BS: The Gross Structure Flashcards
Bone structure has three levels:
- gross
- microscopic
- chemical
Dense outside layer […] surrounds the inside […].
compact; spongy
Internal to the spongy bone (also known as trabecular bone) lies…
trabeculae– honeycomb of small flat pieces
What is in between trabeculae?
red or yellow marrow
For flat bones […] bone sandwiches […].
spongy; compact
Which bones share a simple pattern?
- short
- irregular
- flat
What are the 4 parts of the simple pattern short/irregular/flat bones?
- sif bones
compact bone covers spongy
spongy contains bone marrow between trabeculae but no defined cavity
bone is covered in and out by connective tissue membranes
joints covered by hyaline cartilage
Thin plates of spongy bone also known as…
diploe
The connective tissue membranes of sif bones?
periosteum (outside) and endosteum (inside)
LB: What is the general structure of long bones?
a shaft, bone ends, and membranes
LB: A tubular […], also known as the shaft, forms the long […] of the bone.
diaphysis; axis
LB: The thick collar of […] bone surrounds a central […] cavity or […] cavity.
compact; medullary; marrow
LB: What are the bone ends?
epiphyses
LB: What forms the epiphyses?
compact bone extension (exterior)
spongy bone (interior)
LB: What covers the surface of the epiphyses?
thin layer of articular/hyaline cartilage
LB: What is the purpose of the articular/hyaline covering?
cushioning during movement and absorbing stress
LB: Between the diaphysis and each epiphysis is an […] line.
epiphyseal
LB: The epiphyseal plate is located…
at the junction of the epiphyseal and diaphysis
LB: The epiphyseal plate ([…] plate), is a disc of […] cartilage that grows during childhood.
growth; hyaline
LB: The flared middle portion of the bone where the diaphysis and epiphysis meet
metaphysis
LB: Periosteum covers the […] surface EXCEPT the […] surfaces.
external; joint
LB: The periosteum/endosteum has two layers:
fibrous (outer)
osteogenic (inner)
LB: The fibrous outer layer of the periosteum is […] connective tissue.
dense
LB: The inner periosteum layer contains what type of cells?
osteoprogenitor cells (osteogenic)
osteoclasts
osteoblasts
LB: What are the osteoprogenitor cells?
primitive stem cells give rise to most bone cells
LB: Why are broken bones so painful?
The periosteum is richly supplied with nerve fibers and blood vessels
LB: The periosteum also provides […] points for tendons/ligaments.
anchoring
LB: What are perforating fibers? Where can you find them?
bundles of collagen fibers that secure the layer to the bone by extending to the matrix
in the periosteum layer
perforating: pierce/make holes
LB: The endosteum covers […] bone surface both spongy and compact.
internal
LB: What cells are within the endosteum?
the same as the periosteum
What are the main vessels serving the diaphysis?
nutrient artery and nutrient vein
Where do the blood vessels and nerves run through?
nutrient foramen– an opening in the diaphysis wall
Pathway of blood and nerve vessels:
diaphysis—nutrient foramen—bone marrow/spongy bone—branches to compact
Red marrow also known as…
hematopoietic (blood forming tissue)
Where do children house red marrow?
the medullary cavity of the diaphysis and all areas of spongy bone
Where do adults house red marrow?
small amount in between trabeculae
Why is there little red marrow within the long bones of an adult?
most of it has been replaced by yellow marrow
In which bones can you find red marrow?
LB: femur and humerus
FB: skull, sternum, ribs, clavicles, scapulae
IB: hip bones and vertebrae
How can an adult revert to red marrow?
if they become anemic
Bone marking can fit into 3 categories:
- projections
- surfaces
- depressions/opening
Projections:
site of muscle and ligament attachment
Surfaces:
form joints
Depressions/openings:
for blood/nerve vessels
What are the 5 major cell types:
- osteoprogenitor
- osteoblasts
- osteoclasts
- bone lining cells
- osteocytes
All of these except for the […] originate from embryonic connective tissue cells.
osteoclasts
What is the process remodeling?
cells continuously resorb and deposit
In growing bones, […] cells are flattened or squamous.
osteogenic
When osteogenic cells are stimulated, some of these cells turn to […].
osteoblasts
Osteoblasts secretions includes:
- collagen (90%)
2. calcium-binding proteins
What do calcium-binding proteins create?
the initial, un-mineralized bone (osteoid)
Matrix calcification is done by […] cells.
osteoblasts
Osteocytes occupy what spaces?
lacunae
What are the 3 function of osteocytes?
maintain and monitor bone matrix
respond to mechanical stimuli
trigger bone remodeling
Osteocyte trigger bone remodeling due to mechanical […] or to maintain […] homeostasis.
stress; calcium
Where can you find bone lining cells?
on surfaces where bone remodeling is not going on
What is the purpose of bone lining cells?
maintain the matrix
Osteoclasts are giant […] cells located at sites of bone […].
multinucleate; resorption
Where are osteoclasts derived from?
WBC lineage that creates macrophages
Osteoclasts lie in a shallow […].
depression
Osteoclasts have a distinct […] border that […] contacts the bone.
ruffled; directly
What is the purpose of the osteoclasts ruffled border?
plasma membrane infoldings increase surface area for enzymatically degrading bones
The structural unit of compact bone is […] which is parallel to the long […] of the bone.
osteon; axis
What is the function of osteons?
tiny weight-bearing pillars
What is the matrix tube of osteons called?
lamella
Osteon’s design as a “twister resister” is due to what?
collagen fibers running in different directions to withstand torsional stresses
How can collagen fibers within lamella alternate their direction?
tiny crystals of bone lamellae
What is in the core of each osteon?
central canal (Haversian canal)
What does the core of each osteon contain?
small blood vessels and nerve fibers (serve the cells)
Osteon canals of a second type called […] canals or Volkmann’s canals.
perforating
Perforating canals lie at […] angles to the long axis of the bone. They connect […] and […] supply of the […] cavity to central canals.
right; blood vessels; nerve fibers; medullary
Perforating canals are not surrounded by […].
lamellae
Osteocytes occupy […] at the junctions of lamellae.
lacunae
Hairlike canals called […] radiate from the […] connecting them to each other and to the central canal/
canaliculi; lucanae
Osteon = […]
Haversian System
What is the structural unit of compact bone?
osteon
Lamellae:
compact bone matrix consisting of a cylinder with many rings
What contributes to the hardness of bone?
hydroxyapatite– makes 65% of the mass
What are the inorganic components of the bone matrix?
hydroxyapatite
