KIN 292 1st Edition Lecture 2 Outline of Last Lecture I What is Physiology Chapter 1 1 Organization of the Human Body Outline of Current Lecture I Organization of the Human Body continued from Monday II Homeostasis A Central Organizing Principle of Physiology III The Diabetes Epidemic Current Lecture A simplified Body Plan Simplified to show relationships Wrong shape on purpose Missing parts Different cell types not shown Try to visualize relationships External and internal environments Separated by a continuous epithelial membrane barrier Filtration and reabsorption are specific terms for the kidneys External Environment External side of the epithelial body barrier Examples of external environment o Surroundings external to the skin o Air in the lungs o Food in the stomach o Urine in the bladder Body Fluids and Compartments Body is divided into compartments Compartments contain fluids Compartments are separated by epithelial membranes These 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 Membranes are semipermeable Transport occurs between compartments Fluid from one compartment is different from other The epithelial compartment keeps them divided and separate Total Body Water Consists of water and dissolved materials Includes solutions within cells and solutions surrounding cells Makes up about 60 of total body weight TBW is divided into intracellular and extracellular compartments ICF intracellular fluid Fluid inside cells cytoplasm ECF extracellular fluid Fluid outside cells but within body Is the internal environment Plasma surronds the blood cells Intersitial fluid surrounds all other cells External and Internal Exchange external plasma tissue fluid cell In Nutrients and oxygen Out Wastes and unneeded material TBW ICF ECF Amount of water in the body 10 gallons Homeostasis The maintenance of relatively constant conditions in the internal environment even under challenging conditions Many different components of the internal environment are regulated to remain constant under challenging conditions o Body Temperature 37 Celsius or 98 6 Fahrenheit Shivering when cold sweating when hot o Blood Glucose concentration 90 mg dl 5 million mol Constant blood glucose concentration o ATP concentration in muscles 5 million mol at rest or exercise ATP in muscles Requires organ systems integration Disruption of homeostasis is the basis for disease and death On a lighter note also fatigue Negative and Positive Feedback Negative feedback if a regulated variable increases the system responds by making it decrease if it decreases the system responds by making it increase o Most homeostatic regulatory mechanisms make adjustments only when they detect a difference between the actual value of the regulated variable and the desired variable set point Positive Feedback example o Negative feedback would be if your body produced less cortisol and in response your body produced more hypothalamus to maintain homeostasis o Positive feedback would be if your body produced more cortisol and in response your body signaled for more CRH to be produced because having more cortisol in the system is not bad for maintaining homeostasis Homeostasis Regulated variable That aspect which is maintained Examples Blood glucose concentration blood pH plasma levels of sodium room temp thermostat body temp Set point Normal desired value of a regulated variable Negative feedback If a regulated variable decreases the system responds to make it increase back to set point and vice versa Error signal Difference set point and current value of the regulated variable Negative Feedback Terms o Sensors Monitors the regulated variable Most are nerves Ex thermoreceptors chemoreceptors o Integrating centers IC Orchestrates an appropriate response to input signal from sensor decide on how to respond o Effectors body components receiving output signals from the IC on how to maintain or regain homeostasis Diabetes Epidemic Diabetes Greek origin meaning to siphon Mellitus Latin origin meaning honey sweet Diabetes mellitus is a metabolic disease disrupted glucose homeostasis o Blood glucose levels are elevated o Urine glucose are elevated o Plasma volumes are affected Signs and symptoms o Excessive thirst o Massive fluid loss excessive urination because high glucose in urine pulls water out of the body with it chap 4 for explanation Diabetes mellitus affects every organ system BMI Measures weight relative to height Used to define obesity Overweight BMI 25 29 Obese BMI 30 39 BMI of 30 is 30 lb overweight Morbid obesity BMI 40 more than 100 lb overweight Types of Diabetes Diabetes mellitus type 1 o Lack of insulin o Pancreas can t secrete insulin so they have to take dosages of it o Accounts for 5 10 of all diabetes mellitus cases Diabetes mellitus type 2 o Impaired response to normal insulin levels o Body rejects insulin Pre diabetes o Blood glucose 100 125 mg dL o High blood glucose o Affects 79 million Americans o Most likely to develop DM type 2 in 10 years Gestational diabetes o Subclass of DM type 2 o Affects 4 of pregnant women o May develop DM type 2 post pregnancy Diabetes insipidus o Insipid urine o Unrelated to DM o Affects antidiuretic hormone vasopressin aquaporin 2 system Diagnosing Diabetes o Fasting plasma glucose test 60 100 mg dL Normal 70 99 is range used by many others 100 125 mg dL Pre diabetes 125 mg dL Diabetes leads to eye disease kidney disease nerve damage and others o Oral glucose tolerance test plasma glucose 2 hrs after consuming 75 grams glucose DM slows glucose removal 139 mg dL Normal 140 199 mg dL Pre diabetes 200 mg dL Diabetes o Hemoglobin A1c level of Hb coated with sugar Marker of blood glucose for 2 3 mo life span of red blood cell Glucose only enters RBC when concentrations are high