Bone/Cartilage Flashcards

1
Q

is cartilage avascular or vascular

A

avascular

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2
Q

what percent is cartilage composed of water?

A

80%

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3
Q

are there nerves in cartilage

A

no nerves

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4
Q

three types of cartilage and roles/locations

A

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

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5
Q

cartilage cells

A

chondroblasts: immature/undiff cells
chondrocytes: mature cells (lacunae enclosure)

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6
Q

ground substance of cartilage

A

proteoglycans (chondroitin sulfates/hyaluronic acid/electrostatic repulsion)

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7
Q

what are the components of cartilage

A

cells, ground substance, collagen

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8
Q

perichondrium

A

dense irregular ct that envelopes elastic and hyaline cartilage (not fibrocart)

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9
Q

general bone functions

A

support/shape
protection
assist homeostasis
blood cell production

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10
Q

is bone vascular or avascular

A

vascular

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11
Q

compact vs spongey bone

A

cortical/compact:
— outer layer of bone
—dense
—osteons
—80% of bone
cancellous/spongey:
—inner layer
—trabeculae

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12
Q

bone remodeling cells

A

osteoclast: resorb bone
osteoblast:build bone

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13
Q

hydroxyapatite comp

A

39% calcium
18% phosphorous

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14
Q

where is 99% of calcium sored in the body?

A

bone

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15
Q

calcium homeostasis hormones

A

parathyroid hormone (PTH)
calcitonin
“activated” Vit D

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16
Q

PTH does what when calcium blood levels are too low

A

stimulates Ca release from bone
increase Ca absorption from gut
promotes Vit D act

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17
Q

calcitonin does what when calcium blood levels get too high

A

reabsorption of calcium from bone

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18
Q

osteomalacia/rickets

A

defective bone matric calcification due to Vit D deficiency (and/or Ca deficiency)

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19
Q

osteopetrosis

A

impaired osteoclasts (fragile bone)

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20
Q

osteoporosis

A

excess osteoclast function

Tx: biphosphonates, teriparatide (bone-building drug)

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21
Q

Biphosphonate-associated osteonecrosis of the jaw

A

biphosphonate therapy for osteoporosis: disfiguring jaw conditions involving serious infection and abnormal build-up of bone

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22
Q

what tissue is composed of 80% water, avascular, no nerve fibers, and flexible?

A

cartilage

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23
Q

what tissue do chondroblasts reside in?

A

cartilage

24
Q

what is the prominent proteoglycan in cartilage/bone?

A

chondroitin sulfate (electrostatic/proteoglycan repulsion)

25
Q

chondrocytes vs chondroblasts

A

chondrocytes are mature cells

chondroblasts are immature cells (undifferentiated)

26
Q

loss of what contributes to osteoarthritis and joint erosion?

A

loss of chondroitin sulfate

27
Q

what fibers are in hyaline cartilage?

A

Collagen II only
(weakest cartilage)

28
Q

what fibers are in fibrocartilage?

A

Collagen I & Collagen II
(strongest cartilage)

29
Q

what fibers are in elastic cartilage?

A

Elastin & Collagen II
(springy)

30
Q

does the perichondrium have a poor or rich blood supply?

A

rich blood supply
well innervated

31
Q

what are the layers of perichondrium?

A

Outer fibrous layer: resist expansion

inner chondrogenic layer: immature chondrogenic cells

32
Q

what is the most widespread cartilage?

A

hyaline

articular surfaces
costal cartilages
respiratory cartilages
nasal cartilages

33
Q

if hyaline cartilage is damaged, what often replaces it?

A

fibrocartilage

34
Q

composition of hyaline cartilage

A

spherical chondrocytes
collagen II only
perichondrium
no nerves/blood vessels

35
Q

what type of cartilage does not have a perichondrium?

A

fibrocartilage

*hyaline and elastic have perichondrium

36
Q

locations of elastic cartilage

A

external ear
nasal tip
eustachian tube
epiglottis

37
Q

fibrous covering in cartilage

A

perichondrium

38
Q

fibrous covering of bone

A

periosteum

39
Q

structural unit of bone

A

osteon

40
Q

Areas with higher % trabecular bone are found in the

A

vertebral column
proximal femur near pelvic girdle
distal radius

41
Q

what protein attaches osteoclasts to bone?

A

integrins

42
Q

what do osteoclasts dissolve?

A

hydroxyapatite (Ca2+ and Phos)
Collagen

43
Q

osteoclast vs osteoblast

A
44
Q

99% of calcium is stored in the ____

A

bones

45
Q

Parathyroid hormone (PTH) is secreted by _____ or the _______ glands

A

Parathyroid hormone (PTH) is secreted by CHIEF CELLS of the PARAthyroid glands

46
Q

calcitonin is secreted by what?

A

Calcitonin is secreted by the PARAFOLLICULAR CELLS of the thyroid gland

47
Q

what does calcitonin do?

A

inhibits the resorption of calcium from bone

inhibits osteoclast activity
less calcium in the blood

*oppositive of parathyroid hormone

48
Q

what two hormones regulate calcium levels in blood?

A

PTH (parathyroid hormone): increase Ca in blood
Calcitonin: decrease calcium in the blood

49
Q

What are the four ways in which calcitonin lowers Ca2+ levels in blood?

A
  1. inhibits Ca2+ absorption by intestines
  2. inhibits osteoclasts
  3. stimulates osteoblasts
  4. inhibits renal tubular cell reabsorption of Ca2+ (excreted in urine)
50
Q

glucocorticoids

A

hormone impacting Ca2+ metabolism
lowers calcium
inhibits osteoclasts

51
Q

growth hormone on Ca2+

A

increase calcium in blood

52
Q

estrogen on Ca2+

A

prevents osteoporosis

53
Q

insulin on Ca2+

A

increases bone formation

54
Q

rickets or osteomalacia

A

defective bone matrix calcification due to Vit D deficiency

55
Q

osteopetrosis

A

osteoblasts operate unopposed
fragile /distorted bone

56
Q

osteoporosis

A

excess osteoclast function

57
Q

disfiguring jaw condition involving serious infection and osteopetrosis

A

ONJ
Osteonecrosis of the Jaw (bisphosphonate-associated)