Answer to Question #182801 in Human Anatomy and Physiology for Stephen Villafranca

Question

What is the pathway of Carbon Dioxide from the brain cells to the nose?

Answer 1

What is the pathway of Carbon Dioxide from the brain cells to the nose?

           The brain cells are supplied with nutrients and oxygen through a network of blood vessels which also transport waste materials from these cells to be excreted out of the body. Blood rich in Carbon dioxide (CO₂) from the cerebrum, cerebellum, and brainstem drain into various veins which together drain into Dural venous sinuses. Dural venous sinuses are made up of eleven venous sinuses which is made up of; the superior, inferior, and sagittal sinuses which converge at the confluence of sinuses. From the confluence is the transverse sinus that curves into the sigmoid sinus and drains into the internal jugular vein (Mitsuhashi et al.,2016). The cavernous sinus takes blood from the ophthalmic veins and drains into the internal jugular vein.

           The venous system of the brain can be divided into superficial and deep systems. The superficial system is made up of the superficial cerebral veins, superficial middle cerebral vein, inferior cerebral vein, superior anastomotic veins, and inferior anastomotic veins which all drain their blood into the sinuses system. The deep system is comprised of the subependymal veins and medullary veins that drain into the straight sinus and subependymal veins respectively. Both the superficial and deep systems carry blood rich in waste including CO₂ into the Dural venous sinuses which eventually drain into the jugular vein which later drain the blood into the superior vena cava into the heart (Walsh et al, 2020). The blood rich in CO₂ is pumped into the lungs to be oxygenated again, due to the pressure difference of carbon dioxide in capillary and alveoli, CO₂ diffuses out of the capillary into alveoli then into bronchioles, bronchus, then into the trachea and expelled out through the nose.

 

References

Mitsuhashi, Y., Hayasaki, K., Kawakami, T., Nagata, T., Kaneshiro, Y., Umaba, R., & Ohata, K. (2016). Dural Venous System in the Cavernous Sinus: A Literature Review and Embryological, Functional, and Endovascular Clinical Considerations. Neurologia medico-chirurgica, 56(6), 326–339. <span style="color: black;">https://doi.org/10.2176/nmc.ra.2015-0346</span>

Walsh, D. R., Lynch, J. J., O'Connor, D. T., Newport, D. T., & Mulvihill, J. (2020). Mechanical and structural characterization of the Dural venous sinuses. Scientific reports, 10(1), 21763. <span style="color: black;">https://doi.org/10.1038/s41598-020-78694-4</span>