Musculoskeletal

Question 1

Understand the funtion of bone cells: osteocytes, osteoclasts and osteoblasts and bone matrix constituants including proteoglycans, albumin, calcium and phosphate

Answer 1

Osteocytes

osteoclasts

osteoblasts

bone matrix

proteoglycans

glycoproteins

Albumin

Question 2

Osteocytes

Answer 2

are transformed osteoblast

signal formation

bone formation and reabsorption

maintains bone matrix

Question 3

Where are Osteocytes?

Answer 3

Within a space in the hardened bone matrix called the lacuna

Question 4

osteoclasts

break down bone

Answer 4

bone reabsorption cells (reuse)

meds used to treat osteoporosis inhibit osteocatic activity

RANKL drives osteoclasts being active

Question 5

Osteoblasts

build more bone

Answer 5

cells are derived from mesynchymal stem cells

• outer layer (work on the periosteom), produce and become osteoid (demileralized bone)
• production of collagenous amd non collagenous proteins that compose osteiod
• Active osteoblasts are lined up on the osteoid

Active osteoblasts are lined up on the osteoid

produceasteocalcin, TGF-B, macrophagecolony stimlating factor, receptor activator for nuclear factor ligand (TANKL), osteoprotegrin (OPG) and bone matrix and osteocalcin when stimulated by 1,25-dihydroxy-Vitamin D

initiate new formation of new bone by their synthesis of osteoid

Question 6

Bone Matrix

Answer 6

35% organic (produced by organism and has potential to degrade: collagen) and 65% inorganic (pre-exsist, don’t break down, not produced organism: K, Ca, Mg)

• collagen fibers
• calcium and phosphate minerals

*calcification begins as extracellular calcium enters the matrix vescicles and forms hydroxyapatite crystals

osteocalcin is a calcium-binding protein that binds preferentially to calcium that hasalready crystlized; it may also inhibit calcium ohosphate precipitation and to play a part of bone resportion by recruiting osteoclasts

Question 7

proteoglycans

Answer 7

-Primary Glucosamine and Chondroitin.

large complexes of numerous polysaccharides attatched to a common core

• Control transport and distribution of electrically charged particles (ions), particularly calcium, through the bone matrix, thereby playing a role in bone calcium deposition and calcification
• Glycosaminoglycans: chondrin sulfate and keritin sulfate
• strengthen bone by forming compression-resistant networks between the collagen fibrils

Question 8

Glycoprotein vs proteoglycan: Glycoprotein:

complete saccharides, more sinple and a protein complex

Answer 8

Ptoteoglycan:

mucopollysaccharides, multiple sugars but no other components