Functional Organization of the Endocrine System

Flashcards for key concepts and terminology related to the functional organization of the endocrine system.

Endocrine Glands

Glands that secrete hormones directly into the bloodstream.

Hormone

Chemical messengers secreted by endocrine glands that regulate physiological processes.

Target Tissue

Specific tissue that responds to a particular hormone.

Endocrine System

Major control system regulating various physiological processes via hormones.

Exocrine Glands

Glands that secrete substances through ducts to the outside of the body or into the digestive system.

Homeostasis

The process of maintaining a stable internal environment in the body.

Hormonal stimuli

Hormones that stimulate the secretion of other hormones.

Humoral stimuli

Direct response from the bloodstream that stimulates hormone release.

Neural stimuli

Hormones released in response to neurotransmitter signals.

Receptor

Protein on a target cell that binds a hormone and initiates a response.

Agonist

A drug that binds to a receptor and activates it.

Antagonist

A drug that binds to a receptor but inhibits its action.

Feedback Mechanisms

Processes that regulate hormone levels; includes negative and positive feedback.

Down-regulation

Decrease in the number of receptors, leading to reduced hormone sensitivity.

Up-regulation

Increase in the number of receptors, enhancing hormone sensitivity.

Second Messengers

Molecules that relay signals received at receptors on the cell surface, to target molecules inside the cell.

Nuclear Receptors

Receptors for lipid-soluble hormones that regulate gene expression.

Membrane-bound Receptors

Receptors for water-soluble hormones that initiate responses inside the cell.