When the L-type calcium channels become inactivated at about the same time, greatly increased numbers of potassium channels open.

TLS Online TPP Program

#Id: 1231

#Unit 7. System Physiology – Animal

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

TLS Online TPP Program

#Id: 1232

#Unit 7. System Physiology – Animal

In the intestine,

1,25-dihydroxycholecalciferol induces the synthesis of calbindin D-28 K which promotes Ca2+ absorption.

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#Id: 1233

#Unit 7. System Physiology – Animal

1,25-dihydroxycholecalciferol stimulates the reabsorption of calcium & phophate ions from kidney.

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#Id: 1234

#Unit 7. System Physiology – Animal

In bone, 

1,25-dihydroxycholecalciferol acts synergistically with PTH to stimulate osteoclast activity and bone resorption.

TLS Online TPP Program

#Id: 1235

#Unit 7. System Physiology – Animal

The anterior pituitary secretes six peptide hormones: TSH, FSH, LH, GH, prolactin, & ACTH

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#Id: 1236

#Unit 7. System Physiology – Animal

Thyrotropin-releasing hormone (TRH) Tripeptide stimulates secretion of TSH by thyrotropes