1. For 1QQs Last name, First name Question # a b c d e

2. Announcements Turn in Personal Information (place on Piano.) Reading and Chapter Questions –Will finish Thermoregulation Today and –Glucose Homeostasis on Monday –By Monday,complete all Glucose Homeostasis Questions

3. 1QQ Sample Questions Name on top edge, back side of paper Answer on blank side of paper. Answer one of the following: 1.The San people of Botswana were clothing made of tanned animal skins. A) What would be the preferred type of clothing for their hot desert environment, b) why would it be preferred (think heat exchange mechanisms) and c) why do you suppose they don’t wear what would be preferred? 2.What is the difference between a reflex and a negative feedback loop?

4. 1QQ # 2 for 8:30 Name on top edge, back side of paper Answer on blank side of paper. 1.For the negative feedback loop for thermoregulation a)The hypothalmus is an afferent pathway b)Somatic nerves are the efferent pathway to sweat glands c)Skeletal muscle tone would be increased as a response to a drop in core body temperature d)Peripheral nerves are the afferent pathway that convey skin temperature information e)Cutaneous arterioles would dilate in response to a drop in core body temperature.

5. 1QQ # 2 for 9:30 Name on top edge, back side of paper Answer on blank side of paper. 1.For the negative feedback loop for thermoregulation a)The hypothalmus is an efferent pathway b)Somatic nerves are the efferent pathway to skeletal muscles c)Skeletal muscle tone would be decreased as a response to a drop in core body temperature d)Peripheral nerves are the afferent pathway that convey skin temperature information e)Sympathetic nerves would lead to constriction of cutaneous arterioles in response to a drop in core body temperature.

7. Add covers or clothing or enter sleeping bag Skin tempAnd Core body temp Detected by thermoreceptors in skin Activity in sensory nerves Hypothalamus Sympathetic nerves Relax smooth muscle in cutaneous arterioles Blood flow to skin Heat loss by conduction & radiation Somatic nerves Muscle tone Heat production Sweat Glands Sweat production Evaporative heat loss Core temp. Voluntary behaviors Remove covers Turn on fan, etc via Heat loss Cerebral cortex Conductive heat loss Radiative heat loss Convective heat loss Central thermoreceptors Skeletal Muscles Somatic nerves

8. ~37 o C Be able to explain the physiology in each of these situations with a detailed diagram of negative feedback responses and the modes of heat exchange involved.

9. Which roofers are most appropriately dressed for the job? Red shirts No shirts 1 st day on the job –Increase body temp….. Delayed sweating via negative feedback 10 th day on the job –Sweating precedes changes in core body temperature –and sweating is increased –And salt loss in sweat is minimized Responses begin even before core temperature increases! Not just negative feedback, this is Feedforward (requires experience). FF is evidence of Acclimitization. Advantage of feedforward: anticipates disruption and minimizes fluctuation from the set point.

10. Acclimatization & Feedforward Deviations from set point are minimized Learned (by experience) Anticipates changes of a physiological parameter Response begins before there is a change in the physiological variable Minimizes fluctuations

11. Failure of 1. Brain function & 2. Heat loss mechanisms Increase Body Temp. Increase cell metabolism Sympathetic outflow Blood Pressure Blood Flow to brain Disrupted function of neurons Cutaneous vasodilation Heat Stroke Sweating Blood volume Excessive Sweating Massive Cutaneous Vasodilation Treating Heat Stroke

12. Positive feedback Inherently unstable Examples of Positive Feedback in Physiology –Heat stroke –formation of blood clot –menstrual cycling of female sex hormone concentrations at ovulation –generation of action potentials in nerve fibers –uterine contractions during childbirth Each of these examples terminate naturally (self limiting) Homeostasis is achieved by negative feedback loops: the integrator detects deviations from set point and orchestrates responses produced by effectors that return the parameter toward the set point.

13. Explain “chills” at onset of a fever Explain “sweat” when a fever “breaks” How does Tylenol reduce a fever? To reach new, Higher set point If setpoint is suddenly reset to a higher temperature, then actual temperature is LESS THAN the new set point, so one feels “cold” and adds clothing, curls up, and shivers. These are “Chills.” If setpoint is reset to a lower temperature or back to normal, then actual temperature is GREATER THAN the new lower set point, so one feels “hot” and removes clothing, fans, and sweats. These are “the sweats” when a fever breaks. Central & Peripheral Thermoreceptors Tylenol and other non- steroidal anti- inflammatory drugs (NSAIDS) suppress the production of eicosanoids (IL-1, IL-6, etc) so effect of these on the set point in hypothalamus is minimized. p. 579 Fig 16-18

14. Plasma Glucose Homeostasis Glucose metabolism Hormonal Control Disruptions of glucose homeostasis A Case Study

15. Homeostasis of Plasma Glucose Concentration Normal physiological range: 65-100 mg/dl What is the set point? Why is too much plasma glucose harmful? Plasma glucose concentration = glucose entering the plasma – glucose leaving the plasma What are the mechanisms that regulate plasma glucose concentration? What are the components of the negative feedback loop: –Glucose receptors? –Afferent pathway? –Integrator? –Efferent pathway(s)? –Effector organ(s)? Phases: absorptive, post-absorptive, and fasting

16. Graph your daily caloric intake over a 48 hour period 6am 6pm Noon MN Calories consumed 6am Noon Plasma Glucose ? ? Overlay absorptive and post-absorptive phases on the graph

17. Fig. 16.01 =sink Absorptive Phase Hepatic Portal System Lipoprotein Lipase Once inside, glucose is converted to something else, thereby maintaining a concentration gradient for facilitated diffusion of glucose into cells.