Bone/Cartilage Flashcards
is cartilage avascular or vascular
avascular
what percent is cartilage composed of water?
80%
are there nerves in cartilage
no nerves
three types of cartilage and roles/locations
hyaline:
—role: support, flexibility, resilience (weakest, most widespread)
—loc: articular surfaces, costals, respiratory (trachea/larynx), nasal
Fibro:
—role: compressible, high pressure, stretch (strongest)
—loc: intervertebral disks
—no perichondrium
—both type 1 and 2 collagen
elastic:
—role: elasticity and maintain shape
—loc: external ear, nasal tip, eustachian tube, epiglottis
—type 2 collagen and elastin
cartilage cells
chondroblasts: immature/undiff cells
chondrocytes: mature cells (lacunae enclosure)
ground substance of cartilage
proteoglycans (chondroitin sulfates/hyaluronic acid/electrostatic repulsion)
what are the components of cartilage
cells, ground substance, collagen
perichondrium
dense irregular ct that envelopes elastic and hyaline cartilage (not fibrocart)
general bone functions
support/shape
protection
assist homeostasis
blood cell production
is bone vascular or avascular
vascular
compact vs spongey bone
cortical/compact:
— outer layer of bone
—dense
—osteons
—80% of bone
cancellous/spongey:
—inner layer
—trabeculae
bone remodeling cells
osteoclast: resorb bone
osteoblast:build bone
hydroxyapatite comp
39% calcium
18% phosphorous
where is 99% of calcium sored in the body?
bone
calcium homeostasis hormones
parathyroid hormone (PTH)
calcitonin
“activated” Vit D
PTH does what when calcium blood levels are too low
stimulates Ca release from bone
increase Ca absorption from gut
promotes Vit D act
calcitonin does what when calcium blood levels get too high
reabsorption of calcium from bone
osteomalacia/rickets
defective bone matric calcification due to Vit D deficiency (and/or Ca deficiency)
osteopetrosis
impaired osteoclasts (fragile bone)
osteoporosis
excess osteoclast function
Tx: biphosphonates, teriparatide (bone-building drug)
Biphosphonate-associated osteonecrosis of the jaw
biphosphonate therapy for osteoporosis: disfiguring jaw conditions involving serious infection and abnormal build-up of bone
what tissue is composed of 80% water, avascular, no nerve fibers, and flexible?
cartilage