浙江大学医学院：酸碱平衡（PPT讲稿）Acid-Base Balance

Acid-Base Balance Jianzhong Sheng MD, phD Department of Pathophysiology School of medicine Zhejiang University

Acid-Base Balance Jianzhong Sheng MD, PhD Department of Pathophysiology School of Medicine Zhejiang University

Objectives Explain how the ph of the blood is stabilized by bicarb buffer and define the terms acidosis and alkalosis Explain how the acid-base balance of the blood is affected by co, and Hco and describe the roles of the lungs and kidneys in maintaining acid-base balance Explain how CO, affects blood pH, and hypoventilation and hyperventilation affect acid-base balance Explain how the interaction between plasma K+ and h concentrations affects the tubular secretion of these

Objectives ◼ Explain how the pH of the blood is stabilized by bicarb buffer and define the terms acidosis and alkalosis. ◼ Explain how the acid-base balance of the blood is affected by CO2 and HCO3 - , and describe the roles of the lungs and kidneys in maintaining acid-base balance. ◼ Explain how CO2 affects blood pH, and hypoventilation and hyperventilation affect acid-base balance. ◼ Explain how the interaction between plasma K+ and H+ concentrations affects the tubular secretion of these

Normal acid Base balance Normal pH 7 35-7.45 Narrow normal range Compatible with life 6.8-8.0 pH 6.8 735 745 7,8 death acidosis alkalosis death H+】160 40 16 nmol/L

Normal Acid-Base Balance ◼ Normal pH 7.35-7.45 ◼ Narrow normal range ◼ Compatible with life 6.8 - 8.0 7.35 7.45 acidosis 6.8 alkalosis 7.8 death death pH 【H 160 40 16 nmol/L +】

What are acidosis and alkalosis a Normal ph:7.40(7.35-7.45) Acidosis: pH7.45 Simple types of acidosis: Metabolic acidosis and respiratory acidosis Simple types of alkalosis: Metabolic alkalosis and respiratory alkalosis Mixed types of acid-base disorders

What are acidosis and alkalosis ◼ Normal pH: 7.40 (7.35-7.45) ◼ Acidosis: pH7.45 ◼ Simple types of acidosis: Metabolic acidosis and Respiratory acidosis ◼ Simple types of alkalosis: Metabolic alkalosis and Respiratory alkalosis ◼ Mixed types of acid-base disorders

pH of blood is 7.35 to 7.45 pH=6.1+ log [ HCO3I 0. 03x Pco a[Hco3]/[H2Co3]=20:1

pH ◼ pH of blood is 7.35 to 7.45 ◼ pH = 6.1 + log [HCO3 - ] 0.03 x Pco2 ◼ [HCO- 3] / [H2CO3] = 20:1

Types of Acids in the body a volatile acids Can leave solution and enter the atmosphere. H2 CO3(carbonic acid ). Pco2 is most important factor in ph of body tissues

Types of Acids in the Body ◼ Volatile acids: ◼ Can leave solution and enter the atmosphere. ◼ H2CO3 (carbonic acid). ◼ Pco2 is most important factor in pH of body tissues

Types of Acids in the body Fixed acids Acids that do not leave solution Sulfuric and phosphoric acid. Catabolism of amino acids nucleic acids, and phospholipids

Types of Acids in the Body ◼ Fixed Acids: ◼ Acids that do not leave solution. ◼ Sulfuric and phosphoric acid. ◼ Catabolism of amino acids, nucleic acids, and phospholipids

Types of Acids in the body Organic Acids Byproducts of aerobic metabolism, during anaerobic metabolism any during starvation, diabetes. Lactic acid ketones

Types of Acids in the Body ◼ Organic Acids: ◼ Byproducts of aerobic metabolism, during anaerobic metabolism and during starvation, diabetes. ◼ Lactic acid, ketones

Chemical Buffers Act within fraction of a second a Protein HCO3. Phosphate

Chemical Buffers ◼ Act within fraction of a second. ◼ Protein. ◼ HCO3 - . ◼ Phosphate

Proteins coo or NH Largest pool of buffers in the body. pk, close to pH in plasma. Albumin, globulins such as Hb

Proteins ◼ COOH or NH2 . ◼ Largest pool of buffers in the body. ◼ pk. close to pH in plasma. ◼ Albumin, globulins such as Hb