How the Body Regulates pH
There are three important mechanisms the body uses to regulate PH. The first is a chemical buffer, the second line of defense is the respiratory system, and last, is the urinary system. These three mechanisms work together to keep body pH within that narrow range.
The most important chemical buffer is Bicarbonate (HCO3). The body uses bicarbonate to perform a chemical reaction with strong acids and bases on a regular basis. For reference, look at the simplified equation below.
The H ion binds to the hydrogen, leaving the reaction with water and CO2, which can easily be eliminated by breathing and urination. This reaction can also be reversed, if more H+ ions are needed to be released into the blood and make it more acidic. The kidneys aid in this process by releasing Bicarbonate when it is needed.
HCO3 + H = H20 + CO2
Another vital component to acid base balance is respiration. Our lungs regulate how much CO2 is in our blood. This is important because it can reverse the above reaction and combine with water to form bicarbonate. If a person were to breathe in and out at a rapid rate or hyperventilate, this would decrease the amount of CO2 in the blood, thus reducing the amount of Bicarbonate.
With less Bicarbonate, there will be less H+ ions in the blood, and pH will rise. However, this is a short fix for pH balance.
The kidneys are the third and final component to acid base balance in the body. They can absorb more acids or bases as needed to keep the body at homeostasis or normal. Since our bodies tend to produce more acids, and we tend to have more acidic diets, urine is slightly acidic to get rid of some of it. Recall that the kidneys can also produce more bicarbonate when needed.
The titration screen experiment has been designed to be a free flexible tool for teachers and students. You can choose to carry out a strong acid - strong base titration (or any combination of strong and weak acid-base titrations). There is also a redox titration experiment to complete in order for students to practise their understanding and skills.
This resource meets the needs of many specifications for students of ages 14-18 years.
This resource allows students to run their own titration experiment on a computer or tablet before taking part in the real thing. The advantages to this approach are that the students will become more confident and familiar with the procedures in the laboratory. They may also feel less rushed and better understand the reason for each task. After using this resource feedback suggests there is more time in class to focus on practical skills and developing understanding.
The Royal Society of Chemistry would like to thank Dr Simon Rees (Chemistry Teaching Fellow, The Foundation Centre, Durham University) for his help and advice during the development of this resource.