What is the role of haemoglobin in oxygen transport?

Haemoglobin's role in oxygen transport is to bind with oxygen in the lungs and carry it to body tissues.

Haemoglobin is a protein molecule found in red blood cells, which are responsible for transporting oxygen from the lungs to the rest of the body. It is a complex molecule made up of four protein chains, each of which is attached to a heme group. The heme group contains an iron atom that can bind to one molecule of oxygen, allowing each haemoglobin molecule to carry up to four oxygen molecules.

The binding of oxygen to haemoglobin is a reversible process, meaning it can attach and detach without altering the structure of the haemoglobin molecule. This is crucial for the delivery of oxygen to the body's tissues. When the oxygenated blood reaches the tissues, the oxygen molecules detach from the haemoglobin and are used by the cells for various metabolic processes. The now deoxygenated haemoglobin then returns to the lungs to pick up more oxygen, and the cycle continues.

The ability of haemoglobin to bind and release oxygen is influenced by several factors, including the partial pressure of oxygen, carbon dioxide levels, pH, and temperature. For instance, in the lungs where the partial pressure of oxygen is high, haemoglobin readily binds to oxygen. Conversely, in the tissues where the partial pressure of oxygen is low, haemoglobin releases its bound oxygen. This property of haemoglobin, known as the oxygen-haemoglobin dissociation curve, is vital for efficient oxygen transport and delivery.

In summary, haemoglobin plays a pivotal role in oxygen transport by binding to oxygen in the lungs and carrying it to the body's tissues where it is needed. Its ability to reversibly bind and release oxygen, influenced by various physiological conditions, ensures that oxygen is delivered efficiently to meet the body's metabolic demands.