Chapter Eleven

Endocrine glands

Secrete hormones into interstitial fluid, then blood.

Exocrine glands

Secrete products via a duct.

Amines

Hormones derived from amino acid tyrosine.

Peptide hormones

Polypeptide chains, as short as 3 amino acids.

Steroid hormones

Lipid-soluble hormones with four carbon rings.

Epinephrine

Amine hormone secreted by adrenal medulla.

Norepinephrine

Amine hormone secreted by adrenal medulla.

Dopamine

Hormone secreted by the hypothalamus.

Prohormones

Inactive precursors of peptide and protein hormones.

Hormone transport

Peptide hormones are water-soluble; steroids are lipid-soluble.

Target cells

Cells with specific receptors for hormones.

Up-regulation

Increase in hormone receptors on target cells.

Down-regulation

Decrease in hormone receptors on target cells.

Tropic hormone

Hormone that regulates secretion of another hormone.

Hyposecretion

Secretion of too little hormone.

Hypersecretion

Secretion of too much hormone.

Hyporesponsiveness

Target cells fail to respond properly to hormones.

Hyperresponsiveness

Target cells respond excessively to hormones.

Adrenal cortex

Produces steroid hormones like cortisol and aldosterone.

Oxytocin

Stimulates milk ejection and uterine contractions.

Antidiuretic Hormone

Regulates water balance in the body.

Thyroid hormones

Regulate metabolism and growth development.

Cortisol

Stress hormone that regulates metabolism and inflammation.

Calcium homeostasis

Regulated by hormones affecting bone, kidneys, intestines.

Parathyroid hormone

Increases calcium reabsorption via osteoclasts.

Calcitonin

Inhibits osteoclast activity, lowering blood calcium.