L8chemicalsignals_sp10

L8chemicalsignals_sp10 - Lecture 8; various chapters...

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Lecture 8; various chapters Lecture Outline Chemical Signals I. Chemical Signals in Animals: Overview In response to sights, sounds, and other sensory stimuli, an animal’s nervous system sends rapid messages to precise locations in the body. Frequently these messages result in muscle contractions and movement. As conditions inside and outside the animal change, however, cells in the central nervous system (CNS) or cells in a specialized group of organs called the endocrine system may trigger the release of molecules that produce longer-term responses in a broad range of tissues and organs. A chemical signal that circulates through the body fluids and affects distant target cells is called a hormone. The word hormone comes from the Greek word “to excite.” Animal hormones are present in tiny concentrations but have huge effects on their target cells. Unlike action potentials which are electrical impulses that have a short- term effect on a single cell or on a small population of adjacent cells, the messages that hormones carry are received by many different cells and have a relatively long-lasting effect. In combination, electrical and chemical signals allow animals to coordinate the activities of cells throughout the body. They are the mechanism responsible for maintaining trillions of cells as the integrated unit we call an individual. There are six categories of chemical signals in animals:
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Lecture 8; various chapters Lecture Outline II. The Vertebrate Endocrine System: Hormones are secreted by endocrine glands. Hormones share various characteristics •All hormones are organic compounds •All hormon es are secreted from the cells where they are synthesized •All hormones act on target cells remote from their point of origin •All hormones are present in extremely small concentrations yet have large effects.
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Lecture 8; various chapters Lecture Outline
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Lecture 8; various chapters Lecture Outline Posterior Pituitary Hormones: Anterior Pituitary Hormones:
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Lecture 8; various chapters Lecture Outline III. Regulation of the Kidneys Disorders: Diabetes insipidus: “Diabetes” means overflow and “insipidus” means tasteless. This
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L8chemicalsignals_sp10 - Lecture 8; various chapters...

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