BUFFERS

1. BUFFERS TEST YOUR SALIVA http://www.youtube.com/watch?v=D-ybSUw6jCM

2. Body pH refers to the pH of the fluids inside and outside of the cells. The pH of almost all living systems is between pH _____________. Maintaining the proper pH then is vital living systems. Since we are mostly made of water, the pH level effects all body chemistry, health and disease. Extended pH imbalances of any kind are not well tolerated by the body. All regulatory mechanisms (including breathing, circulation, digestion, hormonal production, etc.) help to balance pHby removing acids from the body. 6 - 8

3. If the pH becomes too acidic or too basic, cells become poisoned by their own toxic waste and die. Just as acid rain can destroy a forest, an imbalanced pH continuously corrodes all body tissue, slowly eating into our veins and arteries. If left unchecked, an imbalanced pH will interrupt all cellular activities and functions, from the beating of your heart to the neural firing of your brain. Although it may generally go unnoticed and undetected for years, an imbalanced pH can lead to the progression of most, if not all, degenerative diseases.

4. How can it do this? Heart Disease: An acidic pH erodes and eats into cells of the heart, arteries and veins, weakening their structures. This causes microscopic tearing and can add to the heart's workload and may eventually lead to high blood pressure and heart attack. Cancer:cancerous cells grow well in acidic environments, therefore an acidic pH will accelerate and increase the possibility of cancer. Weight Gain: If you have an acidic pH for an extended period of time, this can trigger insulin sensitivity. This causes more insulin to be released and the body will convert every calorie it can into fat. Diabetes: Acidic pH is thought to be a precursor to diabetes mellitus. With increased pressure to continually produce insulin, cells in the pancreas simply burn out and die. When the amount of insulin released by the pancreas decreases and eventually stops, you have diabetes (and can no longer store the sugars you eat – you pee them all out).

5. In humans, a blood pH of 7.46 (slightly basic) is considered optimal. Many other tissues that deal with the external environment (colon, living skin, vagina, stomach, lymph node fluid), rely on an acidic pH for their proper function. The body has several fail-safe mechanisms to regulate the blood pH and keep it suitable for life, primarily through … BUFFERS

6. If we add a strong acid to water, the pH will change dramatically. Example: if you add a strong acid such as HCl to water, it will release a hydrogen ion into the water. H2O + HCl → H2O + H+ + Cl-. The resulting large concentration of (H+) makes the solution more acidic and leads to a dramatic drop in the pH. More H+ ions

7. If you add a strong base such as NaOH to water, the ions float apart leading to extra OH- ions in the water: H2O + NaOH → H2O + Na+ + OH- The resulting large concentration of OH- makes the solution more basic and leads to a dramatic increase in the pH. Less H+ ions

8. Abufferis… • A chemical thatcan resist changes in pHby: • When it is in aBASICsolution, a buffer willrelease H+ ions into the solution • 2. When it is in anACIDICsolution, a buffer willabsorb H+ ions into the solution Therefore, if we want to add a strong acid or base to a solution without causing a large change in the pH, we need to create a buffer solution. See p.16-18 Fluids & Electrolytes CD

9. In a strong acid solution, there are too many hydrogen ions. So, if we add a strong acid to a solution with a buffer, the buffer is attracted to the hydrogen ions. So the NEGATIVE buffer (example: CO32-) will react with the H+ to form (in this case) HCO3-. H+ + CO32-HCO31- Therefore, the H+ gets absorbed by the buffer and the pH of the solution does not change. When it is in an ACIDIC solution, a buffer will absorb H+ ions.

10. In a strong base solution, there are too many hydroxide ions. So if we add a strong base to a solution with a buffer, the buffer (example: H2CO3) will give up its H+ in order to transform the base (OH-) into water (H2O), also written as H(OH). Because the buffer has lost a H+, it will become HCO31-. OH- + H2CO3 H(OH) + HCO31- Therefore, the OH- gets turned into water and the pH of the solution does not change. When it is in an BASIC solution, a buffer will donate/release H+ ions.

11. A buffer usually has 3 (or more) ‘versions’ of itself. In the case we just looked at, the buffer could either be: H2CO3 HCO31- CO32- In Basic Solution In Acidic Solution

12. can be OVERLOADED A buffer ______________________ in a high acid or base concentration, because eventually you ___________________________ available. use up all of the buffers that are See p.18 Fluids & Electrolytes CD

14. BUFFER ANIMATIONS http://www.greenandwhite.net/~tfchan/Animations/flash-animations/buffer12.swf (turn off the sound)

15. donate In conclusion, a buffer can either ___________ or ___________ H+ as needed. accept The most important buffer in our bodies is the __________________, which is found in the blood. bicarbonate ion

16. SEE BLACKBOARD FOR THE “WHOLE PICTURE”!!