Video Transcript
What is the primary method for
removing carbon dioxide from the human body? (A) Exhaling it from the lungs, (B)
secreting it from the skin, (C) excreting it in urine, (D) excreting it in
feces.
This question is asking us about
carbon dioxide, which is a waste product of cellular respiration. Before answering this question,
let’s first describe what waste products are and some ways that they can be removed
from the body.
Metabolism is the sum of all
chemical reactions in the body. These reactions are important for
almost every process ranging from the breakdown of food molecules for energy to the
synthesis of biological macromolecules. These chemical reactions can
produce products that aren’t always useful for the human body or are sometimes
toxic. These are known as waste
products.
Here are some examples of some
waste products produced by the body. Excess ions can be filtered out
into urine by the kidneys. Ammonia is produced as a waste
product from the breakdown of amino acids in proteins. This toxic compound can be
converted into a less toxic compound called urea by the liver. Carbon dioxide is produced by a
process called cellular respiration. This is where glucose from the food
we eat is converted into carbon dioxide and water. In this process, energy is
extracted and is used to power the different activities of our body and its
cells. This carbon dioxide diffuses into
the blood and is exhaled by the lungs. All of these organs contribute to
our excretory system and are responsible for maintaining the body’s homeostasis.
Going back to our question, the
primary method for removal of carbon dioxide from the body is given by answer choice
(A), exhaling it from the lungs.
