Lecture 2 & 3 - Bone Biology Flashcards
list the important essential components of the skeleton
Mechanical component
- > it protects (soft tissue and organs)
- > anchors (ligaments)
- > rigid levers for movement
Physiological production center
- > blood cells
- > storage facilities for fat calcium
ITS NOT STATIC SCAFFOLDING OF THE BODY, IT’S ALWAYS ADAPTING AND CHANGING
the skeleton makes up what percentage of your total body weight
20%
what are the four factors of skeletal variation?
- > ontogeny (growth)
- > sexual dimorphism (xx vx xy)
- > geography (based on how population have adapted to their location/climate)
- > idiosyncratic (usually extra foramens/notches)
explain Wolff’s Law
BONE IS DEPOSITED WHERE IT IS NEEDED AND RESORBED WHERE IT IS NOT NEEDED (use it or lose it)
- > 1869 Julius wold
- > bones are living highly vascularized structures that can change shape over time (remodel)
- > see slide 2 for graph
liste the components of the MSK system and what they do/what they are
Joints
- > connections between different skeletal elements (articulation)
Cartilage
- > dense and elastic compressible connective tissue
Ligaments
- > bone to bone, stabilizing
Tendons
- > muscle to bone, movement of the joint
disarticulation vs articulation
disarticulation means separated and articulated means together
list the three main joint types
Synovial joints
- > mobile
Cartilaginous joints
- > semi-mobile
Fibrous/Syndesmoses Joints
- > immobile
list the types of synovial joints
- > pivot joint
- > ball and socket
- > hinge joint
- > sellar joint
- > planar joint
components of a synovial joint
- > hyaline cartilage
- > synovial fluid
- > joint capsule
types of cartilagenous joints
synchondroses
- > articulating bones that are joined by cartilage
symphysis
- > cartilaginous joint with hyaline cartilage
what are synchondroses
CARTILAGINOUS JOINTS
- > articulating bones that are joined by carlitage
- > have very little movement
- > temporary between growth centers, some persist into adult hood
- > i.e. ribs to sternum
what are symphysis
- > type of cartilaginous joint with hyaline cartilage
i.e. pubic symphysis
what are fibrous/syndesmoses joints
- > tight inflexible joints
- > bones joined by bands of dense fibrous, tissue in the form of membrane or ligaments
i.e. distal tibial connected to fibula or cranial sutures
ratio of bone’s inorganic vs organic material
- > 90% organic (collagen)
- > 10% inorganic (hydroxyapatite)
what do hydroxyapatite and collagen do/provide in reference to bone
- > H give bone the rigidity
- > C gives us the flexibility
list the different bone classifications (shape)
- > long
- > short
- > flat
- > irregular
- > sesamoid
list some examples of long bones
LONGER THAN WIDE
- > femur, humerus, fibula, tibia, ulna
list some examples of short bone
AS WIDE AS THEY ARE LONG
- > carpals, tarsals
list some examples of flat bones
STRONG FLAT PROTECTIVE
- > scapula, sternum, cranium, os coxae, ribs
list some examples of irregular bones
- > vertebrae, sacrum, mandible
list some examples of sesamoid bones
PROTECTS TENDONS
- > patella, pisiform (sometimes people have extra sesamoids in hands and feet)
what are the difference sections of a long bone
- > 2 epiphyses on either end
- > 2 metaphyses, which house the growth plate
- > diaphysis, long section of the bone
- > medullary cavity, housed in the diaphysis
list the different bone types (age & structure)
SEE SL. 24 TO SEE GRAPH
AGE
- > woven (immature)
- > lamellar (mature)
STRUCTURE (types of lamellar bone)
- > cortical/compact
- > cancellous/spongy/trabecular
ALL MATURE BONES ARE LAMELLAR BUT WOVEN MATURES TO LAMELLAR BONE
how does the proportion of red/yellow bone marrow change as we age, why?
we start out with exclusively red marrow as infants (0-1yrs) then red marrow is converted into yellow marrow during childhood and into adolescence (1-20)
- > conversion begins at the centers of the long bone and extends axially and peripherally
- > red marrow makes blood cells, time of rapid growth needs more and more blood
list the main bone cells and what they do
ALL OF THESE CELLS ARE FOUND IN OSTEOGENIC TISSUES
osteoblasts
- > bone formation
osteoclasts
- > bone destruction/resorption
osteocytes
- > bone maintenance
- > signal the appropriate cell type (osteoblasts/clasts) depending on the needs of the body/bone
what are osteogenic tissues and where are they
periosteum
- > a sheath/membrane that covers the whole bone (not joint/articulation point
endosteum
- > lines the inside of the medullary cavity
list all the structures/transport systems found in the bone that allow for nutruient and resource transport
- > haversian canals
- > volkmans canals
- > lacunae
- > canaliculi
which structures allow for horizontal and vertical transport across the bone
Haversian canals
- > allow for the transport of nutrients VERTICALLY across the bone (freeway)
Volkman’s canals
- > allow for the transport of nutrients HORIZONTALLY (off ramps)
Canaliculi
- > the smaller branches off of the volkmans canals, also help with communication
what is a lacunae
are pockets where osteocytes are found
- > osteoblasts lay down bone then trap themselves then they convert into osteocytes
what is an osteon (primary vs secondary)
osteon
- > functional unit of cortical bone
- > primary and secondary mean the same thing, secondary is just laid on top of primary
* this is a good way to tell age as we can see how many secondary osteons are laid down
what are the different types of bone development
intramembranous ossification
- > mineralization of vascular membrane
- > primarily occurs before birth, create the bone/bone blueprint within the membrane
Endochondral ossification
- > bones are preceded by cartilage models
- > nutrient artery
- > buids upon previous previously made cartilage models, occurs after birth
- > diaphysis is created first (primary ossification center) and usually are created in the womb but epiphyses (secondary ossification centers) form after birth
*consider babies bones aren’t fully formed at birth
list both types of directional growth
- > linear growth
- > appositional growth
linear growth
growth plates, which are organized regions of rapid growth, contribute to an increase of bone length
appositional growth
- > increases in bone size/width after endochondral growth has begun
