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Features of Human Physiology: An Integrated Approach 8th Edition PDF: Following are the main features of this book given below; Special icons highlighting important clinical information High yield clinical pearls and clinical examples highlighting the relevance and application of physiologic concepts A full practice test organized by body system to allow either comprehensive testing or focused review.
Leave a Reply Cancel reply Your email address will not be published. Please share with your friends, let's read it!! Search Ebook here:. Book Preface The Eighth Edition of Human Physiology: An Integrated Approach builds upon the thorough coverage of integrative and molecular physiology topics that have always been the foundation of this book. Designed by readallbooks.
Download here Download Now here. Read Now Ads. Arnold Adolph Berthold was a German physiologist and zoologist, who, in , had a question about the function of the testes. He noticed that in castrated roosters that they did not have the same sexual behaviors as roosters with their testes intact. He decided to run an experiment on male roosters to examine this phenomenon.
He kept a group of roosters with their testes intact, and saw that they had normal sized wattles and combs secondary sexual organs , a normal crow, and normal sexual and aggressive behaviors.
He also had a group with their testes surgically removed, and noticed that their secondary sexual organs were decreased in size, had a weak crow, did not have sexual attraction towards females, and were not aggressive. He realized that this organ was essential for these behaviors, but he did now know how. To test this further, he removed one testis and placed it in the abdominal cavity.
The roosters acted and had normal physical anatomy. He was able to see that location of the testes do not matter. He then wanted to see if it was a genetic factor that was involved in the testes that provided these functions. He transplanted a testis from another rooster to a rooster with one testis removed, and saw that they had normal behavior and physical anatomy as well. Berthold determined that the location or genetic factors of the testes do not matter in relation to sexual organs and behaviors, but that some chemical in the testes being secreted is causing this phenomenon.
It was later identified that this factor was the hormone testosterone. William Bayliss and Ernest Starling, a physiologist and biologist, respectively, wanted to see if the nervous system had an impact on the digestive system.
They knew that the pancreas was involved in the secretion of digestive fluids after the passage of food from the stomach to the intestines, which they believed to be due to the nervous system. They cut the nerves to the pancreas in an animal model and discovered that it was not nerve impulses that controlled secretion from the pancreas. It was determined that a factor secreted from the intestines into the bloodstream was stimulating the pancreas to secrete digestive fluids.
This factor was named secretin: a hormone, although the term hormone was not coined until by Starling. Hormonal effects are dependent on where they are released, as they can be released in different manners. As hormones are defined functionally, not structurally, they may have diverse chemical structures.
Hormones occur in multicellular organisms plants, animals, fungi, brown algae and red algae. These compounds occur also in unicellular organisms, and may act as signaling molecules, [9] [10] but there is no consensus if, in this case, they can be called hormones. Compared with vertebrates, insects and crustaceans possess a number of structurally unusual hormones such as the juvenile hormone, a sesquiterpenoid.
Most hormones initiate a cellular response by initially binding to either cell membrane associated or intracellularreceptors. A cell may have several different receptor types that recognize the same hormone but activate different signal transduction pathways, or a cell may have several different receptors that recognize different hormones and activate the same biochemical pathway. Receptors for most peptide as well as many eicosanoid hormones are embedded in the plasma membrane at the surface of the cell and the majority of these receptors belong to the G protein-coupled receptor GPCR class of seven alpha helixtransmembrane proteins.
The interaction of hormone and receptor typically triggers a cascade of secondary effects within the cytoplasm of the cell, described as signal transduction, often involving phosphorylation or dephosphorylation of various other cytoplasmic proteins, changes in ion channel permeability, or increased concentrations of intracellular molecules that may act as secondary messengers e.
Some protein hormones also interact with intracellular receptors located in the cytoplasm or nucleus by an intracrine mechanism. For steroid or thyroid hormones, their receptors are located inside the cell within the cytoplasm of the target cell.
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