How do the kidneys and lungs act in acid-base balance?

Question

How do the kidneys and lungs act in acid-base balance? Define respiratory acidosis/alkalosis and metabolic acidosis/alkalosis. What are their causes?

Answer 1

Acidosis is when the pH of blood falls below the norm (7.4 pH) and alkalosis is when the pH of blood rises above the norm.

The kidney's role is to remove nitrogenous wastes from the blood while conserving the proteins and water. Removal of nitrogenous wastes keeps the blood pH levels more in the normal range.

One of the by products of cellurlar respiration (this is where glucose is broken down to CO2 and water with a release of energy which is used to construct ATP, the energy "currency" needed for cellurlar metabolism. The CO2 is transported back to the lungs via the plasm of the blood. Since blood plasma is mainly water, the water mixes with the CO2 to form a week acid. The when the blood is transported to the lungs, the CO2 is exchanged for oxygen, via diffusion in the alveole of the lungs. This reduces the "acidity" of the blood.. Hyperventalation, when you take deep breaths but exhale shallowly, increases acidity in the blood because you do not exhale enough of the CO2, thus the blood pH decreases resulting in acidosis. Emergeny rooms treat hyperventalation by having an individual "breathe" into a paper sack. Really high teck, huh! This causes the individual to "think" about his breathing by making him exhale more deeply to "blow up" the sack. Thus, the carbon dioxide in his blood is reduced, reducing the acidity.

An interesting side note: Different animals have different levels of water in their urine. Desert animals excrete a urine that is almost solid. This is because their kidneys conserve most of the water during the process of filtering the blood because water is a limited commodity in dessert animals. Have you noticed that you urinate more in winter than summer? Your body responds very much like the dessert rat in summer . . . because you lose more water due to perspiration in the summer than you do in the winter your body tends to conserve more of the water in your urine, thus making your urine more concentrated. In the winter, your urine is quite dilute. Homeostatic control of water levels via the kidneys is a grand contributor to pH levels in the blood.

ANATOMY AND PHYSIOLOGY TEACHER

Answer 2

1

Answer 3

The lungs can affect blood acid/base balance by blowing off CO2 or letting the level of CO2 rise. Increases in CO2 increase the acidity of the blood and therefore decrease pH. This is an immediate and short lived method of controlling pH. The kidney on the other hand takes hours to work but can adjust the pH by controlling the amount of acid excreted, also the buffering agents. Respiratory acidosis is when there is a build up of CO2 causing a decrease in pH. Respiratory alkalosis is the opposite, a decrease in CO2 caused by hyperventilation which raises the pH. Metabolic acidosis and alkalosis can be caused by an imbalance in the way the kidneys are working or by ingestion of acids or bases.

Answer 4

They are two in number - so can be transplanted from one human to the other if required. And a man can survive on one. They are the filteration plant of our body, which pulls out all the waste products (Liquid) and helps keep our body clear of toxins.