Bone Physiology Flashcards
What are the components of the skeletal system?
- Bones
- Cartilage
- Joints
- Ligaments
- Connective tissues
State the characteristic of flat bones?
Internal/external table
Separated by dipole
Provides protection of organs
State the characteristic of long bones?
Longer than they are wide.
Useful for leverage.
State the characteristic of short bones?
Same width as their length.
Allows subtle movement.
Transfers forces between bones.
State the characteristic of irregular bones?
Complex shapes/functions.
Projections to increase SA.
Useful for protection.
State where sutural bones are located within the body.
Between skull bone.
Where do sesamoid bones form?
In tendon, arise from forces in tendons via ossification.
What is the role of then diaphysis?
Medullary cavity - holds the bone marrow.
Hollow cylinder - reduces weight.
More sturdy than compact bone.
What type of bone can you find in the epiphysis?
Trabecular bone
The epiphysis has projections that allow for what?
Projections allow for articulations at joint.
What is the function of articular (hyaline) cartilage?
Covers ends of bone for protection.
What is the name of the structural unit of bone tissue?
Osteon.
What components make up osseous tissue? State their ratios.
- Ground substance (2/3 bone matrix).
- Protein (1/3 bone matrix).
- Bone cells
State the journey of mesenchymal stem cells maturing into mature bone cells.
Mesenchymal stem cells -> Osteoblasts -> Osteocytes
What is the role of osteoclasts?
Have enzymes which destroy old bone, multi-nucleated, large SA.
Reduced activity of osteoclasts leads what?
Increased bone density, decreased bone reabsorption.
What is an osteoid?
Immature bone, no minerals.
What is canaliculi?
Cytoplasmic extensions which allow for communication and transfer minerals from neighbouring osteocytes.
TRUE OR FALSE:
Trabecular bone have osteons.
False - trabecular bone does not have osteons.
Trabeculae has cross fibres which ensures what?
Strength in many direction.
State the functions of red and yellow bone marrow.
- Red - provides nutrients to osteocytes.
2. Yellow - stores adipose tissue.
Which of the two types of bone (compact/trabecular) have a blood supply?
Compact bone.
What is the periosteum? State the two layers it is composed of.
Membrane on the outside of the bone.
- Outer fibrous layer
- Inner cellular layer
What is the endosteum? Where does it line?
Membrane lining inside of bone - lines medullary cavity, central canals, and trabeculae.
Intramembrane ossification forms what type of bone?
Flat bone formation
Endochondrial ossification is the formation of bone from what?
Cartilage
Define appositional growth.
Growth in width - bone deposited by osteoblasts and reabsorbed by osteoclasts.
Intramembrane ossification forms spincules which are what?
Lumps of bone.
What happens to chondrocytes within calcifying matrix?
Enlarge and die.
The penetration of blood vessels/osteoblasts penetrate inside the bone to produce bone is know as what?
Primary Ossification Centre = diaphysis
Where does the secondary ossification centre form?
Epiphysis
The enlargement of the primary ossification centre forms what?
Medullary cavity.
How does the epiphyseal line form?
Fusion of bone when cartilage (growth plate) turns to bone.
What are the four requirements for bone growth?
Minerals
Vitamins
Hormones
Loading/applied force
What is the functions of osteoclasts and osteoblasts in bone remodelling?
Osteoclasts reabsorb bone
Osteoblast form bone
What type of bone cells detect forces in bone?
Osteocytes - adaption of loading.
How are calcium levels maintained in bone remodelling?
Hormones control storage of calcium -> PTH stimulates bone resorption to release calcium -> calcitonin stimulates bones formation to store calcium.
New osteons have less minerals and appear darker, where are they more apparent?
Periosteal surface.
What colour do mineralised osteons appear under a microscope?
White.
Peak bone mineral density occurs at how many years old?
30
Women will rapidly loose their bone mineral density after what?
Menopause
Describe the process of fracture repair?
- Bleeding, formation of clot.
- Formation of external/internal callus.
- Osteoblasts break down fragments of bone.
- External callus replaced by compact bone.
- Internal callus unites broken ends.
- Internal swelling causes remodelling.
