While raising blood calcium levels, PTH lowers blood phosphate levels by promoting urinary excretion of phosphate. Explain why this is important for achieving the purpose of PTH.
Saladin: Anatomy & 7. Bone Tissue Text © The McGraw-Hill
Physiology: The Unity of Companies, 2003 Form and Function, Third Edition
234 Part Two Support and Movement
^ W Blood calcium m T concentration
Correction for hypercalcemia
Less bone _ resorption
More bone deposition "
Reduced ■ osteoclast ■ activity
Increased osteoblast activity
^ A Blood calcium W concentration T
Correction for hypocalcemia
More bone resorption
Less bone deposition t
Prevention of " hydroxyapatite " formation
Conservation of calcium
Increased osteoclast activity
Reduced ■ osteoblast activity
More urinary phosphate excretion
_ Less urinary calcium excretion
Figure 7.16 Negative Feedback Loops in Calcium Homeostasis. (a) The correction of hypercalcemia by calcitonin. (b) The correction of hypocalcemia by parathyroid hormone.
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This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.