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Physiology 2130 - Modules 1-9 - NOTES.pdf

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Biology 2290F/G
Media Phys3.0

By Moe Elbagdady Module One Introduction to Physiology 11ObjectivesDefine PhysiologyDefine homeostasis Describe negative feedback control systemsList levels of organization in human body 12IntroductionKey Problem for BodyCells to surround themselves with barriers that allows wanted stuff to pass in and unwanted stuff to pass outTerms o Internal Environment o External environment o HomeostasisImportance of Negative feedback control systems and their involvement in regulating internal environmentPhysiologyo Study of living organism functions o Explores the mechanisms by which the organisms control their internal environment regardless of what happens in outside external environment o Explain physical and chemical factors responsible for both function and disease pathology 13HomeostasisInternal Environment fluids in which cells of body live in o Interstitial between fluid Tissue fluid the extracellular fluid bathing most tissues excluding the fluid within the lymph and blood vessels Found in the interstitial spaces It is the main component of Extracellular Fluid all body fluid outside of cells which also includes plasma and transcellular fluid portion of total body water contained within epithelial lined spaces Smallest component of extracellular fluid o Blood plasma the yellow or grayyellow proteincontaining fluid portion of blood in which the blood cells and platelets are normally suspendedExternal Environment region outside body o Also includes spacecontents of digestive repertory and urogenital tracks organ system of the reproductive organs and the urinary systemHomeostasis maintenance of relatively stable conditions within internal environment regardless external environment events o Allows our bodies to maintain a stable internal environment so cells can function regardless of what is happening in the external environment o Maintains homeostasis using Negative and Positive Feedback control mechanisms 15Negative Feedback ControlsNegative feedback controls Controlled variable eventually shuts off its own production o Examples maintaining body temperatures maintaining fluid volumes o All operate same wayContain Set point control center aka integrator effector controlled variable and sensor aka receptor Simple Example 16Example House o Set PointHeat of 20 CPredetermined Set Point to be maintained in environment o SensorControl centerThermostat usually not both Sensor Senses alterations in environmental conditionsControl center Controls Effector which then controlled by sensor ie Sensor turns off Control center when condition is achieved o EffectorFurnace effects environment to achieve pointEffector affects altered environmental conditions to achieve Set point Body Example 17Example Body Temperature o Set PointBody Heat of 37 CPredetermined Set Point to be maintained in body o SensorNervous system sensors detect heat changes Senses change in body temperatureSignals control center ie brain part hypothalamus o Control centerRegion in brain called the HypothalamusControl center notices temperature differenceActivates organssystems ie effectorControl center Controls Effector and Control center is controlled by sensor ie Sensor turns off Control center when condition is achieved o EffectorOrgansBodily Systems effects environment to achieve set pointGenerates heat controlled variable by shivering and conserving heat by decreasing blood flow to skinOnce set point achieved control center stops the shivering and would return the blood flow to the extremitiesIf body temperature increased above the set point Hypothalamus control center would signal blood vessels in the skin to dilate and sweat glands to sweat Heat dissipates and body temperature drops to normalEffector affects altered environmental conditions to achieve a control variable value Control VariableBody Heat 18Positive Feedback Controls feed forward systemsThe controlled variable actually stimulates its own productionPositive feedback systems are selfamplifying mechanisms that can produce a very rapid change in a physiological system The controlled variable is detected by the sensor that signals the control center to activate the effector to produce more of the controlled variable In this way large amounts of the controlled variable are produced very rapidly o Examples Generation of the action potential in nerve cells and the surge of luteinizing hormone that causes the ovulation of the egg from the ovary 19Negative and Positive Feedback Control SystemsAll body systems use negative or positive feedback to regulate functions and maintain homeostasiso These feedback mechanisms rely on two control systems to function properly the nervous system and the endocrine systemNervous system brain spinal cord and all of the nerves is adapted for rapid communication through complex system of neurons and nerves Endocrine system responds slower communicating by release and distribution of hormones in blood 110The Bodys Structural HierarchyAtoms make up molecules Molecules make up macromolecules which form cellular organelles Almost all cells of the body contain similar organelles like the nucleus the cell membrane proteins and so on Some cells have taken these basic structures and have turned them into highly specialized structures giving each cell specific purposeo Example muscle cells contain large quantities of special proteins that cause the muscle to contract Tissue Groups of cells with all the same specializationo Example muscle tissue is specialized because it contains cells that can contract Organs Two or more types of tissues combined to form a complex functional unito Example the heart is composed of connective tissue muscle tissue and specialized conducting tissue Organ systems when several organs cooperate for a common function Cardiovascular system combined blood vessels veins arteries and capillaries and the heart Organism when all of the organ systems are grouped together 111A Quick Look BackIn order for all of the cells and organ systems to function properly the internal environment of the body must be maintained at relatively stable conditions regardless of what is happening in the external environment o Maintaining a relatively constant body temperature water balance salt concentrations etc The body achieves this by detecting changes then through negative feedback control systems correcting the change Each organ system is made up of different organs working together for a common function Each organ is made up of several different types of tissues while each tissue is made up of cells with similar specializationso Fluid and ion composition inside of the cell is different from that outside and how these differences come about
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