bones and cartilage Flashcards
bone composition w/o water
organic matter (carbon containing compounds - carbohydrates, protiens, lipids, nucleic acids) inorganic matter (minerals aka ash)
how much of bone is organic tissue
33%, comprised of fibrous tissues + cells
fibrous tissues:
- collagen
-protien and carbohydrate
chondroitin sulfate purpose in bones
provides resistance to compression in day to day activities - sometimes taken to combat osteoarthritis.
role of organic tissue in bone
provides resilience, toughness and flexibility
- ability to return to go form.
inorganic salts in bone
make up 67% dry matter - 80% CaP - 20% CaCO3 and magnesium phosphate - lots of Ca, 1cc/g 99% body Ca in bones and teeth
functions of salts and minerals in bone
- Hardness
- Rigidity
- Resistance to x-rays
decalcification of bone
done by applying acid treatment. would result in all rigidity being eliminated making bone flexible
what would happen if all organic tissue was removed from bone?
removes all of the framework so it would literally turn into dust.
how much of bone is water?
25%
bone mineral primary constituents and their ratio
Ca:P in a 2:1 ratio
compositon of entire bone (w water)
25% water
~45% mineral content
30% organic matter
what major organs does the skull protect?
brain, eyes and ears.
protective functions of bone
- skull
- vertebral column for spinal cord
- rib cage for heart and lungs
- pelvis for repro, bladder and some of digestive tract
functions of bone
protective gives the body structure acts as a lever for locomotion mineral storage blood formation
osteoblasts
synthesize bone
produces bone matrix
produces collagen and ground stubstance
calcification of matrix
when osteoblasts synthesize bone, what do they do?
- soft flexible matrix of organic tissue secreted made of collagen fibres and polysaccharides and protien (called GAGS) aka osteoid
- harden the matrix via ossification
- get trapped in the ossified matrix to make osteocytes
canaliculi
tubes that supply blood to osteocytes via development of cytoplasmic extensions
cancellous bone
aka spongy
central part w spaces filled w marrow and blood vessels. deals w muscles, gravity and other bones.
found on the ends of long bones. contains the red marrow which makes blood for animal.
cancellous bone characteristics
spongy, lightweight, very strong. has red marrow
age effect on red marrow
in compact bone, present in young but converted to yellow as ages.
what is the primary source to synthesize blood cells?
rib+sternum marrow
compact bone characteristics
heavy, dense, strong
compact bone
outside layer of all bones, shafts of long bones. many tiny compacted cylinders of bone, each cylinder contains central canal containing blood vessels, lymphatic and nerves. ossified bone matrix forms the tube/cylinder
lamellae
ossified bone matrix/bone., support system and cells involved
Haversian or osteonal systems
tight compact cylinders of bone, made of central canal that contains blood vessels, lymph vessels, and nerves. contacts each other via canaliculi for nutrient and waste exchange
components of long bone
epiphysis diaphysis epiphyseal plate/physis articular cartilage endosteum periosteum
epiphysis
located on extremities. made of spongy bone, provides lightness and strength. shock absorbers and levers. covered in compact bone covering the whole bone.
diaphysis
aka shaft
contains marrow or medullary cavity. covered in compact bone, where bone can increase in diameter
epiphyseal plate/physis
aka growth plate. cartilage between ends and long bone. where bones increase in length, prone to breaking
articular cartilage
on surface of compact bone where it contacts there bones to make a joint.
made of hyaline cartilage. reduces friction and wear/tear in joints
endosteum
membrane that lines the surfaces surrounding or facing medullary cavity - can make or destroy bones.
made of connective tissue
involved in bone growth, repair, and remodeling
periosteum
covers all bones, outer layer made of CT like collagen
inner layer w osteoblasts
synthesizes and secretes organic matrix.
needed in all ages of animals ppl
periosteum function
increase shaft and diameter, heal fractures/ bone breaks
red marrow
common in the young
in limited areas in older animals
blood forming
yellow marrow
hard and fatty stores fat no blood forming capabilities most common type can revert back to red
osteocytes
mature bone cell, maintains bone matrix, can be recruited for osteoblasts
osteoclasts
large and motile cells
from stem cells in marrow and spleen, breaks down bone. cells present for normal bone turnover and repairing breaks and fractures.
long bones
longer than wide
grows from the ends
many limb bones (humerus, radius, ulna, tibia etc
long bone functions
levers
support weight
locomotion/movement
prehension
short bone
cubic shape, no marrow cavity.
many movements, shock absorption required. like hands and feet
flat bones
thin and expanded in 2 dimensions
- protects vital organs, inc skull bones, ribs, frontal bone, nasal bone
sesamoid bones
like a sesame seed, protects tendons, like the patella
irregular bones
unpaired bones, have complex shape, work for protection, support and muscle attachment
like vertabrae and skull bones
cartilage function
forms attachments w bones, inserted between joint surfaces of bones
supporting framework for soft structures
v important for rest tract
starting point for bone synthesis
cartilage synthesis
done by chondrocytes derived from mesenchyme (undergo mitosis and matrix formation)
hyaline cartilage
glassy appearance
found in joint surfaces, smooth surfaces, costal cartilage
elastic cartilage
shape, structure, and flexibility.
yellow in colour. inner ear, epiglottis, larynx.
fibro cartilage
semielastic cushion of strength in intervertebral discs of the spine
also in ligaments and knee joint and pelvic bones
strongest cartilage
how does cartilage differ from bone
softness- softer
more flexible and resilient than bone
bone is better at regenerating
ossification or osteogenesis
bone formation, no effect on structure, similar basis in mechanism, deposited tissue gets calcified,
heteroplastic bone formation
non-skeletal sites, aka visceral skeleton
- os penis to aid mating
- os cordis to support heart valves
- os rostri - in pigs to strengthen noses for rooting behaviour
intramembranosus ossification
synthesis of membrane bone - simple and direct method. no cartilage involved at all
enochondral ossification
develops from cartilage template - in utero
major method for bone formation
postnatal growth
adding bone to outer surface, increases size of medullary cavity bc of osteoclasts.
bone at full size - plate gets ossified, no more cartilage.
capacity to remodel bone
bone remodelling effect of stress on bones
decreases muscle mass, also decreases mobility. an increase in muscle mass increases bone mass
what is bone remodeling
turnover of bone structure, bone is a dynamic living tissue
when blood serum is low what happens
parathyroid hormone increases he release of Ca salts from bones
parathyroid hormone action on osteoclasts, osteoblasts, and osteocytes
Osteoclasts ? - incresae
Osteoblasts ?- decrease
Osteocytes ?- increase
