Ch. 9 The Endocrine System

Marieb - Essentials of Human Anatomy & Physiology 13th Edition

Marieb13th EditionEssentials of Human Anatomy & PhysiologyISBN: 9780135624340Not the one you use?Change textbook

Marieb 13th Edition

Ch. 9 The Endocrine System

Problem 17

Chapter 9, Problem 17

Name three hormone antagonists of insulin and one of PTH.

Verified step by step guidance

Step 1: Understand the role of insulin. Insulin is a hormone secreted by the pancreas that lowers blood glucose levels by promoting glucose uptake into cells and stimulating glycogen synthesis.

Step 2: Identify hormones that counteract insulin's effects. These hormones are called insulin antagonists because they increase blood glucose levels by opposing insulin's actions.

Step 3: Learn about three key insulin antagonists: (1) Glucagon, which is secreted by the pancreas and raises blood glucose by stimulating glycogen breakdown in the liver, (2) Epinephrine (adrenaline), which is secreted by the adrenal medulla and increases blood glucose during stress by promoting glycogenolysis and gluconeogenesis, and (3) Cortisol, a glucocorticoid secreted by the adrenal cortex that raises blood glucose by stimulating gluconeogenesis and reducing glucose uptake by cells.

Step 4: Understand the role of parathyroid hormone (PTH). PTH is secreted by the parathyroid glands and increases blood calcium levels by stimulating bone resorption, increasing calcium reabsorption in the kidneys, and promoting activation of vitamin D.

Step 5: Identify one antagonist of PTH. Calcitonin, a hormone secreted by the thyroid gland, opposes PTH by lowering blood calcium levels through inhibition of bone resorption and increasing calcium deposition in bones.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Insulin Antagonists

Insulin antagonists are hormones that counteract the effects of insulin, which is responsible for lowering blood glucose levels. Key examples include glucagon, epinephrine, and cortisol. These hormones increase blood glucose levels by promoting gluconeogenesis, glycogenolysis, and inhibiting glucose uptake in tissues, thus maintaining energy balance during stress or fasting.

Glucagon

Glucagon is a peptide hormone produced by the alpha cells of the pancreas. It plays a crucial role in glucose metabolism by stimulating the liver to convert glycogen into glucose and release it into the bloodstream. This action raises blood sugar levels, making glucagon a primary antagonist of insulin, especially during periods of low blood sugar.

Parathyroid Hormone (PTH) Antagonist

The primary antagonist of parathyroid hormone (PTH) is calcitonin, which is produced by the thyroid gland. Calcitonin lowers blood calcium levels by inhibiting osteoclast activity in bones and reducing renal tubular reabsorption of calcium. This antagonistic relationship helps maintain calcium homeostasis in the body, counteracting the effects of PTH, which raises blood calcium levels.

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Related Practice

Textbook Question

Name two endocrine-producing glands (or regions) that are important in the stress response, and explain why they are important.

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Textbook Question

The parents of 14-year-old Megan are concerned about her height because she is only 4 feet tall and they are both close to 6 feet tall. After tests by their doctor, certain hormones are prescribed for the girl. What is the probable diagnosis? What hormones are prescribed, and why might the girl expect to reach normal height?

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Textbook Question

Describe the body location of each of the following endocrine organs: anterior pituitary, pineal gland, thymus, pancreas, ovaries, testes. Then, for each organ, name its hormones and their effect(s) on body processes. Finally, for each hormone, list the important results of its hypersecretion or hyposecretion.

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Textbook Question

Two hormones are closely involved in the regulation of the fluid and electrolyte balance of the body. Name them, and explain their effects on their common target organ.

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Textbook Question

The anterior pituitary is often referred to as the master endocrine gland, but it too has a 'master.' What controls the release of hormones by the anterior pituitary?

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Textbook Question

Mr. Flores brings his wife to the clinic, concerned about her nervousness, heart palpitations, and excessive sweating. Tests show hyperglycemia and hypertension. What hormones are probably being hypersecreted? What is the cause? What physical factors allow you to rule out thyroid problems?

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