Physiology
Physiology, study of the physical and chemical processes that take place in living organisms during the performance of life functions. It is concerned with such basic activities as reproduction, growth, metabolism, excitation, and contraction as they are carried out within the fine structure, the cells, tissues, organs, and organ systems of the body.
Physiology is intimately linked with anatomy and was historically considered a part of medicine. Its emphasis on investigating biological mechanisms with the tools of physics and chemistry made physiology a distinct discipline in the 19th century; the tendency today, however, is toward a fragmentation and merging with the many specialized branches of the life sciences. Three broad divisions are recognized: general physiology, concerned with basic processes common to all life forms; the physiology and functional anatomy of humans and other animals, including pathology and comparative studies; and plant physiology, which includes photosynthesis and other processes pertinent to plant life.
The first studies in animal physiology were probably undertaken about 300 bc by the Alexandrian physician Herophilus, who reportedly vivisected the bodies of criminals. For about 1900 years thereafter, few physiological studies were performed.
Modern animal physiology dates from the discovery of the circulation of the blood by the English physician William Harvey in 1616. Shortly thereafter, the Flemish chemist Jan Baptista van Helmont developed the concept of gases and suggested the use of alkalies in treating digestive disturbances; the Italian biophysicist Giovanni Alfonso Borelli published studies of animal motion, suggesting that the basis of muscle contraction lay in the muscle fibers; the Dutch microscopist Antoni van Leeuwenhoek gave the first descriptions of red blood cells and spermatozoa; and the Italian histologist Marcello Malpighi demonstrated the existence of capillaries and studied the physiology of the kidney, liver, and spleen. During the second half of the century the study of glands was initiated by the English physician Thomas Wharton, who demonstrated salivary secretion, and by the Danish anatomist Nicolaus Steno, who demonstrated the secretions of the tear glands and salivary glands. The Dutch physician Regnier de Graaf furthered glandular study by his discovery of the follicles in the ovary; he also performed studies on pancreatic juices and bile. The English physician Richard Lower was the first to transfuse blood (see Blood Tansfusion) from one animal to another, and the French physician Jean Baptiste Denis first gave a human being a successful blood transfusion.
Physiology is intimately linked with anatomy and was historically considered a part of medicine. Its emphasis on investigating biological mechanisms with the tools of physics and chemistry made physiology a distinct discipline in the 19th century; the tendency today, however, is toward a fragmentation and merging with the many specialized branches of the life sciences. Three broad divisions are recognized: general physiology, concerned with basic processes common to all life forms; the physiology and functional anatomy of humans and other animals, including pathology and comparative studies; and plant physiology, which includes photosynthesis and other processes pertinent to plant life.
The first studies in animal physiology were probably undertaken about 300 bc by the Alexandrian physician Herophilus, who reportedly vivisected the bodies of criminals. For about 1900 years thereafter, few physiological studies were performed.
Modern animal physiology dates from the discovery of the circulation of the blood by the English physician William Harvey in 1616. Shortly thereafter, the Flemish chemist Jan Baptista van Helmont developed the concept of gases and suggested the use of alkalies in treating digestive disturbances; the Italian biophysicist Giovanni Alfonso Borelli published studies of animal motion, suggesting that the basis of muscle contraction lay in the muscle fibers; the Dutch microscopist Antoni van Leeuwenhoek gave the first descriptions of red blood cells and spermatozoa; and the Italian histologist Marcello Malpighi demonstrated the existence of capillaries and studied the physiology of the kidney, liver, and spleen. During the second half of the century the study of glands was initiated by the English physician Thomas Wharton, who demonstrated salivary secretion, and by the Danish anatomist Nicolaus Steno, who demonstrated the secretions of the tear glands and salivary glands. The Dutch physician Regnier de Graaf furthered glandular study by his discovery of the follicles in the ovary; he also performed studies on pancreatic juices and bile. The English physician Richard Lower was the first to transfuse blood (see Blood Tansfusion) from one animal to another, and the French physician Jean Baptiste Denis first gave a human being a successful blood transfusion.
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