The Endocrine System and Hormonal Regulation

1. The endocrine system is a network of glands and organs that produce and release hormones.
2. Hormones travel to target cells or organs, where they bind to specific receptors and trigger a response.
3. The endocrine system works in conjunction with the nervous system to maintain homeostasis, control metabolism, growth, development, and reproduction, and respond to stress.
4. Hormone secretion is typically regulated by feedback mechanisms, ensuring that hormone levels are kept within a certain range.

Major Endocrine Glands and Their Functions

1. The main glands involved in the endocrine system are responsible for producing and secreting hormones into the bloodstream.
2. These hormones are then transported to target organs or cells where they exert their effects.

Types of Hormones

Non-Steroid Hormones

1. Water-soluble and cannot cross cell membranes.
2. Bind to receptors on the surface of target cells, triggering a cascade of intracellular signaling.

Steroid Hormones

1. Fat-soluble and can pass through cell membranes.
2. Bind to intracellular receptors and directly influence gene expression.

Examples of Hormones and Their Functions

Hormones regulate a wide variety of biological processes. Below are some key examples and their functions:

Pituitary Gland - The “Master Gland”

1. The pituitary gland is often called the “master gland” because it controls many of the body's endocrine functions by regulating other glands.
2. Despite its small size (just about the size of a pea), it plays a central role in growth, metabolism, stress response, and reproduction.

Hormones of the Pituitary Gland

Anterior Pituitary Hormones

Posterior Pituitary Hormones

Endocrine Hormones and Their Impact on Physiological Functions