All of the blood from the body is eventually collected into the two largest veins: the superior vena cava, which receives blood from the upper body, and the inferior vena cava, which receives blood from the lower body region.Tags: How To Write A Persuasive Speech IntroductionHow To Write A Application Letter For NursingCulver City High School HomeworkSummary Business Plan ExampleCreative Writing Titles For Grade 3Optimal Design Of Experiments A Case Study Approach Review
When the ventricle contracts, the blood is pushed into the pulmonary artery that branches into two main parts: one going to the left lung, one to the right lung.
The fresh, oxygen-rich blood returns to the left atrium of the heart through the pulmonary veins.
In the pulmonary loop, the blood circulates to and from the lungs, to release the carbon dioxide and pick up new oxygen.
The systemic cycle is controlled by the left side of the heart, the pulmonary cycle by the right side of the heart.
Then they close, so the blood cannot flow backwards into the atria.
With this system, blood always flows in only one direction inside the heart. Every time the heart beats it goes thump against the chest wall. The pointed tip at the bottom of the heart touches the front wall of the chest.Blood can flow from the atria down into the ventricles because there are openings in the walls that separate them.These openings are called valves because they open in one direction like trapdoors to let the blood pass through.The heart is a pump whose walls are made of thick muscle.They can squeeze (contract) to send blood rushing out.The capillaries have extremely thin walls so that the blood that they carry can come into close contact with the body tissues.The tiny red blood cells can then pass easily through the walls of the capillaries to deliver the oxygen they carry to nearby cells.From here the blood begins its journey through the pulmonary cycle.From the right atrium the blood descends into the right ventricle through the tricuspid valve.