KIN 292 1st Edition Lecture 14These 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 OrgansII. 6.2- secondary endocrine organsIII. 6.3- hormone actions at the target cellIV. 6.4- Abnormal Secretion of HormonesV. 6.5- Hormone interaction Outline of Current Lecture I. 21.1 An Overview of Whole-Body Metabolism - reviewII. 21.2 Energy Intake, Utilization, and Storage - reviewIII. 21.3 Energy BalanceIV. 21.4 Energy Metabolism During the Absorptive and Postabsorptive StatesV. 21.5 Regulation of Absorptive and Postabsorptive MetabolismCurrent Lecture21.1 An Overview of Whole-Body Metabolism review of material we have already coveredAnabolism•Biomolecules that provide energy are also used in large-moleculesynthesis•Depends on body needs- Mechanisms exist to regulate pathwaysRegulation of metabolic pathways•Regulation of enzymes•Concentration and activity of enzymes•Compartmentation•Cellular, tissue, and organThese 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 systemMetabolic 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 energyPositive 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 mitochondriaView 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 secretionView 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 βcell to release insulin – physiology in actionSummary 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 insulinFigure 21.7 Actions of glucagon on target tissues. Goal: ↑glucose in blood by ↑ gluconeogenesis and shifting energy use to other stored molecules (catabolic), primarily fatDiabetes 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 releaseHow Insulin gets glucose into cellshttp://www.youtube.com/watch?v=hwE1osnb5qcThis excellent 5 minute video covers insulin receptor binding, GLUT4 movement induced by insulin and by exercise, and disruptions in insulin signaling associated with diabetes21.6 ThermoregulationTemperature Balance-Core body temperature Humans: 37 degrees C (98.6 degrees F)Hypothermia: decrease in body temperatureHyperthermia: increase in body temperatureTemperature > 41 degrees C is dangerousTemperature > 43 degrees C is deadlyMechanisms 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•SweatingRegulation 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 vesselsRegulation of Body Temperature•Thermo neutral zone•Environmental