Gaseous exchange and lung volumes Learning Objectives: To understand the concept of partial pressures of gases. To understand the concept of partial pressures of gases. To know how gaseous exchange takes place. To know how gaseous exchange takes place. Define the terms minute ventilation, tidal volume and respiratory frequency. Define the terms minute ventilation, tidal volume and respiratory frequency.

Recap test. With the person next to you answer this question: Describe the effect a life long commitment to sport has on the cardiovascular system.[5].

Where does gaseous exchange take place in our body? The exchange of O2 and CO2 occurs in two places known as external respiration (lungs-blood) and internal respiration (blood-tissue). Gaseous exchange relies on a process called d-ff-s-on. “The movement of gases from an area of high concentration to an area of low concentration”.

The difference in between high and low pressure is called a diffusion gradient. The bigger the gradient, the greater the gaseous exchange. Task. Write your own explanation of a pressure gradient and how gases move around.

Partial pressure.... Partial pressure is the pressure a gas exerts within a mixture of gases. E.G. the greater the concentration of gas the greater the partial pressure will be. Were can we see diffusion gradients within our body?

External (Alveoli) respiration... Inspired air = high PP of O2 and low PP of CO2. Pulmonary (Alveoli) capillaries = high PP of CO2 low PP of O2 (deoxygenated blood). Because of this what will happen between the two gases?

Internal respiration... Haemoglobin has lots of O2 and little Co2. When Haemoglobin reaches the muscles O2 diffuses from the muscles into the Myo- lob-n which is then used to produce energy. At the same time Myoglobin gives Haemoglobin its Co2.

Past exam questions.... Explain how gas is exchanged between the blood and the muscle tissues during exercise. Why is this beneficial to performance? [5] Answer: Diffusion gradient. Partial pressures. Differences in O2/Co2 concentrations. Single cell walls. Haemoglobin/Myoglobin. Faster uptake of O2. Etc.

Lung volumes. Task: Using your book/research research minute ventilation, tidal volume and respiratory frequency. Using your book/research research minute ventilation, tidal volume and respiratory frequency. Identify the changes that take place during exercise. Identify the changes that take place during exercise. Complete the graph showing the changes in tidal volume from rest, exercise and recovery. Complete the graph showing the changes in tidal volume from rest, exercise and recovery.