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Endocrine System . The Importance of the Endocrine System. Introduction. The trillions of cells of the body all interact with each other—no cell operates in isolation.
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Endocrine System The Importance of the Endocrine System
Introduction • The trillions of cells of the body all interact with each other—no cell operates in isolation. • Hormones are chemical regulators produced by cells in one part of the body that affect cells in another part of the body http://www.pituitarysociety.org/public/overview/normalpituitary?printablepage=1
Endocrine hormones • Only small amounts of hormones are needed to affect the target organs • Endocrine hormones are chemicals produced in glands and secreted directly into the blood • The circulatory system carries these hormones to the various organs of the body.
Steroid and Protein Hormones • How do hormones signal cells? http://www.hcc.uce.ac.uk/physiology/endocrinesystem.htm
Steroid and Protein Hormones • Specific hormones do not affect all cells. • Cells may have receptors for one hormone but not another. • The number of receptors found on individual cells also may vary. • There are two types of hormones, which differ in chemical structure and action.
Steroid Hormones • Made from cholesterol (a lipid compound) • Includes male and female sex hormones and cortisol • Steroid molecules are composed of complex rings of carbon, hydrogen, and oxygen molecules and are not soluble in water but are soluble in fat. http://www.novatec-id.com/products/hormone-markers/steroid/
Steroid Hormones • Steroid hormones diffuse from the capillaries into the interstitial fluid and then into the target cells • they combine with receptor molecules located in the cytoplasm
Steroid Hormones • The hormone–receptor complex then moves into the nucleus and attaches to a specific site on the DNA • The hormone activates a gene • Ribosomes begin producing a specific protein http://163.16.28.248/bio/activelearner/47/ch47c1.html
Protein Hormones • Includes insulin and growth hormone • These hormones contain chains of amino acids of varying length and are soluble in water http://www.nibsc.ac.uk/science/diagnostics/protein_hormones__endocrine_p.aspx
Protein Hormones • Protein hormones combine with receptors on the cell membrane • Some of the protein hormones form a hormone– receptor complex that activates the production of an enzyme called adenylyl cyclase.
Adenyly Cyclase • The adenylyl cyclase causes the cell to convert ATP into cyclic AMP. • The cyclic AMP functions as a messenger, activating enzymes in the cytoplasm to carry out their normal functions • For example, when thyroid-stimulating hormone (TSH) attaches to the receptor sites in the thyroid gland, cyclic AMP is produced in thyroid cells. • The cyclic AMP in the thyroid cell activates enzymes, which begin producing thyroxine, a hormone that regulates metabolism.
The Pituitary Gland: the Master Gland • The pituitary gland exercises control over other endocrine glands. • This small sac-like structure is connected by a stalk to the hypothalamus, the area of the brain associated with homeostasis http://en.wikipedia.org/wiki/File:Pituitary_gland.png
http://bcs.whfreeman.com/thelifewire/content/chp42/4202s.swf
Pituitary Gland • The interaction between the nervous system and endocrine system is evident in this hypothalamus–pituitary complex • The pituitary gland produces and stores hormones • The hypothalamus stimulates the release of hormones by the pituitary gland by way of nerves.
Pituitary Gland • The pituitary gland is actually composed of two separate lobes: the posterior lobe and the anterior lobe • The posterior lobe of the pituitary stores and releases hormones such as antidiuretic hormone (ADH) and oxytocin, which have been produced by the hypothalamus http://www.neurosurgery.pitt.edu/minc/skullbase/pituitary/index.html
Pituitary Gland • The hormones travel by way of specialized nerve cells from the hypothalamus to the pituitary • The pituitary gland stores the hormones, releasing them into the blood when necessary
Pituitary Gland • The anterior lobe of the pituitary produces its own hormones • Like the posterior lobe, the anterior lobe is richly supplied with nerves from the hypothalamus • The hypothalamus regulates the release of hormones from the anterior pituitary http://ja.wikipedia.org/wiki/%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB:Pituitary_gland_et_vessel.jpg
Pituitary Gland • Most of the hormones produced by the hypothalamus activate specific cells in the pituitary, causing the release of pituitary hormones http://www.becomehealthynow.com/popups/pit_hypothalamus.htm
Hormones of the Pituitary • Various regulator hormones are stored in the anterior lobe of the pituitary gland. • Thyroid-stimulating hormone (TSH) • Reproductive stimulating hormones • Growth-stimulating hormones • Prolactin • Adrenocorticotropic hormone
http://kasper-achs-block3.wikispaces.com/General+Info+on+Glands+and+Hormoneshttp://kasper-achs-block3.wikispaces.com/General+Info+on+Glands+and+Hormones
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