Copy of Lab 8 Mini Lesson Learning Guides

Autocrine signaling

A cell releases a chemical messenger that acts on the same cell that secreted it.

Paracrine signaling

A cell releases a chemical messenger that acts on nearby cells.

Neurotransmitter signaling

A neuron releases a neurotransmitter that binds to receptors on another neuron or effector cell.

Endocrine signaling

Endocrine glands secrete hormones into the bloodstream to act on distant target cells.

Exocrine signaling

Glands secrete substances into ducts that lead outside the body or into internal cavities.

Neurocrine signaling

A neuron releases a chemical messenger that enters the bloodstream (neurohormones).

Hormone

A chemical messenger secreted by endocrine glands that travels in the bloodstream to regulate distant target cells.

Neurohormone

A hormone secreted by neurons (e.g., oxytocin, vasopressin).

Protein/Peptide Hormones

Hormones made of chains of amino acids, water-soluble, and have rapid effects.

Steroid Hormones

Hormones derived from cholesterol, lipid-soluble, and synthesized on demand.

Amine Hormones

Hormones derived from tyrosine or tryptophan, including catecholamines and thyroid hormones.

Catecholamines

A class of amine hormones (epinephrine, norepinephrine, dopamine) produced by the adrenal medulla.

Tropic hormones

Hormones that regulate the secretion of another hormone.

Trophic hormones

Hormones that promote the growth and maintenance of target tissues.

Hyposecretion

Insufficient hormone production by a gland.

Hypersecretion

Excess hormone production by a gland.

Hypothalamus

Region of the brain that integrates signals and regulates endocrine function.

Anterior Pituitary

Part of the pituitary gland regulated by hypothalamic hormones via portal vessels.

Posterior Pituitary

Part of the pituitary gland connected by axons, releasing neurohormones from the hypothalamus.

Oxytocin

A peptide hormone that stimulates uterine contractions and milk ejection.

Vasopressin (ADH)

A peptide hormone that regulates water balance.

Negative feedback loop

A mechanism that maintains homeostasis by inhibiting further hormone secretion in response to a hormone's effects.

Amplification

The process by which one hormone molecule can activate many intracellular molecules.