Human Anatomy and Physiology : Help with Thyroid and Parathyroid Physiology

Study concepts, example questions & explanations for Human Anatomy and Physiology

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Example Questions

Example Question #41 : Systems Physiology

Which of the following glands would be most active in a person with low blood calcium levels?

Possible Answers:

Thyroid gland

Pancreas

Pituitary gland

Thymus gland

Parathyroid gland

Correct answer:

Parathyroid gland

Explanation:

In accordance with negative feedback and homeostasis, low blood calcium levels will cause the body to release a hormone in order to raise calcium levels. Parathyroid hormone is a hormone that acts to raise blood calcium levels by stimulating osteoclast activity, releasing stored calcium from bone into the blood. The parathyroid gland would be most active during low blood calcium in order to initiate this effect.

The thyroid gland is involved in raising blood calcium levels (calcitonin) and mediating metabolism (T3 and T4). The pancreas moderates blood glucose levels (insulin and glucagon). The pituitary gland is associated with several processes, including stimulation of other endocrine glands, but is not linked to parathyroid activity. The thymus is located superior to the heart and is the location of maturation for T-lymphocytes; it also secretes certain hormones that affect immune system maintenance and development.

Example Question #42 : Systems Physiology

Which hormone increases blood calcium levels? 

Possible Answers:

Thyroid-stimulating hormone

Aldosterone 

Parathyroid hormone

Calcitonin

Correct answer:

Parathyroid hormone

Explanation:

When blood calcium levels are low, parathyroid hormone is released to increase calcium reabsorption of the kidneys and to stimulate osteoclasts, which are responsible for bone resorption. These processes serve to increase blood calcium levels.

Parathyroid hormone is an antagonist to calcitonin, which is released from the thryoid gland and increases blood calcium levels.

Example Question #41 : Endocrine Physiology

What is the function of calcitonin?

Possible Answers:

Increases calcium levels

Increases heart rate

Binds T4 to T3

Decreased calcium levels

Correct answer:

Decreased calcium levels

Explanation:

Calcitonin is produced by the C-cells located in the thyroid gland and its main function is to decrease plasma calcium. This is done primarily through the activation of osteoblasts, which take calcium in the blood and store it in bone.

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