Imbalance

Thyroid Factor

The Natural Thyroid Diet

Get Instant Access

Ca2+ concentration greater or less than 11 mg/ml blood

High Low

Thyroid gland (front view)

Blood Ca2+high: thyroid secretes calcitonin

Thyroid gland (front view)

High Low

Trachea

Blood Ca2+ low: parathyroids secrete parathormone

Parathyroid gland (rear view)

Blood Ca2+ low: parathyroids secrete parathormone

Parathyroid gland (rear view)

Calcitonin stimulates osteoblasts to take up Ca2+ from blood and lay down new bone.

Parathormone stimulates osteoclasts to resorb bone and return Ca2+ to blood; it also stimulates the absorption of calcium from the intestines and decreased loss of calcium from the kidneys.

Bone Blood vessel

Osteoclasts

Bone Blood vessel

Osteoclast Calcitonin

Osteoclasts

42.9 Hormonal Regulation of Calcium Calcitonin, parathyroid hormone,and vitamin D help regulate blood calcium levels.

42.9 Hormonal Regulation of Calcium Calcitonin, parathyroid hormone,and vitamin D help regulate blood calcium levels.

citonin decreases the activity of osteoclasts and thereby shifts the balance of bone turnover to favor deposition of bone and removal of calcium from the blood. Because the turnover of bone in adult humans is not very high, calcitonin does not play a major role in calcium homeostasis in adult humans. It is probably more important in young, growing individuals, but overall, calcium levels are more influenced by parathyroid hormone than by calcitonin.

Was this article helpful?

0 0
Essentials of Human Physiology

Essentials of Human Physiology

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.

Get My Free Ebook


Responses

  • brendan
    How does the body regulate blood calcium levels?
    8 years ago

Post a comment