Final answer:
Systemic circulation delivers blood in parallel, meaning each organ receives its own blood supply through the arterial branches derived from the aorta, allowing for precise control of blood flow based on the organ's needs.
Step-by-step explanation:
When we say the "systemic circulation delivers blood in parallel," we're referring to the way oxygen-rich blood is distributed from the left ventricle of the heart through the aorta and into arteries that branch out to supply various organs and tissues of the body. Each major branch of the systemic circuit delivers blood in parallel to each organ or tissue, meaning each receives its own dedicated supply of blood, allowing for precise control of blood distribution to meet specific metabolic needs.
For example, during exercise, more blood is directed to the skeletal muscles, heart, and lungs, while after a meal, more blood supply is directed to the digestive system. However, the brain always receives a relatively constant blood supply regardless of the activity. The systemic veins then collect the deoxygenated blood from the organs and return it to the heart's right atrium, completing the systemic circulation.