July 24, 2024

Transport of respiratory gases

Transport of respiratory gases

The respiratory system is responsible for the exchange of respiratory gases, primarily oxygen (O2) and carbon dioxide (CO2), between the body and the external environment. The process involves several steps and structures within the respiratory system:

  1. Breathing: The process begins with breathing, which involves the inhalation of oxygen-rich air and the exhalation of carbon dioxide. During inhalation, the diaphragm and intercostal muscles contract, expanding the chest cavity and causing air to enter the lungs. During exhalation, the diaphragm and intercostal muscles relax, allowing for the expulsion of air from the lungs.
  2. External Respiration: Oxygen from the inhaled air enters the alveoli, which are small air sacs located at the ends of the bronchioles within the lungs. Carbon dioxide, on the other hand, moves from the blood into the alveoli. This exchange of gases occurs through a process called diffusion, where gases move from an area of higher concentration to an area of lower concentration across a thin membrane.
  3. Gas Transport in Blood: Oxygen binds to hemoglobin, a molecule within red blood cells, forming oxyhemoglobin. This allows oxygen to be transported through the bloodstream to the body’s tissues. Carbon dioxide produced by cellular metabolism is transported in the blood primarily in three forms: dissolved in plasma, bound to hemoglobin (carbaminohemoglobin), and as bicarbonate ions (HCO3-) formed through a chemical reaction in red blood cells.
  4. Internal Respiration: Within the body’s tissues, oxygen is released from oxyhemoglobin and diffuses into the cells, where it is utilized for cellular respiration. At the same time, carbon dioxide diffuses out of the cells into the bloodstream.
  5. Excretion of Carbon Dioxide: Carbon dioxide is transported back to the lungs through the bloodstream. In the alveoli, it diffuses from the blood into the air sacs and is eliminated from the body during exhalation.

It’s important to note that the respiratory system works in close coordination with the circulatory system to facilitate the transport of respiratory gases. The circulatory system carries oxygenated blood from the lungs to the body’s tissues and returns deoxygenated blood, carrying carbon dioxide, back to the lungs for elimination. This allows for a continuous exchange of respiratory gases, ensuring the body’s cells receive the oxygen they need while removing waste carbon dioxide.

Suggested readings:

First Year Pharm D Subjects Syllabus, Notes, PDF Books, MCQ

1.1Human Anatomy and Physiology
1.3Medicinal  Biochemistry
1.4Pharmaceutical Organic Chemistry
1.5Pharmaceutical Inorganic Chemistry
1.6Remedial Mathematics/ Biology