BIO271H1 Lecture Notes - Lecture 7: Carbonic Anhydrase, Central Chemoreceptors, Aortic Body
Document Summary
All respiratory organs have to be thin and moist. Two major animal lineages have colonized terrestrial habitats: arthropods: crustaceans, chelicerates, insects, vertebrates: fish, amphibians, reptiles, birds, mammals. Birds have high metabolic rates (have higher body temperature compared to ours) = increases requirement for energy. Where gas exchange occurs type ii alveolar cells: relatively thick walled. Not efficient in allowing diffusion. Not involved in diffusion. Monitors fluid balance across the walls of the alveoli surfactant secretion: outer surface of alveoli are covered in capillaries. 80- 90% of surface very thin wall capillaries, very thin wall alveoli, very closely together = reducing diffusion distance = efficient system. Lungs would collapse: pleural cavity contains a small volume of pleural fluid. Water is very cohesive resistant in external force. Inhalation: somatic motor neuron firing stimulates inspiratory muscles. Volume of the thorax increases. Intrathoracic pressure decreases boyle"s law volume increases, pressure must decrease. Intrathoracic pressure = intrapleural pressure.
