Physio of Bone Flashcards

0
Q
Abreeivations 2
PGE2
Pi
PPi
PTH
RANKL
TNAP
TNF
A
Prostagladin E2
inorganic phosphate
pryophosphate
parathyroid hormone
RANK ligand
tissue-nonspecific alkanine phospohoptae
Tumor nerotic factor
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1
Q
Abreviations 1
ANKH
CT
I-1
M-CSF
NPP1
OPG
A

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

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2
Q

Bone Functions

A

Structure Integrity
Movement of Limbs
Storage of Calcium and Phosphate
Hematopoeisis

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3
Q

Processes within Bone

A

Growth
Modeling
Remodeling
Repair

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4
Q

Bone - components

A
Collagen fibers (Type I)
Calcium phosphate salts
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5
Q

_________ are responsible for building and maintaining bone tissue

A

cells

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6
Q

Bone modeling - define

A

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

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7
Q

Bone remodeling - define

A

repair of microdaamage that occurs

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8
Q

Blood flow in resting skeletal muscle v blood flow to bone

A

4 v 10 ml per 100/mn

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9
Q

Cells that make up bone

A

Osteoblasts
Osteocytes
Osteoclasts
Lining cells periosteal and endosteal

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10
Q

Osteoblasts - origin, location, function (details)

A

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

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11
Q

Osteocytes - origin, location, function (explain)

A

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)

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12
Q

Lining cells - origin, location, function

A

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

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13
Q

Osteoclasts - origin, location, function

A

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

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14
Q

Osteoblasts and osteoclasts activity are stimulated by ….

A

Cytokines
Other chemical messengers
Vit D
Parathyroid hormone (PTH)

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15
Q

PTH def & activity

A

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
Q

Vit D

A

Acts to increase intestinal absorption of Ca2+

17
Q

Osteoblast to osteocclast process simplified

A

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
Q

Osteopontin

A

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

19
Q

Bone Sialo protein

A

BSP
part of collagen - aids crystallization of hydroapatite
Osteoblasts

20
Q

TNAP

A

Promotes precipitation by hydrolizing PPi into Pi.

Promotes Osteoblast activity (increase Mineralization)

21
Q

NNP1

A

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

22
Q

hypophospatasia

A

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
Q

epiphyses - def

A

ends of bones

24
Q

epiphyseal plate - def.

A

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

25
Q

Bone remodeling - fxns, method

A

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
Q

PTH - OB/OC effects

A

Inc OB
Inc OC
Paradox

27
Q

Vit D

A

Inc OB
Inc OC
Paradox

28
Q

Calcitonin (CT) - OB/OC effects

A

Dec OC

29
Q

Estrogen - OB/OC effects

A

Dec OB

Dec OC

30
Q

Testosterone - OB/OC effects

A

Dec OB

Dec OC

31
Q

IGF - OB/OC effects

A

Inc OB

Inc OC

32
Q

Thyroid Hormone - OB/OC effects

A

Inc OB

Inc OC

33
Q

Cortisol - OB/OC effects

A

Inc OB

Dec OC

34
Q

Bone repair process

A

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

35
Q

ANK

A

Decrease bone mineralization by increasing PPi

36
Q

BSP

A

?