Hormones & The Endocrine Glands 10.1 & 10.2

Hormones chemicals produced by cells in one part of the body that regulate processes in another part of the body endocrine glands secrete hormones directly into the blood (exocrine glands into ducts)

Endocrine vs. Nervous both systems integrate and control organs and tissues nervous system helps body to adjust quickly to changes endocrine system maintains control over longer periods of time

Types of hormones protein hormones are amino acid chains and are water-soluble; diffuse well through blood and fluids steroid hormones are derived from cholesterol and are soluble in blood when combined with hydrophilic carrier proteins

Water-Soluble Hormones

Animation… Narrated animation of water-soluble (protein) hormones. Specific example of using cAMP to activate proteins in the target cell: hill.com/sites/ /student_view0/chapter10/ animation__second_messenger__camp.htmlhttp://highered.mcgraw- hill.com/sites/ /student_view0/chapter10/ animation__second_messenger__camp.html

Fat-Soluble Hormones

Animation… Narrated animation of steroid hormone action: hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/si tes/dl/free/ /120109/bio46.swf::Mechanis m%20of%20Steroid%20Hormone%20Actionhttp://highered.mcgraw- hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/si tes/dl/free/ /120109/bio46.swf::Mechanis m%20of%20Steroid%20Hormone%20Action

Hypothalamus part of the nervous system produces neurohormones which diffuse into the blood and travel to the pituitary gland

Pituitary Gland “master gland” secretes hormones that control other endocrine glands under the nervous control of the hypothalamus

Pituitary Gland

Anterior Pituitary neurohormones from the hypothalamus stimulate or inhibit release of hormones produces, stores & releases: –prolactin (PSH) –growth hormone –tropic hormones (TSH, ACTH, FSH, LH) –melanocyte-stimulating hormone MSH

“Intermediate Lobe” not very developed in humans releases endorphins, “natural painkillers” endorphins function in the nervous system in pathways that control pain)

Posterior Pituitary stores and releases hormones produced by the hypothalamus: –anti-diuretic hormone (ADH) –oxytocin

Thyroid Glands stimulated by TSH secrete thyroxin (T 4 ) in target cell, T 4 is converted to T 3, triiodothyronine, which enters nucleus and combines with receptors affects growth, development, metabolism, etc.

Thyroid Glands also has specialized cells that secrete calcitonin (protein hormone) lowers Ca 2+ levels in blood by stimulating deposition in bones, and reducing Ca 2+ uptake by kidneys

Negative Feedback hypothalamus release TRH TRH causes the anterior pituitary to release TSH TSH causes the thyroid to release T 4 T 4 inhibits secretion of TSH by the anterior pituitary

Parathyroid Glands produce parathyroid hormone (PTH) when Ca 2+ levels are too low, PTH is released: –stimulates bones to release Ca 2+ –stimulates kidneys to activate vitamin D, which acts on cells in intestines to increase Ca 2+ absorption

Adrenal Glands adrenal medulla secretes epinephrine & norepinephrine –“fight or flight” situations adrenal cortex secretes hormones such as aldosterone (osmoregulation), cortisol (blood glucose regulation)

Pineal Gland regulates biological rhythms due to secretion of melatonin light (detected by the eye) inhibits melatonin secretion