
1) Heart chambers
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https://www.crosswordclues.com/clue/ventricles

Comparatively large spaces filled with cerebrospinal fluid. Of the four ventricles, three are located in the forebrain and one in the brainstem. The lateral ventricles, the two largest, are symmetrically placed above the brainstem, one in each hemisphere.
Found on
http://www.brainfacts.org/glossary

Chambers of an organ. For example, the four connected cavities (hollow spaces) in the central brain or the four chambers of the heart. ... (12 Dec 1998) ...
Found on
http://www.encyclo.co.uk/local/20973

(ven-trih-kals) In the brain, these are four fluid-filled chambers that form a network with the spin
Found on
http://www.encyclo.co.uk/local/22394

Lower chambers of the heart
Found on
http://www.generalandmedical.com/glossary/index_alpha_Results.html?mode=V

Ventricles: 1, The right ventricle and the left ventricle, the lower two chambers of the heart. 2. Two or more of the four connected spaces within the central portion of the brain.
Found on
http://www.medterms.com/script/main/art.asp?articlekey=26788

The two muscular, lower chambers of the heart, that are primarily responsible for pumping blood out of the heart; also, cavities in the brain within which is produced the cerebrospinal fluid.
Found on
http://www.thehorse.com/Glossary.xhtml?L=V

The two thick-walled, muscular, posterior chambers of the heart; the ventricles receive blood from the atria and then pump it to other parts of the body
Found on
https://academy.allaboutbirds.org/bird-academys-a-to-z-glossary-of-bird-ter

A small cavity or chamber within a body or organ, especially (a) the chamber on the left side of the heart that receives arterial blood from the left atrium and contracts to force it into the aorta, (b) the chamber on the right side of the heart that receives venous blood from the right atrium and forces it into the pulmonary artery, (c) any of the...
Found on
https://www.encyclo.co.uk/local/20528

The two thick-walled lower chambers of the heart
Found on
https://www.encyclo.co.uk/local/20805

Hollow spaces within the brain that are filled with cerebrospinal fluid.
Found on
https://www.neurological.org.nz/resources/glossary
No exact match found.