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Announcements

Announcements. Personal info due today. Drop off on front table. Switch to Tuesday Morning Lab? Community of Scholars Research Symposium Saturday Sept 11 from 9- noon 10 weeks paid research on topic of your choosing! Summer 2011. 1QQ # 2. Name on top edge, back side of paper

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Announcements

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  1. Announcements • Personal info due today. Drop off on front table. • Switch to Tuesday Morning Lab? • Community of Scholars Research Symposium • Saturday Sept 11 from 9- noon • 10 weeks paid research on topic of your choosing! • Summer 2011

  2. 1QQ # 2 Name on top edge, back side of paper Answer on blank side of paper. Answer one of the following: • Suppose a person is exercising intensely. How would the pH of this person’s blood compare to the same individual at rest? Use the relevant chemical equation as part of your explanation. • Which body fluid compartment has the lowest concentration of proteins and why?

  3. A Taxonomy of Cognitive Skills for Developing Student Assignments and Assessments* *SC SDE (Pat Mohr). Adapted from Lorin W. Anderson, David R. Krathwohl et al (Eds.) A Taxonomy for Learning, Teaching, and Assessing: A Revision of Bloom’s Taxonomy of Educational Objectives 2001; modified by Ellen Goldey, Wofford College, to incorporate “Biology in Bloom,” Crowe et al., 2008, CBE – Life Sci Edu., 7: 368-381. **HOCS = higher order cognitive skills, LOCS = lower order cognitive skills.

  4. Cell Membrane: selectively permeable Capillaries: highly permeable except to proteins

  5. Thermoregulation An example of homeostasis bynegative feedback.

  6. Modes of Heat Exchange: Conduction Convection Radiation Evaporation ~37oC

  7. Modes of Heat Exchange: Conduction Convection Radiation Evaporation ~37oC

  8. http://www.nws.noaa.gov/os/windchill/windchillglossary.shtml

  9. Endotherms and Ectotherms Endotherms regulate core body temperature near a set point. Ectotherms do not achieve a constant body temperature; body temp approximates the temperature of the environment. Bears Advantages and disadvantages of each mode?

  10. Physics of thermal energy flow Cell metabolism=main source of heat Is cooling more effective if sweat is toweled away? Answers from Physics ProfessorDr. Salley

  11. Mechanisms of thermoregulationFor constant body temp heat gain = heat loss • Reflex arc • Negative feedback • Examples • Acclimatization vs. adaptation

  12. Types of Stimuli:MechanicalElectrical Chemical LightThermal

  13. Negative Feedback Loop Negative feedback Compares “actual” condition to “desired” condition (set point)

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

  15. Negative feedback loops: What to look for • The stimulus (temperature, etc.) • Sensors (thermo-, chemo-, photo-, mechano- receptors • Afferent pathways to integrator (may not exist) • Integrators (typically neurons or endocrine cells) • Efferent pathways from integrator • nerves • hormones • Effector cells or organs • virtually any cell • especially glands and muscles • The response (opposes stimulus)

  16. Thermoregulation in a comatose patient? In steady state: Heat gain = Heat loss What if room temperature was increased or decreased? What if additional covers were added to the patient?

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

  18. Central &PeripheralThermoreceptors p. 595 Fig 16-19 If setpoint is 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.” • Explain “chills” at onset of a fever • Explain “sweat” when a fever “breaks” • How does Tylenol reduce a fever? 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. 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. To reach new, Higher set point

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