Hormones & The Endocrine Glands 10.1 & 10.2

Image from: http://leavingbio

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 (Image from: http://schoolworkhelper.net/2010/07/the-endocrine-system-function-and-structure/

Animation… Narrated animation of water-soluble (protein) hormones. Specific example of using cAMP to activate proteins in the target cell: http://highered.mcgraw-hill.com/sites/0072943696/student_view0/chapter10/animation__second_messenger__camp.html

Fat-Soluble Hormones (Image from: http://nekaeportfolio.blogspot.com/2011/02/identifying-classes-of-hormones.html)

Animation… Narrated animation of steroid hormone action: http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/120109/bio46.swf::Mechanism%20of%20Steroid%20Hormone%20Action

Image from: http://bio1152. nicerweb. com/Locked/media/ch45/endocrine

Image from: http://www.mayoclinic.com/health/medical/IM00643

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 (Image from: http://www.ualberta.ca/~somji/pituitary.html)

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 ADH reabsorption of water in distal convoluted tubule Inhibited by alcohol & caffeine Oxytocin: childbirth, milk release

Image from: http://www. thyroiduk. org

Thyroid Glands stimulated by TSH secrete thyroxin (T4) in target cell, T4 is converted to T3, 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 Ca2+ levels in blood by stimulating deposition in bones, and reducing Ca2+ uptake by kidneys

Negative Feedback hypothalamus release TRH TRH causes the anterior pituitary to release TSH TSH causes the thyroid to release T4 T4 inhibits secretion of TSH by the anterior pituitary

Image from: http://www.mayoclinic.com/health/medical/IM03488

Parathyroid Glands produce parathyroid hormone (PTH) when Ca2+ levels are too low, PTH is released: stimulates bones to release Ca2+ stimulates kidneys to activate vitamin D, which acts on cells in intestines to increase Ca2+ absorption

Image from: http://www. nichd. nih

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

Image from: http://healinghaven. typepad

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