Topic 6 Continued: 6.4 Respiratory System

Distinguish between Ventilation, Gas
Exchange and Cell Respiration
• Ventilation – pumping fresh air or water to the gas exchange surface to replace the air or water already there = maintains conc. Gradients
• Gas X-change – the process of absorbing one gas from the environment and releasing another one
• C.R. – C
6
H
12
O
6
+ 6O
2
 6CO
2
+ 6H
2
O + 36ATP

Explain the need for a ventilation system
• In order to maintain high concentration gradients in the alveoli

Describe the features of alveoli that adapt them for gas exchange

• Walls of alveoli (hundreds of million in both lungs total) are one epithelial layer thin = HUGE
S.A.
• Alveolar capillary walls are one epithelial layer thin
• Both make for easy diffusion
• Surfactant – a natural detergent that prevents adjacent alveoli from sticking together and this liquid also allows for the gases to dissolve
• A dense network of capillaries

Draw and label a diagram of the ventilation system, including trachea, lungs, bronchi, bronchioles and alveoli

Explain the mechanism of ventilation of the lungs in terms of volume and pressure changes caused by the internal and external muscles, the diaphragm and abdominal muscles