Introduction to Blood Vessels
Veins are blood vessels containing blood flowing to the heart, while arteries have blood flowing from the heart. In most diagrams the blue color represents deoxygenated blood and the red color represents oxygenated blood fresh from the lungs.
Heart Anatomy and Function
The heart is composed of four chambers and four valves. The valves—tricuspid, pulmonary, mitral (bicuspid), and aortic semi‑lunar—ensure that blood moves in the correct direction and does not flow backwards.
Blood Flow Through the Heart (Right Side)
Blood from the upper body (head, neck, arms, and chest) enters the heart through the superior vena cava, and blood from the lower body (trunk, viscera, and legs) enters via the inferior vena cava. Both large veins empty into the right atrium. From the right atrium blood passes through the tricuspid valve, which has three flaps, into the right ventricle. The right ventricle pumps the blood out through the pulmonary valve into the pulmonary artery. Although it is an artery, the pulmonary artery is colored blue because it carries deoxygenated blood toward the lungs.
Gas Exchange in the Lungs
The pulmonary artery splits into left and right pulmonary arteries, each traveling to a lung. Inside the lungs carbon dioxide is discarded and oxygen is picked up—a process described as gas exchange.
Blood Flow Through the Heart (Left Side)
Oxygen‑rich blood returns from the lungs through the pulmonary veins into the left atrium. It then moves through the mitral valve (also called the bicuspid valve) into the left ventricle. The left ventricle ejects the blood through the aortic semi‑lunar valve into the aorta.
Distribution of Oxygenated Blood
The aorta, the largest artery, begins with the aortic arch. The arch has three major branches that supply the head and arms. From the arch the aorta continues as the descending aorta, running through the chest and abdomen. In the abdomen the descending aorta splits to supply the pelvis and legs, distributing oxygenated blood to the rest of the body.
Takeaways
- Veins carry blood toward the heart while arteries carry blood away, with blue representing deoxygenated vessels and red representing oxygenated vessels.
- The heart’s four chambers and four valves work together to keep blood moving in one direction and prevent backflow.
- Deoxygenated blood enters the right atrium via the superior and inferior vena cava, passes through the tricuspid valve into the right ventricle, and is pumped into the pulmonary artery toward the lungs.
- In the lungs, carbon dioxide is released and oxygen is absorbed before the oxygen‑rich blood returns to the left atrium through the pulmonary veins.
- The left ventricle pushes oxygenated blood through the aortic semi‑lunar valve into the aorta, which distributes it via the aortic arch and descending aorta to the entire body.
Frequently Asked Questions
Who is Neural Academy on YouTube?
Neural Academy is a YouTube channel that publishes videos on a range of topics. Browse more summaries from this channel below.
Does this page include the full transcript of the video?
Yes, the full transcript for this video is available on this page. Click 'Show transcript' in the sidebar to read it.
Helpful resources related to this video
If you want to practice or explore the concepts discussed in the video, these commonly used tools may help.
Links may be affiliate links. We only include resources that are genuinely relevant to the topic.