Gaseous Exchange.pptx

Gaseous Exchange The Respiratory System Key terms Diffusion – the movement of gases from where there is a high concentration to a low concentration Partial Pressure (p) – the pressure (quantity) of a specific gas exerted by a specific gas in a mixture of gases. Our focus will be on pO2 (oxygen) and...

Gaseous Exchange The Respiratory System Key terms Diffusion – the movement of gases from where there is a high concentration to a low concentration Partial Pressure (p) – the pressure (quantity) of a specific gas exerted by a specific gas in a mixture of gases. Our focus will be on pO2 (oxygen) and pCO2 (carbon dioxide) Internal & External Gaseous Exchange Internal = blood capillaries Muscle cell External = blood capillaries Alveoli In practice… High pO2 in the alveoli results in O2 moving into the capillaries (where there was a low pO2). High pCO2 in the capillaries, means that CO2 will travel across the membrane wall from to the alveoli (where there was a low pCO2). Gaseous Exchange @ Rest When at rest, the bodies demand for O2 is low. As a result, breathing is slow and shallow. small amount of pO2 and pCO2 to cross the two respiration sites, as a small amount is sufficient for the body to sustain it’s This allows for a state of rest. Gaseous exchange and therefore diffusion, is low. Gaseous Exchange During Exercise demand for O2 is high. deep and fast. When the body is exercising, the result, breathing is large amount of pO2 and pCO2 to respiration sites. As a large amount is required demand for O2 delivery and CO2 removal. This allows for a Gaseous exchange and therefore As a cross the two to meet the diffusion, is high Respirat. ory site The Diffusion Gradient Diffusion gradient – the difference in partial pressure (concentration) from one side of a membrane to another. 100 All gasses measured in mmHg O2 in RED , CO2 in BLUE, Gradient in GREEN arrows Muscle Cell Rest Exercise 80 46 40 5 6 0 40 95 60 40 100 40 Rest 100 Blood Exercise 100 The Bohr Shift The amount of O2 being released from haemoglobin and entering muscle cell is dependent on a process called oxygen dissociation. During exercise the muscle tissue… 1. Increases in temperature 2. Increases production of CO2 (raising pCO2) 3. Increases the production of lactic acid (lowering pH) All three of these factors increase oxyhaemoglobin dissociation. This is known as the Bohr Shift The Bohr Shift During recovery, the oxyhaemoglobin dissociation gradually returns back to resting levels at the muscle tissue… 1.Decreases in temperature 2.Removes CO2 (lowering pCO2) 3.Removes lactic acid (increasing pH) Apply it! Q1: For a performer at rest, describe carbon dioxide diffusion at the alveoli. (3) Q2: Describe the process of internal respiration which allow for more oxygen to be diffused into the muscle cell during exercise. (5)