Respiratory System: Gas Exchange and Transport

Gas Exchange and Transport

• The concentration and movement of O2 and CO2 between air, lungs, blood, and tissues are regulated by Fick's Law, Dalton's Law, and Henry's Law.
• Fick's Law describes the diffusion of gases across membranes.
• Dalton's Law states that the total pressure of a gas mixture is the sum of its partial pressures.
• Henry's Law explains the solubility and transport of gases in liquids.

Oxygen and Carbon Dioxide Transport

• Oxygen is primarily carried by haemoglobin in red blood cells, forming oxyhaemoglobin.
• The binding and release of oxygen are influenced by factors such as partial pressure of oxygen and pH.
• Carbon dioxide is transported in three forms: dissolved in plasma, chemically bound to haemoglobin, and as bicarbonate ions.

Importance of Haemoglobin

• Haemoglobin binds to oxygen in the lungs and releases it in tissues, ensuring oxygen reaches all cells.
• Haemoglobin increases the oxygen-carrying capacity of blood, and its affinity for oxygen allows efficient oxygen uptake and delivery.

Respiratory System Structure and Function

• The trachea, bronchi, and bronchioles transport air to the alveoli, where gas exchange occurs.
• The diaphragm and intercostal muscles facilitate breathing.

Role of the C-Shaped Cartilage in the Trachea

• The C-shaped cartilage in the trachea provides support and prevents the trachea from collapsing during breathing.
• The cartilage rings are C-shaped to allow flexibility and accommodate the movement of the oesophagus, which lies behind the trachea.

Roles of the Cells of the Respiratory Zone

• Type I alveolar cells facilitate gas exchange.
• Type II alveolar cells produce surfactant to prevent alveolar collapse.
• Alveolar macrophages protect against pathogens.
• Capillary endothelial cells aid in gas exchange with the bloodstream.

Role of Surfactant

• Surfactant is a substance produced by type II alveolar cells in the lungs.
• Its main role is to reduce surface tension in the alveoli, preventing their collapse during exhalation.

Factors that Govern Diffusion

• Concentration gradient
• Temperature
• Molecular size and weight
• Surface area
• Medium permeability
• Distance

Processes of Respiration

• External respiration: pulmonary ventilation (breathing) and gas exchange in the lungs, where oxygen enters the bloodstream and carbon dioxide is expelled.
• Internal respiration: oxygen transport in the blood to the body tissues, cellular respiration where oxygen is utilized to produce energy, and gas exchange at the tissue level where oxygen is delivered and carbon dioxide is removed.

Respiratory Mechanics

• Pulmonary ventilation, or the process of breathing, is driven by Boyle's law.
• According to Boyle's law, the pressure of a gas is inversely proportional to its volume.

Learn about the concentration and movement of oxygen and carbon dioxide between air, lungs, blood, and tissues, regulated by Fick's Law, Dalton's Law, and Henry's Law.