The Human Circulatory System

The Role Of Blood Cells In The Immune System & Blood Typing
   First off, blood is made up of seven types of cells:  monocyte, neutrphil, eosinophil, basophil, platelets, macrophage, and erythrocytes.  The biological term for red blood cells is "erythrocytes", and white blood cells are "lymphocytes". 
   Red blood cells are tiny disks that are thin around the centers and thick around the the rims.  The rest of the cells include:  membrane, water, electrolytes, enzymes, and compounds of cellular respiratory system.  The shape is caused by transporting gasses, having the cell membrane placed closer to interior parts where the oxygen and hemoglobin is found, and by 1/3 of the cell being hemoglobin.
   White blood cells defend the body against microorganisms.  There are five different types of white blood cells, and they are all distinguished by their size, staining characteristics, and the shape of the nucleus. 
   The first group of white blood cells has three different types.  It's called grandulocyte,and is two times the size of a red blood cell.  The first type of cell under this group is the neutrophil.  The nucleus of a neutrophil has 2-5 lobes that are connected by thin strands of chromatin.  There's a presence of cytoplasmic granules that stain pinkish in neutral stain.  They account for 54%-62& of the white cells in a normal sample of blood taken.  They destroy small particles by phagocytosis.  The second type of cell in this group is eosinophil.  Eosinophil has cytoplasmic granules that stain deep red in acid stain, and has only two lobes.  These types of cells make up only 1%-3% of the circulating white blood cells.  They break down clots and remove unwanted products out of immune reactions.  The third and final type of cell in this group is called basophils.  Basophils are similar to eosinophil'swith shape and size of the nuclei.  They have less irregularly shaped cytoplasmic granules that stain deep blue in basic stain.  They account for less than 1% of white blood cells.
   The second group of white blood cells has two different types.  It's called agranlocyte.  The first type of cell in this group is called a monocyte.  It is 2-3 times bigger than red cells, and the shape is either round or lobed.  It accounds for 3%-9% of the white cells, and destroys large particles of phagocytosis.  The second type of cell in the agranlocyte group is called a lymphocyte cell.  Lymphocyte cells are just a little bit bigger than red cells, and they account for about 25%-33% of all white cells.
   There are also Helper T cells, which identify germs; Killer T cells, which "kill" the cells alerted by the Helper T cells; and finally, B cells, which make antibodies that cling onto the foreign antigens so that the immune cells can kill them. 
   Something that kills white blood cells is HIV.  It destroys many of the white blood cells, so they can't do their job of protecting us from diseases.  HIV destroys the Helper T cells, which then disables our immune system.  Needless to say, when someone is infected with the HIV virus, their immune system is getting shut down.  Monocytes and macrophages play a major role in HIV.

   With blood typing, there are three alleles:  A, B, and O.  A persons blood type is inherited by their parents on chromosome 9, with one allele from each parent.  Blood type's A & B are codominant, while the O type is recessive.  Therefore, if a person receives the alleles for both A and B, they'll end up with an AB blood type.  Since the O blood type is recessive, it won't show unless both parents pass on O type genes (OO).

The Liver
   Lastly, the liver removes toxins from the body, like poisonous things and damaged red blood cells.  It makes hormones, and it is the largest gland in the body.  There are two types of cells that populate the lives lobes:  parenchymal and non-parenchymal.  There are 500 functions of the liver, each one just as important as the next.  It creates biological chemicals for decomposition, stores glucose, stores glycogen for only a day, is digestive for bial, and regulates the body's metabolism.  It also acts as a storage locker for various minerals and vitamins.