Blood, heart and lungs

This lesson asks you to describe how systems of the human body interact and to explain why these interactions are necessary for survival. The museum offers one medieval physician's account of how blood passes through the lungs between the two sides of the heart; the systems as they are taught today, and the reasons the interaction is necessary, are for your class. ¹

The expectations ask you to name the systems, say how they meet and explain why the meeting matters. Draw the route of the blood as a loop and mark the point where it meets the lungs.

Read one passage slowly. In his commentary on the anatomy of Ibn Sina's Canon, Ibn al-Nafis writes that the blood, once refined in the right cavity, must pass to the left cavity, where the spirit is generated. But there is no passage between the two cavities, because "the substance of the heart is solid in this region and has neither a visible passage, as was thought by some persons, nor an invisible one which could have permitted the transmission of blood, as was alleged by Galen." ² The passage is on folio 46 recto, and West quotes it in Max Meyerhof's translation ². Notice the two kinds of passage he rules out, one visible and one invisible, and who he says held each idea. The record of the pulmonary circulation has the rest.

West gives an aim for the commentary. Ibn al-Nafis did not set out to write a book of his own; his aim was to explain Ibn Sina's anatomy ³. When he reached the heart, he departed from Ibn Sina and from Galen before him, and wrote that anatomy refutes those who claimed the septum was porous ³. The record reports no other reason.

It is easy to think that one correction swaps a whole old picture for a whole new one. The record keeps two questions apart. West describes three kinds of spirit in Galen's historical model, which is not accepted modern physiology ⁴. The route of the blood and the explanation of its function must be told apart: a correction concerning passage can coexist with inherited spirit terminology ⁴. Modern explanation should neither erase the writer's language to make his text contemporary nor let inherited vocabulary cancel the particular anatomical claim about lung and septum ⁴.

The pulmonary circulation is the blood's route from the right side of the heart to the lungs and from the lungs to the left side ², yet the same text keeps the old language of spirit ⁴. Take a position and answer the strongest objection to it: does a correct route for the blood, with an inherited explanation of its work, show that Ibn al-Nafis understood how two body systems interact, and why?

• The pulmonary circulation: the three parts of the account, the two passages West quotes, and what later writers said.
• Ibn al-Nafis: what the biographical entry says about his work and his book.
• Anatomy: what Ibn al-Nafis says about relying on earlier writers for the forms of the organs.
• The Canon of Medicine: the book whose anatomy his commentary explains.

Read about the pulmonary circulation. Draw the heart as two sides with a wall between them, and mark the route the record describes for the blood.