The vasa vasorum is a network of small blood vessels that supply the walls of large blood vessels, such as the aorta and vena cava.
        
             
        
        
        
Answer:
Breathing out the carbon dioxide
Explanation:
Blood is the medium through which carbon dioxide is transported to the lungs from where it is exhaled out. 
The Carbon dioxide produced in cells after respiration diffuses into the blood  in exchange of oxygen delivered to the cells for further respiration. Blood while flowing through the lungs passes carbon dioxide to its alveoli which is then exhaled out and oxygen is inhaled from outside.
Hence, cell keep the carbon dioxide from building up in the cytoplasm and poisoning the cell by exhaling CO2.
 
        
             
        
        
        
Answer:
No to feel nervous is too feel the sense of feeling scared and has nothing to do with the nerves in your body