Video Transcript
Blood is an example of special
connective tissue. What is the main function of
blood? (A) To bind different tissues of
the body together. (B) To regulate the contractions of
the heart and maintain a regular cardiac cycle. (C) To support and move the bones
of the body. (D) To transmit electrical impulses
from receptors to effectors. Or (E) to transport substances,
including products of digestion and waste materials, around the body.
As the question indicates, blood is
a type of connective tissue. This means it is composed of living
cells suspended within a nonliving matrix. Most types of connective tissue
also contain fibers. Some specialized connective
tissues, however, like blood, do not contain fibers. In blood, the cells include red and
white blood cells. And the nonliving matrix is the
liquid plasma that the cells are suspended in.
So, what is blood for? Well, the red blood cells carry
oxygen from the lungs to all of the cells of the body that need oxygen in order to
conduct cellular respiration or use food products like glucose for energy. They also help carry the waste
carbon dioxide from cellular respiration back to the lungs so that it can be exhaled
out of the body.
White blood cells, which are also
carried in the blood, are important in the immune system. For example, multiple types of
white blood cells are involved in attacking and destroying foreign possibly
pathogenic cells or other substances that they encounter. And the liquid plasma that blood
cells are suspended in not only carries those cells and allows them to be
transported relatively easily around the body, but also carries nutrients absorbed
from food in the intestines and hormones produced from various glands around the
body.
Basically, the blood is a rapid
transport system for many types of molecules and cells that need to be moved
relatively quickly around the body. So, the correct answer to the
question is (E). The main function of blood is to
transport substances, including products of digestion and waste materials, around
the body.
