# Heart Heart is pumping blood and oxygen into body parts. One of its main role is actually to send oxygen contained in the circulatory system into each body parts reserve connected to it. ## Sending oxygen to body parts On each pulse, heart send oxygen to each **connected** body parts. Connected body parts are all parts linked to heart through a chain of circulatory layers present in adjacent body parts, including internal ones. Heart uses the **body part parent hierarchy** to decide what is connected to it. Indeed, on human, the torso is the root of the body part parent hierarchy. Heart should check then what are the children of the torso to know which body parts are connected to it. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://ss3d.gitbook.io/design/entities/health/body-systems/organs/heart.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.