FEEDBACK MECHANISMS TEMPERATURE REGULATION AND OSMOTIC BALANCE

Homeostasis

• Animals in the Serengeti are moving towards greener land to survive.

  • Wildebeests conserve energy by moving mechanically.

  • They mobilize energy stored in fat deposits when there is no food.

  • Body systems work together for survival during the journey.

• Homeostasis is crucial for maintaining a stable internal state in animals.

  • Organs and systems adjust to internal and external changes.

  • Negative feedback relationships help in stabilizing conditions.

  • Homeostasis aims to maintain equilibrium around a specific set point.

• Stimulus, receptor, and response are key elements in the body's adjustment to changes.

Negative Feedback

• Negative feedback loop changes the stimulus direction to maintain balance.

  • Example: Regulation of blood glucose levels through insulin and glucagon.

• Positive feedback loop maintains the stimulus direction, possibly accelerating it.

  • Examples: Blood clotting and uterine contractions during childbirth.

• Thermoregulation controls body temperature in animals.

  • Ectotherms rely on external temperatures, while endotherms maintain a constant body temperature.

  • The hypothalamus in the brain plays a vital role in temperature control.

Thermoregulation

• Thermoregulation is essential for animals to adapt to environmental temperature changes.

• Different types of animals based on temperature regulation: ectotherms, poikilotherms, homeotherms, and endotherms.

• The hypothalamus responds to chemicals in the body to regulate temperature.

• Fever is a defense mechanism triggered by the body to fight infections.

Osmotic Balance

• Osmosis and osmoregulation are crucial for maintaining salt and water balance in the body.

• Electrolytes and non-electrolytes contribute to osmotic balance.

• Body fluids include blood plasma, cytosol, and interstitial fluid.

• Semi-permeable membranes allow the passage of certain solutes and water.

• Regulation of osmotic pressure is vital to prevent the accumulation of toxic waste and water in the body.

• Dehydration from Drinking Sea Water

  • Human body cannot adapt to drinking sea water due to its hypertonic nature compared to body fluids.

  • Organisms like goldfish, known as euryhaline organisms, can tolerate a wide range of salinity.

  • Some fish have evolved osmoregulatory mechanisms to survive in various aquatic environments.

• Osmoregulation in Fish

  • Fish are osmoregulators and use different mechanisms to survive in freshwater and saltwater environments.

  • Salmon physiology responds differently in freshwater and seawater to maintain osmotic balance.

• Homeostasis

  • Homeostasis is when the human body maintains a steady state through cells, tissues, organs, and organ systems.

  • Various variables within narrow ranges are kept compatible with life.

• Response to Environmental Changes

  • Changes in the internal or external environment are stimuli detected by receptors.

  • The system responds by adjusting activities to move values back towards the set point.