1 / 12

Homeostasis

Explore the concept of homeostasis and how it regulates and maintains internal conditions within an acceptable range. Learn about negative and positive feedback loops and their role in maintaining homeostasis. Discover examples of thermoregulation, osmoregulation, gas exchange, blood glucose regulation, and more.

arnoldh
Download Presentation

Homeostasis

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. Homeostasis

  2. What is homeostasis? (same) (state) • Regulation and internal maintenance of the body • The body works best when internal conditions are within an acceptable range; homeostasis helps to do this

  3. Feedback Loops • Homeostasis controls internal conditions with feedback loops • NEGATIVE feedback loop – the product inhibits the process that creates them • Ex: control of body temperature, thermostat • Common homeostatic mechanism • POSITIVE feedback loop – the product amplifies the process that creates them • Ex: labor, global warming

  4. Feedback Loop NEGATIVE POSITIVE

  5. Homeostasis Examples • Thermoregulation (temperature) • Osmoregulation (water) • Gas Exchange • Blood Glucose • Guard Cells • Other examples: • pH • Blood pressure • Hormone levels • Metabolism

  6. ThermoregulationORGAN IN CHARGE  BRAIN • Hypothalamus scans temperature of blood as it passes through • Too high  blood vessels dilate, sweating occurs • Too low  blood vessels constrict, shivering

  7. FRESHWATER SALTWATER Osmoregulation • Regulation of the balance of water and solutes (salt, ions) in the body • Aquatic Organisms: • (Freshwater) Protists – don’t forget about the contractile vacuole! • Freshwater fish – environment is hypotonic to the fish; fish take in lots of water • Solution  fish excrete LOTS of very dilute urine to conserve solutes • Saltwater fish – environment is hypertonic to the fish; fish loses water to osmosis • Solution  fish have specialized gills to excrete excess ions

  8. OsmoregulationORGAN IN CHARGE  BRAIN/KIDNEYS • Terrestrial Animals • Water is constantly being lost through evaporation, perspiration, urination • Water lost through these avenues needs to be replaced by drinking and eating • Concentration of urine allows solutes to be excreted while conserving water (kidneys)

  9. Osmoregulation – Land Animals

  10. Guard Cells (Plants) ORGAN IN CHARGE  LEAF • Leaves take in CO2, release O2 and H2O through stomata • Guard cells surround the stomata • Water abundant  water pressure HIGH, stomata OPEN, release water, CO2 enters • Water scarce  water pressure LOW, stomata CLOSED, loss of water limited • Generally  • Stomata open during the day (photosynthesis) • Stomata closed during the night (decreased photosynthesis, prevent water loss) • Exceptions  HOT DRY conditions may result in closed stomata during the day

  11. Gas Exchange in MammalsORGAN IN CHARGE  LUNGS • Oxygen-rich air (poor in CO2) is taken in during inhalation; moves to alveoli • Oxygen-poor blood (rich in CO2) vessels surround the alveoli • Passive transport moves the oxygen from alveoli into the blood, CO2 from blood into the alveoli • Oxygen delivered to cells through the blood vessels; CO2 expelled during exhalation

  12. Regulation of Blood Glucose ORGAN IN CHARGE  PANCREAS • Blood sugar too high: • Pancreas releases insulin; body cells take in glucose and moves it to long term storage in liver (glycogen) • Blood sugar too low: • Pancreas releases glucagon; stimulates liver to break down stored glycogen (into glucose) and release into bloodstream

More Related