Gas Exchange, Digestion, and Absorption

• Bronchi have mucus to trap dirt and pathogens.
• Tidal Volume = Pulmonary Ventilation Rate (PVR) / Breathing Rate
• During inspiration, external intercostal muscles contract.
• Elastic fibres allow alveoli to stretch and recoil.
• Exopeptidases hydrolyse peptide bonds at the ends of polypeptide chains to release dipeptides.
• Insects have tracheae which divide into tracheoles.
• Countercurrent flow is when blood and water flow in opposite directions across gill lamellae in fish.
• The diaphragm controls the volume of the thorax.
• Hydrolysis is the main process by which chemical digestion occurs.
• Sucrase is a disaccharidase.
• Micelles are tiny lipid droplets.
• Glucose and amino acids are absorbed in the ileum.
• Bile salts emulsify fats to increase surface area for enzymes.