Iron is an essential element for blood production. About 70 percent of your body’s iron is found in the red blood cells of your blood called hemoglobin and in muscle cells called myoglobin. Hemoglobin is essential for transferring oxygen in your blood from the lungs to the tissues.

All red blood cells contain a red pigment known as hemoglobin. Oxygen binds to hemoglobin, and is transported around the body in that way. In tiny blood vessels in the lung, the red blood cells pick up oxygen from inhaled (breathed in) air and carry it through the bloodstream to all parts of the body.

Oxygen is carried in the blood in two forms: (1) dissolved in plasma and RBC water (about 2% of the total) and (2) reversibly bound to hemoglobin (about 98% of the total).

Oxygen is primarily transported through the blood by erythrocytes. These cells contain a metalloprotein called hemoglobin, which is composed of four subunits with a ring-like structure. Each subunit contains one atom of iron bound to a molecule of heme.

So the correct answer ’25ml’.

A normal person has about 15 grams of haemoglobin per 100 ml of blood. 1 gram of haemoglobin binds about 1.34 ml of O2. Thus on an average 100 ml of blood carries about 20 ml (19.4 ml exactly) of O2 Hence under normal conditions, about 5 ml of oxygen is transported to tissues by 100 ml.

Every 100 ml of oxygenated blood can deliver around 5 ml of O2 to the tissues under normal physiological conditions.

This form transports about 10 percent of the carbon dioxide. When carbon dioxide binds to hemoglobin, a molecule called carbaminohemoglobin is formed. Binding of carbon dioxide to hemoglobin is reversible.

Thus, the correct answer is ‘4%. ‘

Although oxygen dissolves in blood, only a small amount of oxygen is transported this way. Only 1.5 percent of oxygen in the blood is dissolved directly into the blood itself. Most oxygen—98.5 percent—is bound to a protein called hemoglobin and carried to the tissues.

The oxygen in inhaled air passes across the thin lining of the air sacs and into the blood vessels. This is known as diffusion. The oxygen in the blood is then carried around the body in the bloodstream, reaching every cell.

Delivery to organs and tissues The amount of diffusive oxygen movement depends on the oxygen tension gradient and the diffusion distance. In many critically ill patients tissue hypoxia is due to disordered regional distribution of blood flow both between and within organs.

The arteries and veins carry blood throughout the body, delivering oxygen and nutrients to the body tissues and taking away tissue waste matter.

The arteries and veins carry blood around the body. They send oxygen and nutrients to the body tissues. And they take away tissue waste.