The mRNA for the transcription factor VegT, which becomes apportioned to the vegetal cells during cleavage. VegT is critical in generating both the endodermal and mesodermal lineages.

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.