Kin 470 1st EditionExam # 1 Study Guide Lectures: 1 - 12What is homeostasis and hoe does it differ from steady state?Homeostasis- maintenance of a constant internal environment despite a changing external environment -relatively constant internal environmentStead State- balance between demands placed on body and the physiological response to those demands- a steady and unchanging level of some physiological variable-example: heart rateDifferences-homeostasis- used to denote a relatively constant and normal internal environment during resting conditions-steady state- does not mean that a physiological variable is at resting vales, but that the physiological variable is constant and unchangingexample of difference  body temperature during exercise---changes in core body temperature during 60 minutes of submax exercise in a thermoneutrual environment. * Temperature reaches a plateau (steady state) 40 minutes into exercise*the core temperature reaches a new and steady level within 40 minutes, this plateau of core temperature represents a steady state because temperature is constant* the constant temperature is above normal resting body temperature, thus it does not represent a true homeostatic conditionTake home- homeostasis is generally reserved for describing normal resting conditions and steady state is often applied to exercise, where the physiological variable in question is unchanging (e.g. Body temperature) but may not equal the homeostatic resting valueHomeostasis- does not remain absolutely constant; it varies around a set point (dynamic constancy)-example: arterial blood pressure, average 93, these oscillations are due to physiological variables related to negative feedback-pH-CO2-ATP in a cellHomeostasis Maintained- biological control system-series of interconnected components that work to maintain a physical or chemical parameter at a near constant value-receptor/ sensor: detects changes in internal environment-integrated/ control center: assesses input and triggers a response-effector: corrects disturbances to internal environmentStimulus  receptor  integrating center effector 1. stimulus excites receptor2. receptor signals the integrating center of a disturbance3. signals effector to correct disturbance4. effector corrects disturbance and removes stimulusCO2-Stimulus- high CO2 concentration in extracellular fluid-triggers receptor to send message to respiratory control center to increase breathing-respiratory muscles (effector) increase breathing and reduce CO2 concentration bringing the system back to homeostasisBlood pressure-Stimulus- heart action causes increasing blood pressure in blood vessels-Receptor- baroreceptors in carotid artery relay information to brain that blood pressure has increased-Integrator- brain signals heart to contract more slowly and with less force-Effector- blood pressure decreasesBlood glucose-Stimulus- eating cause blood glucose to rise-Receptor- pancreas sensing blood glucose rising -Integrator- pancreas needs to release insulin to lower BG-Effector- pancreas releases inulin and blood glucose decreases due to cellular uptake of glucose***failure of this process causes diabetesExample of positive feedback-labor contractions-- increase pressure on cervix stimulates sensory response--send a neural message to the brain control center-- response by triggering the hormone oxytocin from pituitary gland, promoting the increase of contractionsGain of a control systemGain= ratio of output to input* influences degree to which the control system can maintain homeostasis**system with large gain is more capable of maintaining homeostasisChallenge to homeostasis-exercise has the potential to disrupt many homeostatic variables-skeletal muscles produce large amounts of heat, overheating- heavy exercise results in large increase in muscle O2 requirements -large amounts of CO2 are produced as well as lactate* these changes must be countered by increases in breathing and blood flow to increase O2 delivery to the exercising muscles and remove metabolically produced CO2**best to do submax exercise in cool environments to help the body maintain steady state**Failure of biological control system:-heat stoke-hot and humid environments-unable to dissipate heat-core temperature rises-nausea, vomiting, fatigue, weakness, rapid pulse, confusion, seizure, coma-Diabetes-high blood glucose-High blood pressure-new set point for blood pressure-strains on other biological control systemsEXAMPLE- renal systemWhat do enzymes do in a reaction and what is common about their nomenclature?Catalysts that regulate the speed of reactions-lower the energy of activationFactors that regulate enzyme activity-temperature-pHNomenclautre of enzymes-“ase” suffix-reflex both the job category of the enzyme and the reaction it catalyzesEXAMPELS- oxidoreductaes- redox reactions: LDH-transferases- transfer elements: PFK-ATPase- hydrolyze ATP: myosin-myosinATPase- couples the hydrolysis of ATP to generation of force and motion in muscleWhat is endergonic reaction and how does it differ from an exergonic reaction?Endergonic reaction- require energy added to the reactants before the reaction can proceed, products have more energy than reactantsExergonic reaction- give off energy as a result of chemical processesWhat is meant by coupled reactions?Coupled reactions- reactions that are linked, with the liberation of free energy in one reaction being used to drive a second reaction-release of free energy in one reaction is used to drive the second reactionExample- oxidation reduction reactions*release of energy in an exergonic reaction drives an endergonic reactionWhat is gained and lost during a redox reaction? Oxidation-loss of electrons-molecule donates electrons (H+)-reducing agentReduction-gain of electrons-molecule accepts electrons (H+)-oxidizing agentWhat is the role of NADH in metabolism? Where is it made and what is the purpose of its oxidation?-Carrier molecule-used in glycolysistwo H must be removed from glyceraldehyde 3- phosphate, which combines with inorganic phosphate to form 1,3- bipohsphogylcerate- takes 2 H from GP3 to add P and create 1,3 bi- in order to do that NAD+ needs to remove the 2 H - becomes NADH+ + H+-the H acceptor in this reaction is NAD and converted to NADHNAD is restored in two ways1. if here is sufficient oxygen, the hydrogen from NADH can be shuttled into the mitochondria of the cell and can contribute to the aerobic production of ATP2. if