White blood cells (WBC)

Phagocytes (Left branch):

1) Neutrophil

• Engulf through phagocytosis then die shortly after forming pus

2) Monocyte

Mature in the tissues to form:

1. Macrophages

• Accumulate and reside in organs
• Perform antigen presentation

2. Dendritic cells

• Perform antigen presentation

Lymphocytes (Right branch):

1) T cells

Involved in the cell-mediated response can be divided into:

1. Helper

• Activates T+B cells by releasing chemical messengers (cytokins) after binding to antigen.
• Also release toxic chemicals

2. Killer

• Produce toxic chemicals (e.g, hydrogen peroxide) after binding to a pathogen terminating it.

3. Memory

• Long-living cells
• Are the immunological memory
• Can differentiate into T-killer cells if reinfected

2) B cells

Involved in humoral response can be divided into:

1. Plasma

• Produce antibodies specific to the antigens on the pathogen

2. Memory

• Are the immunologial memory
• Can differentiate into B-plasma cells

Components of the blood

45% cells:

There are 3 cell types:

1. Erythrocytes
2. Leukocytes
3. Platelets

1. Erthrocytes 

• Contain haemoglobin (which have 4 haem groups)
• Quaternary protein
• Carries 4O2 molecules
• High SA:Volume ratio
• Only live 120 days due to lack of nucleus

2. Leukocytes

Can be split further into 2:

1. Granulocytes
2. Agranulocytes

1. Granulocytes:

There are 3 types of granulocytes:

1) Neutrophil

• Has a multi-lobed nucleus 
• Involved in phagocytosis

2) Basophil

• Histamine
• Heparin

3) Eosinophil

• Anti-histamine

2. Agranulocytes

There are 2 types of agranulocytes:

1) Monocytes

• Mature in tissues to become macrophages
• Involved in phagocytosis

2) Lymphocytes

• Release antibodies during the immune response

55% plasma:

This can be broken down into 3 main components:

1. Water (used as a solvent for the dissolved chemicals)
2. Hormones (insulin, glycogen)
3. Plasma proteins (antibodies, clotting proteins, enzymes)

It is also made up of inorganic ions (e.g. sodium ions), Glucose (source of energy for cells), Amino acids (allow cells to make proteins), urea (Excretory waste being transported to the kidney) and some dissolved gases (e.g. O2, CO2, N2).

Serum is the name given to plasma without the plasma proteins