physiology

• Physiology, from the Greek physis = nature and logos = study, is the study of biological function - how the body works, from molecular mechanisms within cells to the actions of tissues, organs, and systems, and how the organism as a whole accomplishes particular tasks essential for life.
• Physiology aims to understand the mechanisms of living - how living things work.
• Aristotle, from Greece, speculated about body function but was not a doer.
• William Harvey, from England, demonstrated that the heart pumps through a closed system of vessels.
• Claude Bernard, from France, observed that the internal environment (milieu interieur) stays relatively constant despite changes occurring.
• Walter Cannon, from the US, coined the term, homeostasis, to describe the internal consistency of the body.
• Maintenance of homeostasis is essential for survival and normal functioning of cells.
• Feedback Loops involve a Sensor that detects deviation from set point, an Integrating center that determines the response, and an Effector that produces the response.
• Neuroglia: Supporting cells in nervous tissue.
• Homeostasis is a state of dynamic constancy of the internal environment, maintained by negative feedback loops.
• Positive feedback enhances or accelerates output created by an activated stimulus, for example, platelet aggregation and accumulation in response to injury, and the birth of a human infant.
• The nervous and endocrine systems provide extrinsic regulation of other body systems and act to maintain homeostasis.
• Homeostatically Regulated Factors include Concentration of nutrients, Concentration of O2 and CO2, Concentration of waste products, pH, Concentrations of water, salt, and other electrolytes, Volume and pressure, and Temperature.
• Negative feedback brings a system back to its level of normal functioning, for example, adjustments of blood pressure, metabolism, and body temperature.
• Regulation of processes within organs can occur in two ways: Intrinsically, where cells within the organ sense a change and signal to neighboring cells to respond appropriately, and Extrinsically, where the brain (or other organs) regulates an organ using the endocrine or nervous system.
• Nervous tissue contains two categories of cells: Neurons and Supporting cells (Neuroglia).
• Neuron: The main cell type in nervous tissue.
• Galen, also known as Claudius Galenius, is known as the “founder of experimental physiology”.
• Neurophysiology is a branch of physiology.
• Neuroscience, or neurobiology, is the scientific study of the nervous system.
• The Nervous System is the master controlling and communicating system of the body.
• The central nervous system, the main data center of the body, includes the brain and spinal cord.
• The peripheral nervous system includes all of the neurons that sense and communicate data to the central nervous system.
• Nervous tissue is one of four major classes of tissues and makes up the central nervous system and the peripheral nervous system.