Grade 10 Biology: Respiration

Grade 10 Biology: Respiration

• Respiration in Living Things: A biological process involving the exchange of gases (oxygen and carbon dioxide) between an organism and its environment. This process is crucial for energy production.
• Human Pulmonary Respiration: The specific process of respiration in humans, involving the lungs.
• Breathing: The process of gas exchange in organisms, including humans. It involves taking in oxygen and releasing carbon dioxide. Breathing ensures the supply of oxygen and the elimination of carbon dioxide.
• Respiratory System: The system in the human body responsible for pulmonary (lung) respiration. The path involves:
  • Nasal Cavities/Mouth: Air enters the body.
  • Pharynx: The throat.
  • Larynx: The voice box.
  • Trachea: Carries air to the lungs.
  • Bronchi: Branches of the trachea leading to the lungs.
  • Bronchioles: Smaller branches of the bronchi.
  • Alveoli: Tiny air sacs in the lungs where gas exchange occurs.
  • Lungs: The main organs of respiration.
  • Diaphragm: A muscle crucial for inhaling and exhaling.
• Inhalation (Breathing In): The process of taking air into the lungs. The muscles of the rib cage raise, the diaphragm contracts and moves downward, increasing the volume of the chest cavity, which causes air to enter the lungs.
• Exhalation (Breathing Out): The process of releasing air from the lungs. The muscles of the rib cage lower, the diaphragm relaxes and moves upward, decreasing the volume of the chest cavity, which forces air out of the lungs.
• Pathway of Inhaled Air: Air enters via nasal cavities/mouth, then passes through the pharynx, larynx, trachea, bronchi, bronchioles, and finally into the alveoli where gas exchange takes place.
• Pathway of Exhaled Air: Air travels from the alveoli, bronchioles, bronchi, trachea, larynx, pharynx, to exit via the nasal cavities or mouth.
• Composition of Inhaled and Exhaled Air:
  • Inhaled Air: Approximately 78% nitrogen, 21% oxygen, 0.03% carbon dioxide.
  • Exhaled Air: Approximately 78% nitrogen, significantly less than 21% oxygen, and approximately 4% carbon dioxide.
• Gas Exchange in Alveoli: Oxygen from the inhaled air diffuses into the blood, while carbon dioxide from the blood diffuses into the alveoli to be exhaled.
• Reasons for Differences in Composition: The blood absorbs oxygen and the body generates carbon dioxide through metabolic processes.