Download 4. White blood cells are necessary for pregnancy.

12 Interesting
Facts about Blood
Blood is the life giving fluid that delivers oxygen
to the cells of the body. It is a specialized type of
connective tissue that consists of red blood cells,
platelets, and white blood cells suspended in a liquid plasma matrix. Did you know
that blood accounts for about 8 percent of your body weight or that blood contains
small amounts of gold? Discover more interesting facts about blood.
1. Not all blood is red.
While humans have red colored blood,
other organisms have blood of
varying colors. Crustaceans, spiders,
squid, octopuses, and some
arthropods have blue blood. Some
types of worms and leeches have
green blood. Some species of marine
worms have violet blood. Insects,
including beetles and butterflies, have
colorless or pale-yellowish blood. The
color of blood is determined by the
type of respiratory pigment used to
transport oxygen via the circulatory system to cells. The respiratory pigment in
humans is a protein called hemoglobin found in red blood cells.
2. Your body contains about a gallon of blood.
The adult human body contains approximately 1.325 gallons of blood. Blood makes
up about 7 to 8 percent of a person's total body weight.
3. Blood consists mostly of plasma.
Blood circulating in your body is composed of about 55 percent plasma, 40 percent
red blood cells, 4 percent platelets, and 1 percent white blood cells. Of the white
blood cells in blood circulation, neutrophils are the most abundant.
4. White blood cells are necessary for
pregnancy.
It is well known that white blood cells are important for
a healthy immune system. What is less known is that
certain white blood cells called macrophages are
necessary for pregnancy to occur. Macrophages are prevalent in reproductive system
tissues. Macrophages assist in the development of blood vessel networks in the ovary,
which is vital for the production of the hormone progesterone. Progesterone plays a
critical part in the implantation of an embryo in the uterus. Low macrophage numbers
result in reduced progesterone levels and inadequate embryo implantation.
5. There's gold in your blood.
Human blood contains metals atoms including iron, chromium, manganese, zinc, lead,
and copper. You may also be surprised to know that blood contains small amounts of
gold. The human body has about 0.2 milligrams of gold that is mostly found in the
blood.
6. Blood cells originate from stem
cells.
In humans, all blood cells originate from
hematopoietic stem cells. About 95
percent of the body's blood cells are
produced in the bone marrow. In an adult,
most of the bone marrow is concentrated
in the breast bone and in the bones of the
spine and pelvis. Several other organs help
to regulate the production of blood cells.
These include the liver and lymphatic system structures such as the lymph nodes,
spleen, and thymus.
7. Blood cells have different life spans.
Matured human blood cells have varying life cycles. Red blood cells circulate in the
body for about 4 months, platelets for about 9 days, and white blood cells range from
a few hours to several days.
8. Red blood cells have no nucleus.
Unlike other types of cells in the body, mature red blood cells do not contain a
nucleus, mitochondria, or ribosomes. The absence of these cell structures leaves room
for the hundreds of millions of hemoglobin molecules found in red blood cells.
9. Blood proteins protect against carbon monoxide poisoning
Carbon monoxide (CO) gas is colorless, odorless, tasteless and toxic. It is not only
produced by fuel burning devices, but is also produced as a by-product of cellular
processes. If carbon monoxide is produced naturally during normal cell functions,
why aren't organisms poisoned by it? Because CO is produced in much lower
concentrations than seen in CO poisoning, cells are protected from its toxic effects.
CO binds to proteins in the body known as hemoproteins. Hemoglobin found in blood
and cytochromes found in mitochondria are examples of hemoproteins. When CO
binds to hemoglobin in red blood cells, it prevents oxygen from binding to the protein
molecule leading to disruptions in vital cell processes such as cellular respiration. At
low CO concentrations, hemoproteins change their structure preventing CO from
successfully binding to them. Without this structural change, CO would bind to the
hemoprotein up to a million times more tightly.
10. Capillaries spit out blockages in blood.
Capillaries in the brain can expel obstructive debris. This debris may consist of
cholesterol, calcium plaque, or clots in the blood. Cells within the capillary grow
around and enclose the debris. The capillary wall then opens up and the obstruction is
forced out of the blood vessel into the surrounding tissue. This process slows down
with age and is thought to be a factor in cognitive decline that occurs as we age. If the
obstruction is not completely removed from the blood vessel, it can cause oxygen
deprivation and nerve damage.
11. UV rays reduce blood pressure.
Exposing a person's skin to the sun's rays reduces blood pressure by causing levels of
nitric oxide to rise in the blood. Nitric oxide helps to regulate blood pressure by
reducing blood vessel tone. This reduction in blood pressure could cut the risks of
developing heart disease or stroke. While prolonged exposure to the sun could
potentially cause skin cancer, scientists believe that very limited exposure to the sun
could increase the risks of developing cardiovascular disease and related conditions.
12. Blood types vary by
population.
The most common blood type in the
United States is O positive. The least
common is AB negative. Blood type
distributions vary by population. The
most common blood type in Japan is
A positive.
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