KIN 292 1st Edition Lecture 14 These are the notes from Professor Starnes lecture of Clinical Human Physiology These come from the slideshows provided by the professor and include extra notes and explanations Highlighted or bolded information are things that I believe to be information that is important to look over multiple times The notes in red are my personal additions and quotes of Professor Starnes from the class lecture Outline of Last Lecture I 6 1 Primary Endocrine Organs II 6 2 secondary endocrine organs III 6 3 hormone actions at the target cell IV 6 4 Abnormal Secretion of Hormones V 6 5 Hormone interaction Outline of Current Lecture I 21 1 An Overview of Whole Body Metabolism review II 21 2 Energy Intake Utilization and Storage review III 21 3 Energy Balance IV 21 4 Energy Metabolism During the Absorptive and Postabsorptive States V 21 5 Regulation of Absorptive and Postabsorptive Metabolism Current Lecture 21 1 An Overview of Whole Body Metabolism review of material we have already covered Anabolism Biomolecules that provide energy are also used in large molecule synthesis Depends on body needs Mechanisms exist to regulate pathways Regulation of metabolic pathways Regulation of enzymes Concentration and activity of enzymes Compartmentation Cellular tissue and organ 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 21 2 Energy Intake Utilization and Storage review of material we have already covered Nutrients Carbohydrates glucose Proteins amino acids Lipids lipoproteins Following intake nutrients can fulfill several functions Catabolized for energy Act as substrates for new molecules Stored for energy glycogen and fat 21 3 Energy Balance Energy input nutrients energy output Regulated by endocrine system Metabolic Rate the energy output component Energy expended per unit time Basal metabolic rate BMR rate of energy expenditure of a person awake resting lying down who has fasted for 12 hours at its lowest Represents the minimum energy expenditure necessary to maintain body functions lowest energy output Metabolic rate increases with increases in activity when you re eating Metabolism During the Absorptive Postabsorptive States Absorptive Energy input output Positive energy balance Glucose primary energy source for cells Excess nutrients taken up stored as either glycogen liver and muscle or triglycerides adipose tissue Postabsorptive Energy input output Negative energy balance Glucose is spared for nervous system not very much glucose in body so it must be spared Other tissues use fatty acids or other stored sources for energy Positive energy balance leads to storage of glycogen and fat Recall this figure from ch 3 If you consume more protein than needed for protein synthesis or morecarbs than can be stored as glycogen the excess will be converted to fat Note central location of acetyl CoA all nutrients can produce it and use it for synthesis Acetyl CoA can go into the mitochondria or be used by the mitochondria View table 21 2 Energy Stores in a Healthy Approximately 154 lb Man Total glycogen stored approximately 500 grams 2000 kcal 21 5 Regulation of Absorptive and Postabsorptive Metabolism Mainly regulated by 2 antagonistic hormones Insulin in absorptive state in postabsorptive state Glucagon in absorptive state in postabsorptive state Negative feedback from plasma glucose most important regulator ofthese hormones Other less important regulators Epinephrine and Sympathetic nervous system Plasma glucose stimulates these and they act to inhibit insulinsecretion and stimulate glucagon secretion View table 21 3 Factors Affecting Insulin and Glucagon Release Figure 21 5 Actions of insulin on target tissues Returns blood glucose to homeostasis by promoting its uptake by body cells Promotes synthesis of energy storage molecules anabolic reactions Peptide hormone secreted from beta cells of the islets of Langerhans in the pancreas It s all about timing He gave the example of post workout drinks and how they are time specific to be effective Figure 21 6 How glucose stimulates cell to release insulin physiology in action Summary of glucose stimulating insulin secretion previous slide Glucose Enters cells by facilitated diffusion through GLUT2 Catabolized to ATP ATP closes K channels beta cell depolarizes with less K moving out Ca2 channels open Secretion of insulin Figure 21 7 Actions of glucagon on target tissues Goal glucose in blood by gluconeogenesis and shifting energy use to other stored molecules catabolic primarily fat Diabetes Mellitus Energy metabolism impaired Insulin deficiency type 1 diabetes mellitus Deficient insulin response type 2 diabetes mellitus Primary sign hyperglycemia Normally suppresses glucagon release Not so in diabetes Decreased insulin Decreases betacells permeability to glucose Triggers a falsely low glucose level beta cells increase glucagon release How Insulin gets glucose into cells http www youtube com watch v hwE1osnb5qc This excellent 5 minute video covers insulin receptor binding GLUT4 movement induced by insulin and by exercise and disruptions in insulin signaling associated with diabetes 21 6 Thermoregulation Temperature Balance Core body temperature Humans 37 degrees C 98 6 degrees F Hypothermia decrease in body temperature Hyperthermia increase in body temperature Temperature 41 degrees C is dangerous Temperature 43 degrees C is deadly Mechanisms of Heat Transfer Between the Body and the External Environment Radiation heat gain or loss and Thermal energy through electromagnetic waves Conduction and Thermal energy through contact Convection and Heat transfer by movement of fluid or air Evaporation heat loss only Insensible water loss Sweating Regulation of Body Temperature Receptors thermo receptors neurons Central found in CNS hypothalamus Peripheral found in PNS mainly skin Integrating center Thermoregulatory center in hypothalamus Effectors Sweat glands Muscles Skeletal muscles Smooth muscle of cutaneous skin blood vessels Regulation of Body Temperature Thermo neutral zone Environmental temperature range 25 30 C Cutaneous blood flow changes enough to regulate body temperature Increasing body temperature Cutaneous vasodilation Increased blood flow to skin causing heat loss Decreasing body temperature Cutaneous vasoconstriction Decreased blood flow to skin causing heat retention Regulation of Body Temperature Heat generation in a