EXPLAIN THE TRANSPORT OF OXYGEN AND CARBON DIOXIDE IN THE BLOOD

• Air( carrying oxygen) is inhaled and enters the lungs
• Travels through the lungs to the alveoli, oxygen is diffused out of the air, and into the surrounding capillaries.
• The oxygen binds with the haemoglobin of the RBCs to form oxyhaemoglobin
• The newly oxygenated blood enters the pulmonary circulation system, which leads from the lungs to the heart.
• The blood enters the left side of the heart from the pulmonary vein into the left atrium, and down past the bicuspid valve into the left ventricle
• From here, the blood is pumped out of the heart past the aortic valve into the aorta.
• The aorta is the largest blood vessel of delivery of oxygenated blood to the body. At this point the blood is on the pathway of systemic circulation. Here the blood goes around the body to where it is needed. Through arteries, arterioles and capillaries.
• At this point, of being in the capillaries, it will eventually reach cells that require oxygen for cellular respiration
• The oxygen diffuses out of the capillaries and into cells, at this point carbon dioxide diffuses into the blood. This carbon dioxide is converted to carbonic acid. The blood in now deoxygented blood.
• The blood carries on its journey in the capillaries but this time it enters the venules, and veins making its way back towards the heart
• Blood enters the right side of the heart by the vena cava (inferior or superior). Into the right atrium, and then past the tricuspid valve into the right ventricle.
• It is pumped out of the heart, past the pulmonary valve to the pulmonary artery.
• From here the blood goes to the lungs ending up in the capillaries surrounding the alveoli.
• This is the point of gaseous exchange; the carbon dioxide is diffused out of the blood into the alveoli. From here the carbon dioxide is released into the air passageway of the lungs for exhalation. Oxygen is diffused out of the alveoli into the capillaries surround the alveoli.

This is the beginning of another circle of new freshly oxygenated blood entering the body, going to the heart, around the body to be taken where needed for respiration. At this point carbon dioxide will diffuse into the blood this is taken to the heart and then to the lungs to be diffused out of the body by exhalation for the whole process to begin again and again.