chap5-缺氧.ppt

北京大学医学部病理生理学教研室
赵亚莉
缺氧
Hypoxia
Clinical Example
In 1875 three French scientists ascended in a balloon. A height of over 26,000 feet (Bar. 280 mmHg) was reached. They lost consciousness at about 25,000 feet. When Tissandier regained consciousness the balloon was falling rapidly, but his panions were dead. Oxygen containers were carried in this ascent but Tissandier records that his arms became powerless and so he was unable to raise the mouthpiece to his lips. Why?
第一节概述
General Introduction
氧气的获得和利用:
ventilation
gas exchange
internal respiration
external respiration
air
alveoli
Alveolar
capillary
Gas
transport
Tissue
cells
运送氧或利用氧发生障碍时,机体发生功能、代谢、形态结构改变的病理过程.
hypoxia的概念
血氧指标
一、血氧分压
(Partial Pressure of Oxygen, PO2)
影响因素:
吸入气体氧分压
外呼吸的功能
定义:溶解于血液中的氧所产生的张力。
PaO2 100mmHg
影响因素:
Hb的质和量
定义:100 ml血液中Hb被氧充分饱和时的最大带氧量。
=20ml/dl
三、血氧容量
(Oxygen Capacity)
体外标准条件( PO2为150 mmHg、二氧化碳分压为40 mmHg,温度为380C)下测定
定义:体内100ml血液的实际带氧量。
溶解氧()+结合氧
A: 19ml/dl V:14ml/dl
Hb的质和量;PaO2
影响因素:
二、血氧含量
(Oxygen Content)
动静脉血氧差
19ml/dl
14ml/dl
5ml/dl
O2
O2
O2
O2
O2
A
V
定义:动脉血氧含量- 静脉血氧含量,反映组织对氧的摄取和利用能力.