Chapter 21
The Endocrine System
![An Overview of the Endocrine System](https://jovecdn2.ccindex.cn/files/media/science-education/science-education-thumbs/14972.jpg)
The endocrine system, a complex network of glands, orchestrates physiological balance within the body through the production and secretion of…
![Structures of the Endocrine System](https://jovecdn2.ccindex.cn/files/media/science-education/science-education-thumbs/14973.jpg)
The intricate framework of the endocrine system encompasses a diverse array of glands, with their target tissues and organs strategically distributed…
![Types of Hormones](https://jovecdn2.ccindex.cn/files/media/science-education/science-education-thumbs/14975.jpg)
Hormones are classified into four main groups: steroids, eicosanoids, amino acid-based derivatives, and peptide hormones.
Steroids and eicosanoids…
![Secondary Messengers in Hormone Action](https://jovecdn2.ccindex.cn/files/media/science-education/science-education-thumbs/14976.jpg)
Water-soluble hormones cannot cross the plasma membrane, so they rely on protein receptors that span the membrane to trigger intracellular signaling…
![Regulation of Hormone Secretion](https://jovecdn2.ccindex.cn/files/media/science-education/science-education-thumbs/14978.jpg)
Regulation of hormone secretion is a finely tuned orchestration driven by various types of stimuli, encompassing neural, humoral, and hormonal…
![The Pituitary Gland](https://jovecdn2.ccindex.cn/files/media/science-education/science-education-thumbs/14979.jpg)
The pituitary is a small endocrine organ in the sphenoid bone under the hypothalamus. Primarily, the pituitary in adults has two distinct anatomical…
![The Thyroid Gland](https://jovecdn2.ccindex.cn/files/media/science-education/science-education-thumbs/14981.jpg)
The thyroid gland is a small, butterfly-shaped gland located in the neck and covers the anterior surface of the trachea. The gland has two lateral…
![Synthesis and Regulation of Thyroid Hormones](https://jovecdn2.ccindex.cn/files/media/science-education/science-education-thumbs/14982.jpg)
Low blood levels of the thyroid hormones — triiodothyronine (T3) and thyroxine (T4) — signal the hypothalamus to release the…
![Synthesis and Functions of Calcitonin](https://jovecdn2.ccindex.cn/files/media/science-education/science-education-thumbs/14984.jpg)
Calcitonin, a vital polypeptide hormone, regulates calcium levels within body fluids. It is released by the parafollicular cells, also known as C…
![The Parathyroid Glands](https://jovecdn2.ccindex.cn/files/media/science-education/science-education-thumbs/14985.jpg)
The two pairs of parathyroid glands embedded within the posterior surface of the thyroid gland are restricted by a dense capsule around them. These…
![Hormones of the Adrenal Glands](https://jovecdn2.ccindex.cn/files/media/science-education/science-education-thumbs/14987.jpg)
Adrenal hormones play a pivotal role in maintaining the body's electrolyte balance and orchestrating responses to stress, showcasing the…
![Adrenal Gland Disorders](https://jovecdn2.ccindex.cn/files/media/science-education/science-education-thumbs/14988.jpg)
Adrenal gland disorders manifest when the production of adrenal hormones deviates from the norm, resulting in either excessive or insufficient…
![Gonadal and Placental Hormones](https://jovecdn2.ccindex.cn/files/media/science-education/science-education-thumbs/14990.jpg)
The gonads, namely the testes in males and the ovaries in females, are pivotal in producing gonadal hormones that orchestrate the intricate processes…
![Cells and Secretions of the Pancreas](https://jovecdn2.ccindex.cn/files/media/science-education/science-education-thumbs/14991.jpg)
The pancreas, a vital organ within the abdominal cavity, plays dual roles in the digestive and endocrine systems, collaborating with exocrine and…
![Multiplexed Fluorescent Immunohistochemical Staining of Four Endometrial Immune Cell Types in Recurrent Miscarriage](https://jovecdn2.ccindex.cn/files/thumbs/62931_t.png)
Immunohistochemistry is the most commonly used method for the identification and visualization of tissue antigens in biological research and clinical…
![An <em>Ex vivo</em> Culture System to Study Thyroid Development](https://jovecdn2.ccindex.cn/files/thumbs/51641_t.png)
The thyroid is a bilobated endocrine gland localized at the base of the neck, producing the thyroid hormones T3, T4, and calcitonin. T3 and T4 are…