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What is formed when haemoglobin and oxygen combine in the red blood cells? Identify four features of the alveoli that assist in gaseous exchange - AQA - GCSE Physical Education - Question 15 - 2021 - Paper 1
Question 15
What is formed when haemoglobin and oxygen combine in the red blood cells? Identify four features of the alveoli that assist in gaseous exchange. 1. 2. 3. 4.... show full transcript
Worked Solution & Example Answer:What is formed when haemoglobin and oxygen combine in the red blood cells? Identify four features of the alveoli that assist in gaseous exchange - AQA - GCSE Physical Education - Question 15 - 2021 - Paper 1
Step 1
Step 2
Identify four features of the alveoli that assist in gaseous exchange.
Answer
- Large surface area: The alveoli provide a vast area for gas exchange, maximizing oxygen absorption and carbon dioxide release.
- Moist walls: The inner surfaces of the alveoli are moist, allowing gases to dissolve and diffuse more easily.
- Thin walls: Alveolar walls are either one cell thick, promoting efficient gas exchange due to minimal diffusion distance.
- Surrounded by many capillaries: This dense network of capillaries facilitates rapid exchange of gases between the alveoli and the bloodstream.
Step 3
Explain how air pressure changes occur in the chest cavity allowing exhalation to take place.
Answer
During exhalation, the diaphragm relaxes and returns to a dome shape, reducing the volume of the chest cavity. The intercostal muscles contract, lowering the rib cage and further decreasing the chest capacity. As a result, the pressure within the chest cavity increases. Because of the pressure gradient (higher pressure in the chest compared to outside), air is pushed out of the lungs.