Environment: Homeostasis

Environment: Homeostasis

Homeostasis is a complex and vital process that maintains a constant internal environment despite changes in the external environment. For an organism to function properly, it’s crucial that its physiological and biochemical parameters remain fairly constant.

Basics of Homeostasis

  • Homeostasis refers to the ability of an organism or cell to maintain equilibrium by adjusting its physiological processes.

  • Key mechanisms of homeostasis include regulation of body temperature, water balance, blood sugar levels, blood salt levels, and blood pressure.

  • The nervous system and the endocrine system play significant roles to achieve homeostasis.

Homeostasis in Action: Body Temperature

  • The thermoregulatory centre in the brain, particularly in the hypothalamus, regulates body temperature around a typical set point of 37°C.

  • When the body temperature rises, the thermoregulatory centre triggers responses like sweating and vasodilation (widening of blood vessels) to lose heat.

  • If the body temperature falls, responses like vasoconstriction (narrowing of blood vessels), shivering and increased metabolic rate help to conserve and generate heat.

Homeostasis in Action: Water Balance

  • Osmoregulation maintains the balance of water and electrolytes in the body.

  • The kidneys play a crucial role in osmoregulation by filtering the blood and excreting excess water, helps maintain constant blood volume and pressure.

  • The hypothalamus detects changes in blood concentration and regulates the release of ADH (antidiuretic hormone).

  • Upon detection of high blood concentration, ADH, produced by the pituitary gland, stimulates the kidneys to reabsorb more water, resulting in concentrated, low volume urine.

Homeostasis in Action: Blood Sugar Levels

  • The process of maintaining the right level of blood glucose is known as glucose homeostasis.

  • An increase in blood glucose triggers the release of insulin from the pancreas, stimulating cells to take up glucose, thus lowering blood glucose levels.

  • A decrease in blood glucose triggers the release of glucagon, also from the pancreas, prompting the liver to release glucose back into the bloodstream.

In revising the concept of homeostasis, ensure you not only understand the definition of the term, but also the specific examples provided above. Being able to describe the feedback mechanisms that enable the body to respond to changes and maintain a stable environment is crucial.