What does the inorganic component of the matrix contain
Hydroxyapatite, calcium carbonate
What is the function of the hydroxyapatite and calcium carbonate in bone
Give bones structure and flexibility
