BONES Flashcards
1
Q
Summary of Functions
A
- Support - posture
- Movement - as attachment points for muscle
- Protection - of soft tissue
- Storage - of both minerals and fat
- Hematopoiesis - production of RBCs, WBCs, and PLTs
2
Q
As a characteristic of CT, bone is composed of
A
- cells and abundant matrix
- Bone tissue on the whole is innervated, contains lymphatics, and is highly vascular
3
Q
Bone Matrix includes:
A
- protein scaffolding (mostly collagen) arranged in alternating layers (at 90 degrees to one another),
- deposited minerals (mostly Ca, P in the form of hydroxyapatite),
- cells referred to as osteocytes
4
Q
The composition matrix determines
A
- strength of bone
5
Q
Proteins provide _____ strength
Minerals provide _____ strength
A
- TENSILE (proteins)
- COMPRESSION (minerals)
6
Q
Osteoblasts
What are the 3 basic stages of existence?
What are these stages termed?
A
- bone-forming cells
- produce protein fibers for the matrix
- secrete enzymes that promote mineralization of the matrix
- once engulfed in the calcified matrix, they stop the above and become known as osteocytes
* * stages termed OSSIFICATION*
7
Q
Osteocytes
A
- thought to be mechanosensors within bone, sensing tensile and compressive stress
- no longer bone-forming cells
- remain connected and communicate with the osteoblasts
8
Q
Osteoclasts
A
- digest and remove excess (old) and damaged bone
- process is known as resorption and involves acid and enzyme secretion (think phagocytosis as this type of cell is a specialized macrophage)
9
Q
All individual bone has 2 distinct areas of varying matrix density:
Compact Bone
Cancellous Bone
A
- makes up the surface of all bone and the shaft of long bones
- this is where one will find bundles of collagen fibers stacked in alternating layers and tightly packed in concentric rings around a vessel-containing canal, collectively termed haversian systems. Intercellular communication/transport occurs in both the longitudinal and transverse directions. Columns.
10
Q
All individual bone has 2 distinct areas of varying matrix density:
Compact Bone
Cancellous Bone
A
- makes up the bulk of short, flat, and irregular bone, as well as the ends of the long bone
- it also lines the medullary cavity of long bone
- this is the more porous, marrow containing matrix
- aka - spongey bone, trabecular bone
11
Q
Marrow
A
- aka myeloid tissue, always co-exists with cancellous bone
- considered a type of CT, and occurs in 2 somewhat interchangeable forms based on preponderance of cell type
RED MARROW & YELLOW MARROW
12
Q
Red Marrow
A
- consists mainly of hematopoietic stem cells, and relative little fat
- site of RBC, WBC, and PLT production
- found at ends of long bone and center of other bone (but mainly flat bones)
13
Q
Yellow Marrow
A
- consists mostly of fat cells (yellow tissue)
- site for adipose storage
- found in central (medullary) cavity of long bone
14
Q
Endosteum
A
- thin CT lining the medullary cavity
- contains osteoblasts from the marrow
15
Q
Periosteum
A
- dense CT covering the outer bone surface
- contians stem cells that can differentiate into osteoblasts and chondroblasts (cartilage forming cells)
- contains nocireceptors (sensory neurons)
