Lesson 8 Flashcards
skeletal system
composed of bones, cartilages, and ligaments joined to form a framework for the body
osteology
study of bone
how many major bones are in the human body?
206
_____ is the forerunner of most bones and covers joint surfaces
cartilage
_____ hold bones together at joint
ligaments
_____ attach muscle to bone
tendons
roles of the skeleton (6)
- support
- movement
- protection
- electrolyte and acid-base balance
- blood formation
- hormone secretion
osseous tissue
connective tissue with the matrix hardened by calcium phosphate and other minerals
mineralization/calcification
the hardening process of bone
flat bones
thin, curved plates; protect soft organs
examples of flat bones (5)
parietal bones of the skull, sternum, scapula, ribs, hip bones
long bones
longer than wide; rigid levers acted upon by muscles; crucial for movement
examples of long bones (9)
humerus, radius, ulna, femur, tibia, fibula, metacarpals, metatarsals, phalanges
short bones
approximately equal in length and width
examples of short bones (2)
bones of the wrists and ankles
irregular bones
elaborate shapes
examples of irregular bones
vertebrae and some skull bones
what do depressions, groves, and tunnels indicated along the bone surface?
where blood vessels and nerves run along side the bone of enter bone
what do elevations or projections indicate on bone?
where tendons and ligaments attach onto bone; where joints occur with bone
compact bone
dense outer shell of bone; enclosed the marrow (medullary) cavity containing yellow marrow
spongy bone
loosely organized bone tissue found in the ends and center of long bones and in the middle of nearly all others
skeleton is _____ compact and ____ spongy bone by weight
3/4, 1/4
diaphysis
shaft that provides leverage
epiphysis
enlarged end of a long bone; strengthen join and anchor ligaments and tendons
epiphyseal line
remnant of childhood growth zone; epiphyseal plate (composed of cartilage)
articular cartilage
layer of hyaline cartilage that covers joint surfaces; allows joint to move more freely
periosteum
external sheath covering most of bone
perforating fibers
of the periosteum; penetrate underlying bone matrix
outer fibrous layer of _____ and inner osteogenic layer of _____ _____ _____
collagen, bone-forming cells
functions of the periosteum (3)
- isolate bone
- provide route for blood vessels and nerves
- participates in bone growth and repair
endosteum
thin layer of reticular connective tissue lining marrow cavity and all internal bone surfaces
functions of the endosteum (5)
- is an incomplete cellular layer (not a continuous sheet)
- covers the trabeculae of spongy bone
- lines the central canals of osteons
- contains osteogenic cells, osteoblasts, and osteoclasts
- active in bone growth/repair
diploe
inner and outer tables of compact bone enclosing layer of spongy bone in between
osteogenic/osteoprogenitor cells
mesenchymal stem cells found in endosteum and inner layer of periosteum
osteoblasts
bone-forming cells in endosteum and inner layer of periosteum
osteogenesis
synthesize soft organic matter of matrix and promote its mineralization
_____ stimulates osteogenic cells to multiply rapidly and increase the number of osteoblasts which reinforce bone.
stress
osteocyte
former osteoblasts that have become trapped in the matrix they deposited
lacunae
tiny cavities where osteocytes reside
canaliculi
little channels that connect lacunae
_____ _____ allow for passage of nutrients, wastes, and signals between osteocytes
gap junctions
osteocytes do two things…
- deposit matrix
- absorb matrix
how do osteocytes act as strain sensors?
when they’re stressed, they produce biochemical signals that regulate bone remodeling
osteocalcin
part of body’s acute stress response, increases insulin sensitivity, promotes energy availability
osteoclasts
bone-dissolving cells found on the bone surface
osteolysis
the breakdown of bone as part of bone remodeling; important in releasing calcium and phosphate into body fluid
what type of cells do not form from osteogenic cells?
osteoclasts; they develop from the same bone marrow stem cells that give rise to macrophages
by dry weight, bone averages _____ organic and _____ inorganic matter
1/3, 2/3
organic matter of the bone matrix consists of…
collagen and carbohydrate-protein complexes
inorganic matter of the bone matrix consists of…
85% hydroxyapatite
10% calcium carbonate
inorganic ions such as Mg, fluoride, and sodium
Rickets (disease)
caused by mineral deficiency and resulting in soft, deformed bones; not enough calcium from diet (could also be caused by not enough UV light for vitamin D3 synthesis)
collagen molecules contain _____ _____ that break under stress and dissipate shock under load
sacrificial bonds
brittle bone disease
osteogenesis imperfecta
- results from a defect in collagen deposition
concentric lamellae
layers of matrix surrounding a central canal running longitudinally
a central canal and its lamellae constitute an _____
osteon
central canals are connected by transverse _____ _____
perforating canals
circumferential lamellae
encircle inner outer region of dense bone
interstitial lamellae
fill irregular regions between osteons
spicules
lattice of bone slivers in spongy bone
trabeculae
lattice of bone plates covered in endosteum in spongy bone
spaces within spongy bone are filled with _____ _____ _____
red bone marrow
bone marrow
soft tissue occupying marrow cavities of long bones and small spaces of spongy bone
myeloid tissue
red bone marrow
- contains multiple tissues including hematopoietic tissue
- in nearly every bone in a child
- in adults, found in skull, vertebrae, ribs, sternum, part of pelvic girdle, and proximal heads of humerus and femur
yellow bone marrow (2)
- adipose tissue, does not produce blood
- can transform back into red bone marrow in the event of chronic anemia
homeostasis (in bones)
bone building and recycling must be balanced
what conditions are because bone breakdown is faster than bone building causing bones to be weaker? (2)
osteopenia and osteoporosis
What type of bone cells build bone?
osteoblasts
What type of bone cells break down bone?
osteoclasts
