Explain how the body of an animal defends itself by against changes in H+ion concentration
The body of an animal maintains its acid-base balance through various mechanisms to defend itself against changes in H+ (hydrogen ion) concentration, which determines the acidity or alkalinity of a solution.
The primary way the body defends itself against changes in H+ ion concentration is by regulating the levels of carbon dioxide (CO2) and bicarbonate ions (HCO3-) in the blood. Carbon dioxide is a waste product of cellular respiration, and it is carried in the blood in the form of bicarbonate ions.
When the H+ ion concentration in the blood increases (making the blood more acidic), the body responds by increasing the elimination of carbon dioxide. This can occur through increased respiratory rate or depth, as more CO2 is exhaled. Removing CO2 from the body reduces the H+ ion concentration, helping to restore the acid-base balance.
Conversely, when the H+ ion concentration in the blood decreases (making the blood more alkaline), the body can decrease the elimination of carbon dioxide. This reduces the loss of H+ ions, helping to increase the acid-base balance.
Additionally, the kidneys play a vital role in regulating H+ ion concentration in the body. They help maintain a balanced pH by selectively reabsorbing or excreting hydrogen ions and bicarbonate ions in the urine. When the body needs to increase the H+ ion concentration, the kidneys excrete more H+ ions and reabsorb more bicarbonate ions. Conversely, when the body needs to decrease the H+ ion concentration, the kidneys excrete more bicarbonate ions and reabsorb more H+ ions.
Furthermore, buffer systems in the body, such as the bicarbonate buffer system, help minimize changes in H+ ion concentration. Buffer systems consist of a weak acid and its conjugate base, and they act to resist changes in pH by accepting or donating H+ ions as needed. In the bicarbonate buffer system, bicarbonate ions can act as a base by accepting H+ ions to decrease acidity or as an acid by donating H+ ions to decrease alkalinity.
Overall, the body's defense against changes in H+ ion concentration involves respiratory adjustments, renal regulation, and buffer systems, all working together to maintain the acid-base balance and ensure proper functioning of cells and tissues.