Lecture 30 - Bone Flashcards
T or F: Bone is the hardest of all connective tissue
T
Bone is a _______ (what is depositited in the ECM?)
connective, dynamic tissue in which the ECM is hardened by deposition of calcium
Bone can mean what 2 things:
- Osseous tissue only
- Organ composed of blood, bone marrow, cartilage, adipose tissue, nervous tissue, and fibrous connective tissue
What are the 5 functions of bone
- Structural Support
- Permit movement
- Protect vital organs
- Hematopoiesis
- Mineral homeostasis
What are the 3 types of cells found in bones and their function
- Osteoblasts: Bone forming cells that are found in the endosteum and periosteum that synthesize bone
- Osteocytes: Mature bone cells that act as mechanosensory receptors to regulate bone response to stress and mechanical load and communicate to osteoblasts and osteoclasts
- Osteoclasts: Found on bone surface and derived from bone marrow that is responsible for bone resorption
Osteoblasts turn into
Osteocytes
What are the 2 components that make up the ECM of bone
- Organic Component: Made of type 1 collagen, glycosaminoglycans and proteoglycans that gives bone flexibility
- Inorganic Component: Deposits crystals of calcium and phosphate that enables bone to support weight of body without sagging
T or F: Bone is a composite (combined of 2 or more materials without dissolving into each other)
T
What are the 2 layers of bone
- Outer layer: compact or cortical bone
- Inner layer: Cancellous, trabecular or spongy bone
What 2 architectures of bone are formed from collagen
- Woven bone: Disorganized network of collagen fibers that make up young bone and is mechanically weak
- Lamellar Bone: Organized collage that forms mature bone and is mechanically strong
Bone Marrow
Soft tissue that occupies the medullary cavity of a long bone and spaces in spongy bone
What are 2 types of bone marrow and their function
- Red Marrow: Found in skull, pelvis, spine, ribs and ends of long bones that perform hemopoiesis and remove old blood cells from circulation
- Yellow Marrow: Found in spongy bones and shafts of long bone that are now inactive to red blood cell formation and mainly made of fat
T or F: Yellow marrow turns into red marrow
F, red marrow turns into yellow marrow as it gets older
Label the missing parts of the long bone (wont be tested but good to know)
Skeleton before birth consists of
cartilage and fibrous structures shaped like bones
Ossification
Formation of bone
What are the 2 methods of ossification
- Intramembranous: Mandible, clavicle, skull
- Endochondral: Rest of skeleton
Bone Modeling
Process where bones change their overall shape in response to physiologic influences or mechanical forces
Wolff’s Law in regards to bone modeling
Long bones change shape to accommodate stresses placed on them
T or F: formation and resorption between osteoblasts and osteoclasts, respectively are not tightly linked in bone modeling
T
Bone remodeling
Renewal of bone by continuous removal of packets of bone by replacing it with proteinaceous matrix and mineralization to maintain bone strength that occurs in cortical and cancellous bone to prevent bone micro-damage
T or F: In bone remodeling, osteoclasts and osteoblasts are tightly linked for bone formation and resorption
T
What are the 4 steps of bone remodeling
- Activation: Osteoclasts
- Resorption: 2-4 weeks
- Reversal: Change from resorption to bone formation
- Formation: 4-6 months to complete
Fracture
Loss of continuity of the bone
What are 3 classification of fractures
- Pattern
- Cause -> traumatic or pathologic
- Body part
Difference between open verses closed fractures
Open/Compound Fractures: Skin is broken and bone protrudes outwards
Closed: Skin is not broken
Difference between displaced versus non-displaced for fractures
Displaced: Bone moved so there is a gap around the fracture
Non-displaced: Bone did not move
What are 2 patterns of bone fractures
- Single straight-line break: Oblique (diagonal to long axis of bone) or transverse (perpendicular to long axis of bone)
- More than a single straight line: Greenstick, comminuted, spiral
Colles vs Smith Fracture