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1、Chapter 6 Hypoxia,绝食,14天,绝水,7天,绝O2,数分钟,O2是人体的第一生命物质。,摄取,携带,运输,利用,Concept,Hypoxia can be defined as deficiency in either the delivery or the utilization of oxygen at the tissue level, which can lead to changes in function, metabolism and even structure of the body.,或,机能、代谢、形态结构异常,Parameters of blood
2、oxygen,1. partial pressure of oxygen, PO2,物理溶解于血浆中的氧所产生的张力,PO2 is the tension produced by oxygen molecules physically dissolved in plasma.,Partial pressure of inspired oxygen （吸入气氧分压， PiO2 ） Partial pressure of oxygen in the alveoli (肺泡内氧分压，PAO2 ),Acting factor,PaO2： 100 mmHg （ 13.3kPa ） PvO2： 40 mm
3、Hg （ 5.3kPa ）,Normal value,2. oxygen binding capacity, CO2max,100ml血液中Hb所能结合氧的最大毫升数,Maximal amount of oxygen that can be potentially bound by the haemoglobin is called oxygen binding capacity of haemoglobin.,Hb concentration and quality,Acting factor,Normal value : 20 ml%,100ml血液实际所含的氧量,3. oxygen co
4、ntent, CO2,The total oxygen content of blood includes oxygen that is bound to haemoglobin an physically dissolved in plasma.,PaO2； CO2 max,In artery:19ml%； In vein:14ml%,Acting factor,Normal value,4. oxygen saturation, SO2,SO2 is the percentage of haemoglobin present as oxyhaemoglobin.,In artery ：93
5、95 In vein ：7075,Acting factor： PaO2,Normal value,5. arteriovenous blood oxygen difference , AVDO2,动脉血与静脉血氧含量之差,19ml/dl,14ml/dl,5ml/dl,Normal value：5ml%,utilization of oxygen in the tissue,Acting factor：,Section 1 Classification, Etiology & Pathogenesis, Hypotonic hypoxia（低张性缺氧）,各种原因使PaO2，以致血氧含量 ，组织
6、供氧不足而引起的缺氧。,Hypotonic hypoxia is characterized by the decrease of PaO2, also called hypoxic hypoxia.,Etiology,1.Decrase PO2 of inspired air：plateau,2.External respiratory dysfunction：COPD,3.Venous-to-arterial shunts：congenital heart disease,Characteristics of blood O2,PaO2,其他：血氧含量，血氧饱和度,紫绀 (cyanosis
7、),HHb5g时，皮肤粘膜呈青紫色的现象, Hemic hypoxia（血液性缺氧）,Hemic hypoxia refers to the altered affinity of HB for oxygen or decrease in amount of HB in the blood.,Etiology,1.贫血（anemia）:最常见的血液性缺氧,HbCO2 樱桃红色,HbFe3+OH 石板色,肠源性紫绀, Characteristics of blood O2, 氧容量,其他：氧含量,PaO2和氧饱和度正常, Circulatory hypoxia（循环性缺氧）,由于组织血流量,使组
8、织供氧量所引起的缺氧。,Circulatory hypoxia refers to inadequate blood flow leads to inadequate oxygenation of the tissues.,1.Tissue ischemia：shock, heart failure,2.Tissue congestion：venous embolism,Etiology, AVDO2,其他： PaO2,动脉血氧含量,氧饱和度正常, Characteristics of blood O2, Histogenous hypoxia (组织性缺氧),组织细胞利用氧的能力下降所致的缺
9、氧，即氧利用障碍（dysoxidative hypoxia）,Histogenous hypoxia refers to the tissue cell cannot make use of the O2 supplied to them.,1.Inhibition of mitochondrial oxidative phosphorylation: cyanide(氰化物 ),2.Mitochondria injury: radiation, free radical,Etiology, AVDO2 ,其他：PaO2,A血氧含量,A血氧饱和度正常 PvO2、V血氧含量、V血氧饱和度, Ch
10、aracteristics of blood O2,Section 2 Functional and Metabolic Changes of the Body in Hypoxia,颈A体和主A体化学感受器,.Alterations of respiratory system,轻度缺氧 (3060mmHg),呼吸抑制,. Alterations of circulatory system,轻度缺氧,2.全身血流重新分布,保证心、脑血液供应,增加细胞供氧量,1.RBC增多,. Alterations of hematologic system,2.氧离曲线右移,2.重度缺氧或缺氧中、晚期： 氧
11、供不足使中枢神经系统功能异常。,1.轻度缺氧或缺氧早期： 血流重新分布保证脑的血流供应。,. Alterations of central nerve system,. Alterations of tissues and cells,（一）代偿性反应,1.细胞利用氧能力增强,慢性缺氧,2.无氧酵解增强,3.肌红蛋白（myoglobin）增加,肌红蛋白与氧亲和力较大，具有储存氧的作用。,有利于细胞在缺氧环境下生存。,4.低代谢状态,（二）细胞损伤,1.细胞膜的变化,(1)Na+内流,(2)K+外流,(3)Ca2+内流,Ca2+内流,2.线粒体的变化,3.溶酶体的变化,Section 3 Factors Involved in Tolerance to Hypoxia,1.代谢耗氧率,2.机体的代偿能力,个体差异显著,Section 4 Oxygen Treatment and Oxygen Intoxication,氧疗,1.提高PaO2,2.增加物理溶解的O2量,动-静脉氧差：5ml/100ml血,氧中毒 （oxygen intoxication）,3.分类：脑型氧中毒、肺型氧中毒,1.细胞受损机制与活性氧作用有关,2.发生取决于吸入气的氧分压而不是氧浓度,
