Blood: Composition ( Plasma, RBC, WBC, Platelets) and Grouping , Rh Factor

Blood

Blood is a fluid connective tissue in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells. Blood is made up of blood plasma and various cells also called corpuscles

Blood = Plasma + Corpuscles (cells)

These cells include Red Blood Corpuscles (RBC), White Blood Corpuscles (WBC) & platelets

Corpuscles (cells) = RBC + WBC + Platelets

Blood has a pH of 7.4 and accounts for 7% of the human body weight. The average adult has a blood volume of roughly 5 liters.

Composition and Function of Blood

Blood cells are made in the bone marrow and in the spleen. The bone marrow is the soft material in the middle of bones. Special cells in the bone marrow make most of the blood cells in your body.

Plasma proteins are made mostly by the liver.

Plasma

About 55% of blood is blood plasma, a fluid that is the blood's liquid medium, which by itself is straw-yellow in color. The blood plasma volume totals of 2.7–3.0 liters in an average human. It is essentially an aqueous solution containing 92% water, 8% blood plasma proteins, and trace amounts of other materials.

Functions

Plasma circulates dissolved nutrients, such as glucose, amino acids, and fatty acids (dissolved in the blood or bound to plasma proteins), and removes waste products, such as carbon dioxide, urea, and lactic acid.

RBC (erythrocytes)

Count: 4.7 to 6.1 million (male), 4.2 to 5.4 million (female) per cubic mm. of blood
Manufactured in: Red Bone Marrow
Life Span: 120 days
Function: Red blood cells contain the blood's hemoglobin, which gives blood its red color and transports oxygen and carbon dioxide.

Mature red blood cells lack a nucleus and organelles in mammals. By volume, the red blood cells constitute about 45% of whole blood

WBC (Leucocytes)

Count: 4,000–11,000 per cubic mm. of blood
Manufactured in: Red Bone Marrow
Life Span: 3 - 4 days
Function: White blood cells are part of the body's immune system; they destroy and remove old or aberrant cells and cellular debris, as well as attack infectious agents (pathogens) and foreign substances. The cancer of leukocytes is called leukemia.

Platelets (thrombocytes)

Count: 200,000–500,000 per cubic mm. of blood
Manufactured in: Red Bone Marrow
Life Span: average life is 8 - 9 days
Function: They take part in blood clotting (coagulation).

Blood Grouping

Karl Landsteiner is the founder of Blood Grouping. A,B and O blood group was discovered by him while AB blood group was discovered by Decastello and Sturli.

A blood group (Blood Type) is a classification of blood based on the presence or absence of inherited antigenic substances on the surface of red blood cells (RBCs). These antigens may be proteins, carbohydrates, glycoproteins, or glycolipids, depending on the blood group system.

A total of 32 human blood group systems are now recognized by the International Society of Blood Transfusion (ISBT). The two most important ones are ABO and the RhD antigen. They determine someone's blood type (A, B, AB and O, with + and − denoting RhD status).

ABO Blood Group System

The ABOsystem is the most important blood-group system in human-blood transfusion. The associated anti-A and anti-B antibodies are usually immunoglobulin M, abbreviated IgM, antibodies. ABO IgM antibodies are produced in the first years of life by sensitization to environmental substances such as food, bacteria, and viruses. The O in ABO is often called 0 (zero, or null) in other languages.

Rh Blood Group System

The Rh system (Rh meaning Rhesus) is the second most significant blood-group system in human-blood transfusion with currently 50 antigens. The most significant Rh antigen is the D antigen. The presence or absence of the Rh antigens is signified by the + or – sign. For example the A− group does not have any of the Rh antigens.

Red blood cell compatibility

Blood group AB

Individuals have both A and B antigens on the surface of their RBCs, and their blood plasma do not contain any antibodies against either A or B antigen. Therefore, an individual with type AB blood can receive blood from any group (with AB being preferable), but cannot donate blood to any group other than AB. They are known as universal recipients.

Blood group A

Individuals have the A antigen on the surface of their RBCs, and blood serum containing IgM antibodies against the B antigen. Therefore, group A individual can receive blood only from individuals of groups A or O (with A being preferable), and can donate blood to individuals with type A or AB.

Blood group B

Individuals have the B antigen on the surface of their RBCs, and blood serum containing IgM antibodies against the A antigen. Therefore, a group B individual can receive blood only from individuals of groups B or O (with B being preferable), and can donate blood to individuals with type B or AB.

Blood group O

This blood group is also called blood group zero in some countries. Individuals do not have either A or B antigens on the surface of their RBCs, and their blood serum contains IgM anti-A and anti-B antibodies against the A and B blood group antigens. Therefore, a group O individual can receive blood only from a group O individual, but can donate blood to individuals of any ABO blood group (i.e., A, B, O or AB). So, this blood group is called universal donor.

Recipient	Donor
Recipient	O−	O+	A−	A+	B−	B+	AB−	AB+
O−	Yes	No	No	No	No	No	No	No
O+	Yes	Yes	No	No	No	No	No	No
A−	Yes	No	Yes	No	No	No	No	No
A+	Yes	Yes	Yes	Yes	No	No	No	No
B−	Yes	No	No	No	Yes	No	No	No
B+	Yes	Yes	No	No	Yes	Yes	No	No
AB−	Yes	No	Yes	No	Yes	No	Yes	No
AB+	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes

Plasma Compatibility

Recipients can receive plasma of the same blood group, but otherwise the donor-recipient compatibility for blood plasma is the converse of that of RBCs: plasma extracted from type AB blood can be transfused to individuals of any blood group; individuals of blood group O can receive plasma from any blood group; and type O plasma can be used only by type O recipients.

Recipient	Donor
Recipient	O	A	B	AB
O	Yes	Yes	Yes	Yes
A	No	Yes	No	Yes
B	No	No	Yes	Yes
AB	No	No	No	Yes