Chapter 30, Problem 1O

Summary Introduction

To describe:

The function of the anterior pituitary and posterior gland and their impact on the human body.

Introduction:

Endocrine glands are ductless, hence, they (for example, pituitary and thyroid glands) release their hormones or products into the bloodstream. Endocrine glands have intracellular effects and they are mainly involved in metabolisms. The hypothalamus and the pituitary gland are primarily involved in the endocrine hormone cascade pathway, and they stimulate signals to their target glands or organs. The hypothalamus is located in the brain, below the thalamus. It links the nervous and the endocrine system through the pituitary gland. It synthesizes releasing hormones and inhibitory hormones, which control the anterior pituitary and the posterior pituitary.

Explanation of Solution

The anterior pituitary:

The anterior lobe of the pituitary is derived from the invagination of the oral ectoderm. The hypothalamus communicates with the anterior pituitary through hormones. Based on nerve signals the hypothalamus secretes hormones, which stimulate or inhibit the production of hormones from the anterior pituitary. The hypothalamus hormones reach the anterior pituitary through the hypophyseal portal system (complex of blood vessels) and control the pituitary. The anterior pituitary synthesizes and secretes six endocrine hormones.

The posterior pituitary:

The posterior pituitary or posterior lobe is an extension of the hypothalamus nervous tissues and it is not a true gland. The hypothalamus regulates the posterior pituitary through neuroendocrine reflexes. The posterior pituitary hormones, namely antidiuretic hormone (ADH) and oxytocin (OT) are synthesized by neurosecretory cells located in the hypothalamus. Then these hormones travel and store in the posterior pituitary. The posterior pituitary hormones will be released when they receive the response or signals from the hypothalamus.

Conclusion

The hypothalamus controls the release of all hormones from the anterior pituitary. The anterior pituitary hormones regulate metabolism, growth, and reproduction and also regulate other endocrine glands and tissues. The hypothalamus controls the release of ADH and oxytocin from the posterior pituitary. The posterior pituitary hormones regulate water retention by the kidney and involved in the reproduction.