The average adult has about 4-5 liters
in female and 5-6 liters in male of blood living inside of their body, coursing
through their vessels, delivering essential elements, and removing harmful
wastes. Without blood, the human body would stop working.
Blood is the fluid of life,
transporting oxygen from the lungs to body tissue and carbon dioxide from body
tissue to the lungs. Blood is the fluid of growth, transporting nourishment
from digestion and hormones from glands throughout the body. Blood is the fluid
of health, transporting disease fighting substances to the tissue and waste to
the kidneys.
Blood is a type of connective tissue,
consisting of cells and cell fragments surrounded by a liquid matrix. The cells
and cell fragments are the formed
elements, and the liquid is the plasma.
The formed elements make up about 45%, and plasma makes up about 55% of the
total blood volume. Blood makes up about 8% of the total weight of the body.
Plasma is a pale yellow colored, clear
liquid that is 91% water; 7% proteins; and 2% other substances, such as ions,
nutrients, gases, and waste products. It is also an essential ingredient for
human survival.
It might seem like plasma is less
important than the blood cells it carries. But that would be like saying that
the stream is less important than the fish that swims in it. You can't have one
without the other.
Besides water, plasma also contains
dissolved salts and minerals like calcium, sodium, magnesium, and potassium.
Microbe-fighting antibodies travel to the battlefields of disease by hitching a
ride in the plasma.
Without plasma, the life-giving blood
cells would be left floundering without transportation. Never underestimate the
importance of plasma.
Plasma proteins are proteins found in the blood plasma, the clear, protein-rich
fluid which is left behind when platelets,
red blood cells, and white blood cells are removed from the blood. These
proteins play a number of important roles in the human body, and levels of plasma proteins
are sometimes evaluated in a laboratory analysis to gather information about a
patient's general health and specific health issues which a patient may be
experiencing. Plasma proteins make up around 7% of the
total blood volume, with levels
which can fluctuate at times.
Plasma proteins
include albumin, globulins, and fibrinogen.
·
Albumin acts as a transporter and a regulator
of osmotic pressure
·
Globulins are involved in transport and immune
processes
·
Fibrinogen is primarily involved in blood
clotting
Activation of clotting factors results
in the conversion of fibrinogen into:
o Fibrin is a threadlike protein that
forms blood clots
Serum is plasma without the clotting factors
About 95% of the volume of the formed
elements consist of red blood cells (RBCs), or erythrocytes; white blood cells
(WBCs), or leukocytes; and platelets, or thrombocytes.
The process of blood cell production
is called hematopoiesis.
When a blood vessel is severely
damaged, blood clotting, or coagulation, results in the formation
of a blood clot. A blood clot is a network of threadlike protein fibers, called
fibrin, that traps blood cells, platelets, and fluid.
The formation of a blood clot depends
on a number of proteins, called clotting factors. Most clotting factors are
manufactured in the liver, and many of them require vitamin K for their
synthesis. In addition, many of the chemical reactions of clot formation
require Ca2+ and the chemicals released from platelets. Low levels of vitamin
K, low levels of Ca2+, low numbers of platelets, or reduced synthesis of
clotting factors because liver dysfunction can seriously impair the
blood-clotting process.
1. The extrinsic pathway of clotting
starts with thromboplastin, which is released outside of the plasma in damaged
tissue.
2. The intrinsic pathway of clotting
starts when inactive factor XII, which is in the plasma, is activated by coming
into contact with a damaged blood vessel.
3. Activation of the extrinsic or
intrinsic clotting pathway results in the production of activated factor X.
4. Activated factor X, factor V,
phospholipids, and Ca2+ from prothrombinase.
5. Prothrombin is converted to thrombin
by prothrombinase.
6. Fibrinogen is converted to fibrin by
thrombin.
7. Thrombin activates clotting factors,
promoting clot formation and stabilizing the fabrin clot.
My blood type is O, what’s yours? If
you don’t know, well, here’s how.
Purchase a blood type testing kit. If you or
someone you know happens to work in a medical setting, see if you can get your
hands on one of these tests for free.
·
Dispense
one drop of your blood to each field on the test card. Use a sterilized needle.
The fields contain antibodies, which will provoke a reaction with antigens on
your red blood cells.
·
Use a new
toothpick for each field to mix the blood with the impregnation, creating an
about dime-sized smear.
o If you have blood type A,
clumping will appear in following fields: anti-A
o If you have blood type B,
clumping will appear in the field: anti-B
o If you have blood type AB,
clumping will appear in fields anti-A, anti-B
o If you have blood type O, no
clumping will appear.
Landsteiner
observed two distinct chemical molecules present on the surface of the red
blood cells. He labeled one molecule "A" and the other molecule
"B." If the red blood cell had only "A" molecules on it,
that blood was called type A. If the red blood cell had only "B"
molecules on it, that blood was called type B. If the red blood cell had a
mixture of both molecules, that blood was called type AB. If the red blood cell
had neither molecule, that blood was called type O.
If two
different blood types are mixed together, the blood cells may begin to clump
together in the blood vessels, causing a potentially fatal situation.
Therefore, it is important that blood types be matched before blood
transfusions take place. In an emergency, type O blood can be given because it
is most likely to be accepted by all blood types. However, there is still a
risk involved.
A person
with type A blood can donate blood to a person with type A or type AB. A person
with type B blood can donate blood to a person with type B or type AB. A person
with type AB blood can donate blood to a person with type AB only. A person
with type O blood can donate to anyone.
A person
with type A blood can receive blood from a person with type A or type O. A person
with type B blood can receive blood from a person with type B or type O. A
person with type AB blood can receive blood from anyone. A person with type O
blood can receive blood from a person with type O.
Because
of these patterns, a person with type O blood is said to be a universal donor.
A person with type AB blood is said to be a universal receiver. In general,
however, it is still best to mix blood of matching types and Rh factors.
To understand better ABO Blood Group, here’s a video that
would help you:
Scientists
sometimes study Rhesus monkeys to
learn more about the human anatomy because there are certain similarities
between the two species. While studying Rhesus monkeys, a certain blood protein
was discovered. This protein is also present in the blood of some people. Other
people, however, do not have the protein. The presence of the protein, or lack
of it, is referred to as the Rh (for Rhesus) factor.
If your
blood does contain the protein, your blood is said to be Rh positive (Rh+). If
your blood does not contain the protein, your blood is said to be Rh negative
(Rh-).
This Rh
factor is connected to your blood type. For example, your blood may be AB+
which means that you have type AB blood with a positive Rh factor. Or, you
might have O- blood which means that you have type O blood with a negative Rh
factor.
End of Chapter 16
