Group 8/7/19 Flashcards
Learning issues
Learning issues:
- Anatomy of forearm (elbow to knuckles, bones, muscles, tendons, ligaments)
- Bones (structure, development, healing)
lateral epicondylitis cause and sign*
- cause: overuse of muscles that attach to the lateral epicondyle, called “tennis elbow. Microtears of the proximal attachment of the extensor muscles
- sign: pain over lateral epicondyle
medial epicondylitis cause and sign*
- similar to lateral, but at medial epicondyle
- called “golfer’s elbow”
anatomical snuffbox: appearance and composition involved*
- triangular depression of posterolateral wrist
- formed by abductor pollicis longus, extensor pollicis brevis, and extensor pollicis longus tendons
which bones develop from intramembraneous ossification vs. endochondral ossification*
- intramembraneous develops bones of calvarium, facial bones, and clavicle
- endochondral ossification develops bones of axial skeleton, appendicular skeleton, and base of skull
major difference between long vs. short bone growth
- long bones go through endochondral ossification and develop a primary and secondary ossification center
- short bones only develop a primary ossification center (except for the calcaneus, has secondary)
major structural parts of the long bone
- epiphyses are the swollen ends of bone
- diaphysis is the middle, shaft part
- compact bone envelopes
- spongy bone inside the swollen ends
- medullary cavity within the shaft
synostosis
process by which diaphysis fuses with epiphysis during long bone growth, stops the growth of the bone
bone matrix structure and function
- matrix has mineral calcium phosphate in the form of hydroxyapatite crystals, type 1 collagen, and other noncollagenous proteins
- makes it a hard tissue that provides support and protection
lacunae
spaces within the bone matrix
osteocyte, definition and location
- the mature bone cell enclosed by bone matrix that was previously secreted as an osteoblast
- located within the lacunae and canaliculi
canaliculi
tunnels within the mineralized matrix of bone that connect adjacent lacunae and allow contact between neighboring osteocytes
osteoprogenitor cells
derived from mesenchymal stem cells in the bone marrow, give rise to osteoblasts
osteoblasts: what are they, what do they differentiate from, what are measurers of their activity*
- cells that build bone by secreting type 1 collagen and catalyzing mineralization in alkaline environment via ALP (an enzyme), they make extracellular matrix of bone.
- differentiate from mesenchymal cells in the periosteum
- osteoblastic activity is measured by bone ALP, osteocalcin, propeptides of type 1 procollagen
osteoclasts function and origin*
- Dissolves (“crushes”) bones by secreting H+ and collagenases, resorbs bone
- Differentiates from fusion of monocyte/macrophage lineage precursors.
- Markedly acidophilic
types of bone
compact (dense) or spongy (cancellous)
compact bone
compact, dense layer that forms the outside of the bone
spongy bone
sponge-like meshwork that has trabeculae and forms the interior of the bone
periosteum
a sheath of dense fibrous connective tissue that covers the bone, except in areas where bones touch each other
contains osteoprogenitor cells
endosteum
- the lining tissue of the compact bone that faces the marrow cavity and the trabeculae of the spongy bone within the cavity
- contains osteoprogenitor cells that differentiate into osteoblasts
red bone marrow
contains blood cells and reticular cells and fibers that support the developing blood cells and vessels
yellow marrow
located in the marrow cavity, more common in adults
contains fat cells
osteon
mature bone is composed of cylindrical structural units called osteons (Haversian systems)
lamellae
circles within the osteon that surround the Haversian canal
Haversian canal
longitudinal canals at the center of the osteon that contains the vascular and nerve supply of the osteon
lamellar bone
another name for mature bone
perforating (Volkmann) canals
- span the lamellar bone horizontally
- allows blood vessels and nerves to travel between endosteal and periosteal surfaces
nutrient foramina
- openings in the bone through which blood vessels pass to reach the marrow
- arteries will use these to enter the marrow cavity and provide blood to bone shafts
nutrient arteries
- come from the periosteal buds during development
- supply diaphysis and epiphysis with blood
what is the major difference between endochondral and membranous ossification?*
- in endochondral ossification, a cartilaginous model of bone is first made by chondrocytes. Then osteoclasts and osteblasts replace the model with woven bone, which is remodeled to lamellar bone
- in membranous ossification, woven bone is formed directly without cartilage. Later, it’s remodeled to lamellar bone.
what will stimulate vs. inhibit osteoclast activity?*
- RANKL (RANK ligand that is secreted by osteoblasts) will stimulate RANK receptors on the osteoclasts.
- RANK receptors can be blocked by OPG (osteoprotegerin, a RANKL decoy receptor), to decrease osteoclast activity