Question

Growth hormone is produced by the a. posterior adrenal gland. b. posterior pituitary. c. anterior pituitary. d kidneys. e. None of these is correct.

Short answer

Growth hormone is produced by the \(c. anterior pituitary\).

Step-by-step solution

Define the growth hormone

The growth hormone, also known as somatotropin, is a peptide hormone that stimulates growth, cell reproduction, and cell regeneration in humans and other animals.

Eliminate irrelevant options

In this step, we will eliminate options that are not associated with hormone production or are not recognized as potential sources for growth hormone production. a. Posterior adrenal gland: The adrenal glands are responsible for the production of certain steroid hormones, such as cortisol and aldosterone. However, they are not responsible for the production of growth hormone. Therefore, we can eliminate this option. d. Kidneys: The primary function of the kidneys is the filtration of blood and removal of waste products from the body. While they do play a role in hormone production, specifically erythropoietin, they do not produce the growth hormone. Thus, we can eliminate this option as well.

Determine the correct source of growth hormone production

After eliminating the irrelevant options, we are left with three potential sources: posterior pituitary, anterior pituitary, and none of these. b. Posterior pituitary: The posterior pituitary releases hormones, such as antidiuretic hormone (ADH) and oxytocin, which are produced in the hypothalamus. However, it does not produce growth hormone. c. Anterior pituitary: The anterior pituitary is responsible for the production of several hormones, including growth hormone. This is the correct answer. e. None of these is correct: Since we have now identified the anterior pituitary as the source of growth hormone production, this option can be dismissed.

Conclusion

Growth hormone is produced by the c. anterior pituitary.

Key concepts

Anterior Pituitary

The anterior pituitary, also known as adenohypophysis, plays a pivotal role in the regulation of several key functions in the human body through the secretion of hormones. One of its most significant functions is the production of growth hormone (GH), also known as somatotropin. This particular hormone is crucial for a variety of biological processes, including growth in children and adolescents, and the regulation of metabolism in adults.

Location and Structure

Located at the base of the brain, the anterior pituitary is a glandular portion of the pituitary gland. It's connected to the hypothalamus by blood vessels, a setup that allows it to receive signals from this vital brain region. The hypothalamus sends releasing hormones to the anterior pituitary, stimulating or suppressing the release of specific hormones.

Hormones Produced by Anterior Pituitary

Other than GH, the anterior pituitary secretes multiple hormones that influence growth, sexual development, skin pigmentation, and thyroid function. It includes hormones like prolactin, which promotes lactation; follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which regulate reproductive processes; adrenocorticotropic hormone (ACTH), which stimulates the adrenal glands; and thyroid-stimulating hormone (TSH), which induces the thyroid gland to produce thyroid hormones.

Human Endocrine System

The human endocrine system consists of a network of glands that release hormones to regulate various body functions. This intricate system ensures a steady internal environment known as homeostasis by affecting growth, metabolism, and reproduction among other physiological aspects.

Components and Functions

The endocrine system includes the anterior pituitary gland, thyroid, parathyroid, adrenal glands, pancreas, ovaries in females, and testes in males. Each gland has a specific role, secreting hormones directly into the bloodstream to target distant organs and cells. These hormones serve as chemical messengers that cause changes within the body.

Coordination with the Nervous System

While the nervous system transmits information between specific locations quickly, the endocrine system provides a slower, but longer-lasting, method of control through hormones. Together, they coordinate to maintain various bodily functions and respond to both internal and external stimuli.

Feedback Mechanisms

Feedback mechanisms are vital for the function of the endocrine system. Negative feedback loops, in particular, regulate hormone levels. When a hormone is found in excess, the system responds by reducing its production—a principle vital in maintaining the balance within the system and the body as a whole.

Peptide Hormones

Peptide hormones are a class of hormones made up of chains of amino acids that are synthesized and secreted by various glands within the endocrine system. Unlike steroid hormones, which are fat-soluble, peptide hormones are water-soluble, allowing them to travel freely in the bloodstream without carriers.

Mode of Action

Upon reaching their target cells, peptide hormones bind to specific receptors on the cell surface, which triggers a series of reactions within the cell. These reactions result in the cellular changes required for the expression of the hormone's effects, such as activating or deactivating certain enzymes or genes.

Examples and Functions

Growth hormone, insulin, glucagon, and antidiuretic hormone (ADH) are all examples of peptide hormones. Growth hormone, for instance, promotes growth and repair throughout the body. Insulin and glucagon help manage blood glucose levels, and ADH regulates the body's water balance.

Synthesis and Storage

Peptide hormones are synthesized in the endoplasmic reticulum of cells and stored in vesicles until signals prompt their release. This allows the body to have a readily available supply of hormones that can be released quickly in response to various stimuli.