Musculoskeletal System Flashcards
Diaphysis
shaft of the bone
middle part of bone
Physeal cartilage
“area of bone lengthening”
“Growth plate”
where calcifying cartilage and bone meet. osteoblasts make bone here. and cartilage grows here.
Epiphysis
end of bone
articular cartilage
made of hyaline cartilage
parts of cartilage model that lasts throughout life
bone growth during puberty…
when hormones change, cartilage proliferation slows.
osteoblast and osteoclast don’t slow.
Medullary cavity
intervening spaces of bone. where red and yellow marrow live.
yellow marrow
fat storage.
in adults
Red Marrow
active hematopoiesis (makes RBCs) in young animals
Cortex
dense outer core of bone
Support pieces
Periosteum
connective tissue membrane around the MATURE bone
Endosteum
connective tissue membrane that lines the medullary cavity
Cancellous bone
(spongy or trabecular)
inner meshwork of bone. the internal struts.
[studs of a house]
direction of bone growth in long bone
outward
direction of cartilage growth in long bone (endochondral ossification)
inward
Muscle as an organ
highly specialized to do ONE thing = shorten/attempt to shorten Has tissues (skeletal mm., connective, nervous) has motor unit
Function of muscle as an organ
- myocytes: shorten/attempt to shorten
- produce mvmt of bones and organs
- prevent movement (stabilize jt - the attempt to shorten part)
Motor Unit
neuron and group of associated muscles
functional contractile unit of m.
Precision of muscles determined by…
myocytes/neuron
low ratio: very precise
moderate ration: fine control (in our hands)
high ratio: general power (cranial arm)
origin of muscle
more proximal attachment
tends to be area that doesn’t move
Muscle blood supply
get it to different parts by same general large vessel
Intramembranous ossification
no cartilage model
uses connective tissue membrane and lays down bone under it
flat bones made this way.
Endochondral ossification (general description)
cartilage model
long bones made this way
4 overlapping phases
Phase 1 endochondral ossification
formation of cartilaginous model
- same shape as mature bone - solid rod of hyaline cartilage - perichondrium surrounds most of it - no bone tissue or blood vessels
2nd phase of endochonral ossification
formation of primary center of ossification
Center of ossification
distinct site where bone tissue develops
Osteoprogenitor cells
become osteoblasts, osteoclasts, and osteocytes when blood vessels grow toward it.
Osteoclasts
‘eats’ Ca.
the calcified cartilage and calcified osteoid matrix
Osteoblast
secrete osteoid
‘bone’ + ‘forming’
Osteocytes
driven by hormones.
mature bone cells (not growing anymore. adults primary bone cell type)
Secondary centers of ossification
at least one per long bone.
not all bones have them (aka short bones)
Long Bones
elongated on 1 axis
expanded ends
humurus
Short bones
Cuboidal
Many articular surfaces
bones of carpus and tarsus
Flat Bones
expanded in 2 axes
Scapula, os coxae, ribs
Irregular Bones
numerous projections
vertebrae
Sesamoid bones
embedded (typically in tendons)
protect and redirect
patella, proximal sesamoid bones in manus
Pneumatic Bones
air-filled spaces
mammals’ sinuses, mostly in birds though
Axial skeleton
central axis (median plane) primary job = support and protect skull, vertebral column, ribs
Appendicular Skeleton
primary job = lever for locomotion
limbs (scapula/pelvis down)
Bone functions
- Physical: support, protect, lever for mvmt
2. Metabolic: Ca and P reservoir, fat storage, hematopoiesis (making RBC/WBC)
Bone the tissue
Bone cells (osteoblast, osteoclast, osteocytes) extracellular material (osteoid)
