1 / 19

Human Physiology 9-1-11

Sweating is a vital physiological process regulated by the hypothalamus, primarily through the sympathetic nervous system (SNS). The SNS releases acetylcholine onto sweat glands, enhancing sodium (Na+), chloride (Cl-), and water transport to the skin surface. This process effectively dissipates heat, especially in high humidity. Body temperature regulation is critical, with sensors triggering responses to maintain homeostasis through mechanisms like sweating and shivering. Disturbances like hypothermia and hyperthermia illustrate the body's response to extreme temperature changes, emphasizing the importance of maintaining a stable internal environment.

isaac-cox
Télécharger la présentation

Human Physiology 9-1-11

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Human Physiology 9-1-11

  2. SweatingHypothalamus --> SNS output-->SNS releases acetylcholine (ACH) on sweat glands--> stimulates Na+ active (with ATP) transport out of sweat gland--> Cl- follows passively--> water follows movement of ions Skin surface Na, Cl, water SNS nerve Sweat gland

  3. Sweating continued….In profuse, long-term sweating:As the Na+, Cl- and water continue up the duct toward the skin surface, K+ exchanged for Na+,HCO3- exchanged for Cl- with expenditure of ATP.

  4. Sweating, continued….When the ionic mixture reaches the skin surface, water is evaporated, leaving the ions on the skin. Water Na+, Cl-, K+, HCO3-

  5. Sweating is a highly effective way (600 kcal/L) of losing heat A given amount of sweat causes much more heat loss than it cost to produce it.The effectiveness of sweat varies with relative humidity

  6. Regulation of body temperatureBody temperature is the only homeostatically regulated variable that is not allowed to change before the regulator takes action.The regulator takes action in response to a potential change in body temperature, not an actual one.

  7. Tb --> sensors--> hypothalamus --> SNS --> sweating ( heat loss) vasodilation ( heat loss)----> TbTb --> sensors--> hypothalamus--> motor --> shivering ( heat prod.) SNS -- >vasoconstriction and piloerection ( heat loss) ----> Tb

  8. Metab. rate Air Temperature

  9. HypothermiaIf heat loss > heat production, Tb If negative feedback cannot bring Tb , then positive feedback can occurTb  --> heat production  --> Tb  --> heat production  --> Tb , etc. Log Metabolic rate Body temperature

  10. Hypothermia98 --> 95 F extreme shivering, change in mental ability, lack of coordination, slurred speech, aggression94 F---> greatly impaired mental and physicalbelow 85 F lose ability to shiverbelow 78 F heart stops

  11. FrostbiteTo protect the core body temperature, the brain may shunt warm blood away from the areas with highest heat loss (fingers,toes, nose, ears) to the core.As area cools, skin red--> skin white--> pain--> numb--> freeze--> cells killed

  12. HyperthermiaA. fever--a regulated rise in Tb“Pyrogens” are small proteins released by white blood cells that detect pathogens. Pyrogens then cause the production of a fever

  13. Fever New set point Tb Time

  14. Benefits of fever1. White blood cells more mobile at higher Tb2. WBC’s more able to kill pathogen at higher body temperature3. Some pathogens killed directly by higher TbAntipyrogens (aspirin, acetominophen) decrease set point.

  15. 2. Exercise induced hyperthermia (also a regulated rise in body temperature)

  16. HyperthermiaC. heat stroke (unregulated rise in body temp) If heat loss < heat production + heat gain from environment, Tb If negative feedback cannot bring Tb , then positive feedback can occurTb  --> heat production  --> Tb  --> heat production  --> Tb , etc. Log metab. rate Body temp.

More Related