KIN 292 1st Edition Lecture 15 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 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 PostabsorptiveStates V 21 5 Regulation of Absorptive and Postabsorptive Metabolism Outline of Current Lecture I 21 6 Thermoregulation continued II 21 7 Hormonal Regulation of Growth III 21 8 Thyroid Hormones IV 21 9 Glucocorticoids Current Lecture 21 6 Thermoregulation Temperature Balance o Core body temperature o Humans 37 Degrees C 98 6 Degrees F Hypothermia decrease in body temperature Hyperthermia increase in body temperature o Temperature 41 Degrees C is dangerous o Temperature 43 Degrees C is deadly 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 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 TNZ a temperature range in which a standard healthy adult can maintain normal body temperature without needing to use energy above and beyond normal basal metabolic rate Environmental temperature range 25 30 C 77 86 F for a naked man standing upright in still air With clothing radiation and convection losses dramatically reduced lowering the TNZ Within TNZ 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 Heat generation in a cold environment Below the thermo neutral zone Vasoconstriction alone cannot maintain proper core body temperature Heat generating mechanisms Shivering thermogenesis involuntary contractions of skeletal musclesuse energy and generate heat Can raise metabolic rate as much as 5 fold Only effective mechanism in modern humans Non shivering thermogenesis from brown adipose tissue found ininfants and some animals Not so much for us adults Piloerection goose bumps animals and cavemen Heat loss in a warm environment Above the thermo neutral zone Vasodilation alone cannot maintain proper core body temperature Increased production of sweat primarily from eccrine sweat glands Much less contribution from apocrine glans located in arm pits and genital areas Power of sweating At rest naked person can maintain 37 degreesC core at 54 60 degrees C 130 140 degrees F Power of SweatingThis will be on the test I am emphasizing this slide He said that on the test he will give us an equation to work out based on this Each 1 ml of sweat evaporation 0 6 kcal body heat loss At rest human heat production about 1 2 kcal min 100W light Counter with 2 ml sweat evaporation 2 x 0 6 1 2 Maximum sweat rate is about 30 ml min varies considerably or about 18 kcal heat removed min Heat production at maximum aerobic exercise is slightly more What is the impact of this Sweating Good and Bad Good Primary means to dissipate heat during exercise or very hot environments Bad Water loss can lead to dehydration which adversely affects blood volume and blood flow distribution Water for sweat comes from all compartments in the body Water Loss in the Heat Dehydration Amount of water loss directly proportional to the environmental conditionsand the length intensity of physical activity Consequences of Water loss body wt 1 2 Impaired thermoregulation 3 Reduced endurance 4 6 possible heat cramps 6 heat exhaustion heat stroke coma Bottom line stay hydrated Preventing dehydration saves lives Clinical Connections Heat Exhaustion and Heat Stroke page10 Maintaining hydration can prevent these Heat Exhaustion Profuse sweating Reduced blood volume Blood flow to skin blood pressure blood flow to brain Negative feedback Temperature still normal Dizziness fainting Flushed and wet Heat Stroke No sweating Reduced blood volume Blood flow to skin blood pressure blood flow to brain feedback IC damage Temperature elevated Delirium Flushed and dry Alterations in the Set Point for Thermoregulation Fever Rise in core body temperature set point Accompanies infection White blood cells secrete pyroxenes Body temperature set point increases Fever enhances immune responses Example of the fact that set point of some regulated variables can be changed for good reasons 21 7 Back to hormones Stanfield will be focusing on hormones affecting growth increasing or inhibiting growth In our test the term growth usually refers to bodily changes accompanying increases in height But remember that many hormones also have a primary responsibility for glucose homeostasis We already discussed insulin and glucagon Table21 4 lists the other main ones Note how many hormones are involved in plasma glucose homeostasis Insulin actions regarding plasma glucose lipolysis are opposite all other hormones Thyroid hormone changes metabolic rate which indirectly affects CBH lipid metabolism Growth hormone most important one for height bone growth NFL Union Agree to New Drug Policy HGH Testing NEW YORK Sep 17 2014 4 58 PM ET The NFL finally will have HGH testing But Growth hormone is not just for height Also produces hypertrophy of muscle cells via increased AA uptake and protein synthesis in muscle and decreases fat by increasing use of fat for metabolic fuel Hypertrophy Increase cell size Hyperplasia Increase cell number Insulin like Growth Factors IGFs peptides with some structural similarity to insulin GH stimulates IGF release from liver and other cells IGF 1 after birth IGF 2 during gestation period