BCMB 230 1st Edition Lecture 1 Outline of Last Lecture I.NoneOutline of Current Lecture I.The BasicsII.HomeostasisIII.Feedback SystemsIV.Components of Homeostatic Control SystemsV.Processes Related to HomeostasisCurrent LectureI. The BasicsPhysiology- the study of how the body works (functions and processes)-often paired with Anatomy, which is the study of structurePhysiology includes: -the study of individual molecules (molecular level): looking at protein shape, how it works, what it influences, and how changing the shape works-the study of complex processes that depend on the integrated functions of many organsin the body (ex. heart, kidneys, and several glands all work together to cause the excretion of more sodium ions in the urine when a person has eaten salty food)How the body is organized:-cells: simplest structural units (built by molecules) into which a complex multi-cellular organismcan be divided and still retain the functions characteristic of life-Four major categories of Types of Function that cells can perform (are specialized for):-muscle cells-neurons-epithelial cells-connective tissue-tissues: formed by differentiated cells with similar properties-Four general types of tissues:-muscle tissue-nervous tissue-epithelial tissue-connective tissueThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.-the term “tissue” is also used to denote the general cellular fabric of any organ or structure (ex. kidney tissue)-tissues can also build a functional unit-functional unit: when organs are organized into small, similar subunits that perform the function of the organ-ex. functional unit of the kidney is the nephron; total production of urine by the kidneysis the sum of the amounts produced by the 2 million or so individual nephrons-organ: one type of tissue combines with other types of tissues-organ systems: when organs work together to perform an overall function-then there are multi-organ processes that lead to a total organismII. HomeostasisInternal environment of the body- refers to the fluids that surround cells and exist in bloodHomeostasis- relatively stable condition of internal environment that results from regulatory system actions-characteristics of homeostatic control systems: the activities of the cells, tissues, and organs must be regulated and integrated with each other so that any change in the extracellular fluid initiates a reaction to correct the change-not always the same, there are variations depending on the variableIII. Feedback SystemsMechanisms to promote idea of homeostasis-cellular processes are related by feedbackNegative feedback- characteristic of control systems in which system’s response opposes the original change in the system; have physiological process-enzyme sequence; end productacts to reduce activity of earlier step (end product inhibition); controls production of active product; acts to provide us with relatively stable state (if you have too much of something, stop making it); providing for homeostasis-body maintains steady internal environment-plays a vital part in the checks and balances on most physiological variables-Examples:-Figure 1.4—hypothetical example of negative feedback -blood pressure-temperature-plasma/blood pH (very acidic)Positive Feedback-characteristic of control systems in which an initial disturbance sets off train of events that increase the disturbance even further; process produces something- goes back to accelerate process which leads to an “explosive” system; creates more of active product-counter to the principle of homeostasis because it has no obvious means of stopping-much less common in nature than negative feedback-Examples:-ex. Blood clotting-produce protein to prevent blood loss, also helps keep homeostasis-ex. Contractions during labor-stimulates another contraction; builds until deliveryFeed Forward- aspect of some control systems that allows system to anticipate changes in a regulated variable; improves the speed of the body’s homeostatic responses and reduces the amount of deviation from the set point (maintain homeostasis by minimizing changes to the body)-Examples-moving from a warm area to a colder one-salivating when smelling good foodIV. Components of Homeostatic Control SystemsSet Point- “operating point”; steady-state value maintained by homeostatic control system (doesn’t have to be exact) -gives predicted value-ex. If temperature not where expected, then something is wrong (fever infection)-how close around set point depends on what you are measuringReflex-a specific, involuntary, unpremeditated, unlearned, “built-in” response to a particular stimulus-check Figure 1.5-predictable response to a stimulus-receptor- detects environmental change and translates stimulus to something body recognizes-integrating center-(integrator) brain region that compares the actual value of a variable (ex. body temperature) to a set point-afferent pathway- (“to carry to”) component that transmits information from receptor to integrating center-effector- cell or cell collection whose change in activity constitutes the response in a control system-efferent pathway- (“to carry away from”) component that transmits information from integrating center to effector-negative feedback will influence a stimulus (ex. nervous system)Hormone-type of chemical messenger secreted into the blood by cells of the endocrine systemLocal homeostatic responses-response acting in immediate vicinity of a stimulus, without nervesor hormones, and having net effect of counteracting stimulusThree types of reflex: endocrine reflex, nervous reflex, or neuroendocrine reflexExtrinsic-outside of systemIntrinsic-inside of systemEx. Control of stomach- (nervous system, hormones—extrinsic; local chemical messengers—intrinsic)Nerves and hormones=extrinsic=endocrineLocal=intrinsic=paracrine-effect on next-door-neighbor=autocrine-cell releases chemical messenger—acts on itselfParacrine substances/agents- chemical messengers involved in local communication between cells; generally inactivated rapidly by locally existing enzymes so that they do not enter the bloodstream in large quantitiesAutocrine substances/agents- when a chemical messenger is secreted by a cell into the extracellular fluid and then acts upon the very cell that secreted itV. Processes Related to HomeostasisAdaption-change in