文档介绍：第二节肺换气和组织换气
Pulmonary Ventilation and
Tissues Ventilation
一、气体交换的原理 principle of gas exchange
(一)气体扩散 gas diffusion
气体分子不停的进行着无定向的运动,其结果是气体分子从分压高处向分压低处发生净转移,这一过程称为气体扩散。
Gas molecules move freely among one another. The result is gas molecules diffuse from high-pressure area toward low-pressure area. The process is called gas diffusion.
肺换气和组织换气就是物理性的扩散过程。
Pulmonary ventilation and tissues ventilation are physical diffusion processes .
气体扩散遵循着以下物理原则 gas diffusion obeys the following physical principles
。
Gas diffuses from the high-pressure area to the low-pressure area.
,决定于该气体的分压差、气体的扩散速度和气体在液体中的溶解度。
The diffusion direction and volume of gas is decided by its own partial pressure difference、diffusion rate and the solubility in fluid.
-液交界面,气体的扩散速度与它在液体中的溶解度密切相关。溶解度高的扩散快。
In the fluid or at the interface of gas and fluid, the diffusion rate of gas is correlate closely to its solubility in fluid. The gas which solubility is higher diffuses quicker.
∝(1/ √气体分子量)。分子量大的扩散速度慢。
Diffusion rate of gas ∝(1/ √molecular weight)The gas which molecular weigh is larger diffuses slowlier.
单位时间内气体扩散的容积为气体扩散速率,它受下列因素影响
The volume of gas diffusion in unit time is called diffusion rate. It is effected by the following factors
分压差×扩散面积×温度×气体溶解度
扩散距离×√分子量
扩散速率
∝
D∝
△P*T*A*S
d*√MW
:分压差大--扩散快
Gas partial pressure difference: gas partial pressure difference is larger—diffuses faster
:溶解度高,扩散快
分子量大,扩散慢
Gas molecular weight and solubility:
when solubility is high, it diffuses fast
when molecular weight is large,it diffuses slowly.
3. 肺泡膜的扩散面积:扩散面积大,扩散快
Diffusion area of alveolar membrane : when diffusion area of alveolar membrane is large,it diffuses fast.
安静状态下,肺泡扩散面积40m2
diffusion area of alveolar membrane is 40m2 in normal quiet state.
运动时肺泡扩散面积70m2
diffusion area of alveolar membrane is 70m2 during sports.
疾病状态时下降
diffusion area of alveolar membrane decreases in disease.
4. 扩散距离-肺泡