The rate of sedimentation is dependent upon the applied centrifugal field (cm s-2), G,

that is determined by the radial distance, r, of the particle from the axis of rotation (in cm)

and the square of the angular velocity ω, of the rotor (in radians per second):

TLS Online TPP Program

#Id: 1226

#Unit 7. System Physiology – Animal

Vitamin D and PTH appear to stimulate production of mature osteoclasts through the dual action:

 1. Inhibiting OPG production

2. Stimulating RANKL formation

TLS Online TPP Program

#Id: 1227

#Unit 7. System Physiology – Animal

Glucocorticoids promote osteoclast activity and bone resorption by :

1. Increasing RANKL production 

2. Decreasing formation of OPG

TLS Online TPP Program

#Id: 1228

#Unit 7. System Physiology – Animal

Estrogen stimulates OPG production

TLS Online TPP Program

#Id: 1229

#Unit 7. System Physiology – Animal

PTH actions on the kidney:

1.  Inhibits phosphate reabsorption

2.  Stimulates Ca2+ reabsorption

TLS Online TPP Program

#Id: 1230

#Unit 7. System Physiology – Animal

PTH stimulates renal 1α-hydroxylase.

TLS Online TPP Program

#Id: 1231

#Unit 7. System Physiology – Animal

1α-hydroxylase, converts 25-hydroxycholecalciferol to the active form, 1,25-dihydroxycholecalciferol.