311DCh45 - Ch 45 pg 975-994 Hormone chemical signal that is secreted into the circulatory system and communicates regulatory messages within the

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Ch. 45 pg. 975-994 Hormone – chemical signal that is secreted into the circulatory system and communicates regulatory messages within the body Endocrine system – all of an animal’s hormone secreting cells Endocrine glands – hormone secreting organs; ductless glands because they secrete their chemical messengers directly into extracellular fluid; chemicals then diffuse into the circulation Neurosecretory cells – release hormones into the blood; contained in hypothalamus Negative feedback – effector response reduces the initial stimulus and the response ceases Reception – occurs when the signal molecule binds to a specific receptor protein in or on the target cell Signal transduction – binding of signal molecule to a receptor protein triggers events within the target cell Response – result; change in cell’s behavior Signal Transduction Pathway – series of changes in cellular proteins that converts an extracellular chemical signal to a specific intracellular response; activation of enzyme, change in uptake or secretion of specific molecules, or rearrangement of the cytoskeleton Paracrine signaling – local regulators convey messages between neighboring cells Cytokines – play a role in immune responses Growth factors – stimulate cell proliferation and differentiation Nitric Oxide – when blood oxygen level falls, endothelial cells in blood vessel walls synthesize and release NO; NO activates an enzyme that relaxes the neighboring smooth muscle cells which dilates the vessels and improves blood flow to tissues Prostaglandins – modified fatty acids derived from lipids in the plasma membrane; discovered in prostate gland secretions that contribute to semen; regulate nearby cells depending on the tissue; stimulate smooth muscles of uterine wall to contract so that sperm reach an egg Hypothalamus – integrates the vertebrate endocrine and nervous systems; receives information from nerves throughout the body and from other parts of the brain and
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/01/2011 for the course BIO 311D taught by Professor Reichler during the Spring '08 term at University of Texas at Austin.

Page1 / 3

311DCh45 - Ch 45 pg 975-994 Hormone chemical signal that is secreted into the circulatory system and communicates regulatory messages within the

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online