9.1 - Endocrine System

Endocrine System

A system that uses chemical messages (hormones) released into the bloodstream, having slower and longer-lasting effects than the nervous system.

Function of the Endocrine System

Includes reproduction, growth and development, mobilization of body defenses, maintenance of homeostasis, regulation of metabolism, blood sugar, and water balance.

Endocrinology

The medical specialty that studies disorders of the endocrine system.

Hormone

A chemical messenger sent to many parts of the body to produce a specific effect on a target cell or organ.

Exocrine Glands

Glands that transport substances to target tissues via ducts to the surface of the body or body cavities, such as tear and salivary glands.

Endocrine Glands

Ductless glands that secrete hormones directly into the bloodstream.

Steroid Hormones

Lipid-based hormones that can easily diffuse through cell membranes and bind to internal receptors; examples include testosterone and estrogen.

Water-Soluble Hormones

Hormones, such as amino-acid based hormones, that bind to receptor proteins on the cell surface, initiating a cascade of reactions.

Tropic Hormones

Hormones that target other endocrine glands and stimulate them to release additional hormones.

Hormonal Stimuli

A type of stimulus that activates endocrine glands through the presence of hormones.

Neural Stimuli

Hormone release triggered by nerve impulses, often under control of the sympathetic nervous system.

Feedback Inhibition

A regulatory mechanism where the output of a process inhibits its own production to maintain homeostasis.

Pineal Gland

A major endocrine organ involved in regulating sleep patterns and circadian rhythms.

Hypothalamus

A brain region that plays a crucial role in hormone regulation and maintaining homeostasis.

Pituitary Gland

Often referred to as the 'master gland' because it regulates other endocrine glands and their hormone release.

Thyroid Gland

An endocrine gland that influences metabolism and growth through the release of thyroid hormones.

Parathyroid Gland

Glands located on the dorsal aspect of the thyroid that regulate calcium levels in the blood.

Adrenal Glands

Glands that produce hormones related to stress responses and metabolism.

Insulin

A hormone produced by the pancreas that regulates blood sugar levels.

Epinephrine

A water-soluble hormone that triggers the breakdown of glycogen into glucose during stress responses.

Cyclic AMP (cAMP)

A second messenger involved in the action of water-soluble hormones.