Respiratory & Circulatory

4. blood vessels that carry blood towards the heart
7. a protein made by the liver
8. slippery aqueous secretion produced by and covering mucous membranes
9. an organelle found in eukaryotic cells
10. period of contraction of the ventricles of the heart that occurs between the first and second heart sounds of the cardiac cycle
12. the voice box, is an organ in the top of the neck involved in breathing, producing sound and protecting the trachea against food aspiration
13. substances that cause an immune response in the body by identifying substances in or markers on cells
14. yellowish liquid component of blood that holds the blood cells of whole blood in suspension

1. the main artery that carries blood away from your heart to the rest of your body
2. the proportion, by volume, of the blood that consists of red blood cells
3. the airways that lead from the trachea into the lungs and then branch off into progressively smaller structures until they reach the alveoli, the tiny sacs that allow for the exchange of oxygen and carbon dioxide in the lungs
5. the cartilage in the nose that separates the nostrils
6. a leaf-shaped flap in the throat that prevents food from entering the windpipe and the lungs
11. the part of the throat behind the mouth and nasal cavity