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Flashcards in Physio of Bone Deck (37):
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Abreviations 1
ANKH
CT
I-1
M-CSF
NPP1
OPG

Adensosine triphosphate
Calcitonin
Interlukin-1
macrophage-colony stimulating factor
ectonuceotide pyrophostphataese/phosphodiesterase
Osteoprotegerin (ostoclastic inhibiting factor)

1

Abreeivations 2
PGE2
Pi
PPi
PTH
RANKL
TNAP
TNF

Prostagladin E2
inorganic phosphate
pryophosphate
parathyroid hormone
RANK ligand
tissue-nonspecific alkanine phospohoptae
Tumor nerotic factor

2

Bone Functions

Structure Integrity
Movement of Limbs
Storage of Calcium and Phosphate
Hematopoeisis

3

Processes within Bone

Growth
Modeling
Remodeling
Repair

4

Bone - components

Collagen fibers (Type I)
Calcium phosphate salts

5

_________ are responsible for building and maintaining bone tissue

cells

6

Bone modeling - define

altering the structure of a bone in response to the mechanical laods placed on it

7

Bone remodeling - define

repair of microdaamage that occurs

8

Blood flow in resting skeletal muscle v blood flow to bone

4 v 10 ml per 100/mn

9

Cells that make up bone

Osteoblasts
Osteocytes
Osteoclasts
Lining cells periosteal and endosteal

10

Osteoblasts - origin, location, function (details)

Mesenchyma Stem cells
Surface of the bone
Formation of bone - Lay down collagen fibers, deposit Ca2+ & PO43- in matrix

11

Osteocytes - origin, location, function (explain)

Osteoblasts
In bone channels or canaliculi
I) Sensing mechanical strain; II) Transport of Calcium and phosphate
I) (strain causes bone fluid movement in canaliculi. movement transduced into electrical signal. signal tells through osteocytes activates osteoblasts)
II) (osteocytes express PTH receptors. When Ca2+ decreases/PTH increases, osteocytic osteolysis begins. Osteocytes release Ca2+ into plasma compartment to maintain Ca2+ homeostasis. NOT bone resorption)

12

Lining cells - origin, location, function

Osteoblasts
Periosteal and endosteal surfaces of the bone
I) Regulate movement of calcium and phosphate into and out of the bone
II) can become an osteoblast again, if needed

13

Osteoclasts - origin, location, function

Hematopoietic stem cells
Surface of the bone
Breakdown/Resorption of bone - destroy matrix, fee Ca2+/PO43-

14

Osteoblasts and osteoclasts activity are stimulated by ....

Cytokines
Other chemical messengers
Vit D
Parathyroid hormone (PTH)

15

PTH def & activity

Primary endocrine regulator of bone remodeling. Secreted in response to decreased plasma Ca2+. Stimulates Osteoblastic activity and stimulates osteoclast activity INDIRECTLY. needs normal levels of VitD to have effect

16

Vit D

Acts to increase intestinal absorption of Ca2+

17

Osteoblast to osteocclast process simplified

Osteoblast release M-CSF. M-CSF induces osteoclasts precursors. M-CSF acts with RANKL. RANK (receptor on osteoclast precursor membrane) induces osteoclastogenesis. Osteoclasts dissolve calcified crystals and release Ca2+ and Pi ino blood.

18

Osteopontin

OPN
Acidic protein. when phosphorylated, generates strong negative charge
Binds strongly to Ca2+, inhibiting mineralization
Expression increased with hypocalcemia and hypophospatemia
Osteoclast

19

Bone Sialo protein

BSP
part of collagen - aids crystallization of hydroapatite
Osteoblasts

20

TNAP

Promotes precipitation by hydrolizing PPi into Pi.
Promotes Osteoblast activity (increase Mineralization)

21

NNP1

Uses ATP and ADP to form PPi , which inhibits matrix mineralization

22

hypophospatasia

An inborn error of metabolism caused by a deficiency in the TNAP isoenzyme
Diagnosed by a low serum TNAP level and accumulation of phosphocompunds (e.g. PPi)

23

epiphyses - def

ends of bones

24

epiphyseal plate - def.

layer of cartilage separating the head of the bone from the shaft

25

Bone remodeling - fxns, method

Contributes to Ca2+ regulation by moving calcium into or out of bone
Repairs micro-damage
Old bone reabsorbed (osteoclasts) then new bone deposited (osteoblasts) - Occurs @ surface

26

PTH - OB/OC effects

Inc OB
Inc OC
Paradox

27

Vit D

Inc OB
Inc OC
Paradox

28

Calcitonin (CT) - OB/OC effects

Dec OC

29

Estrogen - OB/OC effects

Dec OB
Dec OC

30

Testosterone - OB/OC effects

Dec OB
Dec OC

31

IGF - OB/OC effects

Inc OB
Inc OC

32

Thyroid Hormone - OB/OC effects

Inc OB
Inc OC

33

Cortisol - OB/OC effects

Inc OB
Dec OC

34

Bone repair process

Hematoma -> Soft callus -> Hard callus -> Bone

35

ANK

Decrease bone mineralization by increasing PPi

36

BSP

?