Describe the route taken in the blood system by a carbon dioxide molecule from the time it is made in the muscle of the legs until it is exhaled
Answers
The blood absorbs CO2 .The haemoglobin in the blood forms a complex called carboxyhemoglobin. This blood is called de-oxygenated blood.
De-oxygenated blood from muscles enters the right atrium heart through inferior vena cava. As the right atrium contracts the blood flows to right ventricle through the open tricuspid valve.When the ventricle is full the tricuspid valve closes thus preventing back flow of the blood.The ventricles contracts, and the de-oxgenated blood leaves the heart to lungs through two pulmonary veins.
Alveoli in lungs are primary sites of exchange of gases in lungs.The blood from heart enters the lungs and exchange of gases occurs between blood and alveoli of the lungs. It occurs through simple diffusion mainly based on pressure and concentration gradient.At the alveolar site, partial pressure of co2 is low,thus causing the co2 trapped in blood (as bicarbonate) to be released .The co2 thus absorbed by alveoli is exhaled through lungs.