动物生理学5.呼吸系统生理(上) PPT课件

Pleura ： surrounding each lung is a serous (含浆液的） membrane, the pleura. The out layer adheres to the inner thoracic wall and the diaphragm. The inner layer covers the lung the potential space between the two layers is called the pleural cavity, the layers normally move easily over each other with movement of the thorax. Pressure in the interpleural space is always negative.（平静呼吸时） 气胸（P呼吸暂停时 胸膜腔内压＝大气压－肺回缩压 若以大气压为“0” 胸膜腔内压＝－肺回缩压
Intrapulmonary pressures 肺内压 平静呼吸 吸气时 -2~ -1 mmHg (-0.266~ -0.133Kpa) 呼气时 1~ 2 mmHg (0.133~ 0.266Kpa) 用力呼吸 (forced breathing) 用力吸气 -100~ -30 mmHg 用力呼气 60~ 140 mmHg
5 Respiration
Chemical reduction of molecular oxygen to form water is the primary source of energy for animals. The principal site for the reaction occurs within the mitochondria. Without this reaction life cannot exist for more than seconds. Coincidental with the reduction of O2 is the production of CO2; this comes mainly from oxidative phosphorylation of glucose which also occurs principally in the mitochondrion. Repiration includes: The gases must be moved between the environment and the lungs, usually referred to as “pulmonary ventilation” The gases must be exchanged between the spaces in lung and the blood Exchange of gases between the blood and the various tissues must occur Finally transfer of gases must occur within the tissue to sites of utilization (for O2 ) and from the sites of production (for CO2)
The pressure in thoracic cavity (intrapleural pressures)
胸膜腔内压
• pulmonary ventilation: As long as interplueral pressure remains less than atmospheric pressure, the dimensions of the lungs follow closely the dimensions of the thoracic cavity. Lung movements results from contraction of respiratory muscles associated with the movement of structures in thoracic cavity wall and of the diaphragm.
5.1 pulmonary ventilation
Gas exchange between the environment and the lungs, usually referred to as “pulmonary ventilation” The structures needed for pulmonary ventilation: airway, alveoli [æl’viəlai] (单数 alveolus ), and thorax
胸腔负压也可作用于腔静脉和胸导管，影响静脉 血和淋巴的回流。
5.1.1.2 肺通气的阻力 肺通气的阻力有两种： 弹性阻力（70%），包括肺的弹性阻力和胸廓的弹性阻力 非弹性阻力（30%），包括气道阻力等 弹性阻力和顺应性（Compliance） C＝V/P (L/cmH2O) 肺表面活性物质（pulmonary surfactant) 是复杂的脂蛋白混合物，主要成分是二软脂酰卵磷脂 （DPPC）和表面活性物质结合蛋白（SP）。作用是降低肺 泡液－气界面的表面张力，而肺的回缩力减小。 生理意义：维持肺泡的稳定性；减少肺间质和肺泡内组织 液生成，防止肺水肿；降低吸气阻力，减少呼吸做功。 早产婴儿
5.1.1
肺通气的原理
5.1.1.1 肺通气的动力 直接动力 肺泡与外界环境之间的压力差 原动力 节律性呼吸运动 Respiratory movements (呼吸运动） Respiratory muscle: diaphragm(膈), intercostal muscle, et al Thoracic cavity Inspiratory movement & Expiratory movement 呼吸运动的形式： 腹式呼吸和胸式呼吸 平静呼吸和用力呼吸