Endocrine System Lecture Flashcards

Endocrine Gland

A ductless gland that synthesizes and secretes chemical messengers (hormones) directly into body fluids or the blood to regulate metabolic processes.

Paracrine Secretion

A mechanism of chemical signaling in which secretions affect nearby but different cell types after being released into the extracellular space.

Autocrine Secretion

A mechanism of chemical signaling in which secreted substances exert their effects on the same cell or cell type that secreted them into the interstitial fluid.

Steroid Hormones

Fat-soluble hormones derived from cholesterol that diffuse through the cell membrane, bind to intracellular receptors, and activate gene expression in the nucleus.

Nonsteroid Hormones

Hormones derived from amino acids that act as a first messenger by binding cell membrane receptors, activating adenylate cyclase, and generating cyclic AMP as a second messenger.