Le système circulatoire

Le système circulatoire est le système d'organes vitaux qui transporte le sang dans tout le corps. Il se compose du cœur et des vaisseaux sanguins. Les vaisseaux sanguins sont divisés en deux groupes : les artères partant du cœur et les veines menant au cœur. Les artères ont le plus souvent du sang oxygéné, tandis que les veines ont le plus souvent du sang désoxygéné. Il y a aussi les capillaires, des vaisseaux sanguins très fins dont le rôle est d'alimenter en sang les cellules les plus isolées de l'organisme.

Notre corps possède deux circuits : le circuit systémique et le circuit pulmonaire.

Systemic circulation:

- Arteries --> oxygenated blood

- Veins --> blood without oxygen

Pulmonary circulation:

- Arteries --> blood without oxygen

- Veins --> oxygenated blood

Cellular respiration

Cellular respiration is the process by which organisms use oxygen and foodstuff to avert the energy in these substances into vital activities and to get rid of waste products (carbon dioxide and water.)

The energy released during the process of breaking down glucose, carbohydrates, fats, and other organic fuel during glycolysis is stored in adenosine triphosphate . Pyruvate molecules produced during glycolysis then enter the mitochondria, where they are converted into acetyl coenzyme A. This compound enters the TCA cycle.

The TCA cycle, also known as the Krebs cycle, is very important in the process of breaking down organic fuel molecules. The cycle is subdivided into eight stages with eight different enzymes that produce energy. Most of the energy is captured and later converted into ATP, which will later be used as a source of energy for our cells. The waste product carbon dioxide is released into the blood and is transported to the lungs to be eliminated. Then the whole process enters the last stage, where electrons are added to oxygen, which leads to the formation of ATP and water as a waste product.

Composition of blood