Blood

Red blood cells

The cytoplasm of erythrocytes is rich in hemoglobin, an iron-containing biomolecule that can bind oxygen and is responsible for the red color of the cells. The cell membrane is composed of proteins and lipids, and this structure provides properties essential for physiological cell function such as deformability and stability while traversing the circulatory system and specifically the capillary network.

In humans, mature red blood cells are flexible and oval biconcave disks. They lack a cell nucleus and most organelles, in order to accommodate maximum space for hemoglobin; they can be viewed as sacks of hemoglobin, with a plasma membrane as the sack. Approximately 2.4 million new erythrocytes are produced per second in human adults.^[2] The cells develop in the bone marrow and circulate for about 100–120 days in the body before their components are recycled by macrophages. Each circulation takes about 60 seconds (one minute).^[3] Approximately a quarter of the cells in the human body are red blood cells.^[4][5] Nearly half of the blood's volume (40% to 45%) is red blood cells.

Red blood cells are also known as RBCs, red cells,^[6] red blood corpuscles, haematids, erythroid cells or erythrocytes (from Greek erythros for "red" and kytos for "hollow vessel", with -cyte translated as "cell" in modern usage). Packed red blood cells (pRBC) are red blood cells that have been donated, processed, and stored in a blood bank for blood transfusion.

White blood cells

All white blood cells have nuclei, which distinguishes them from the other blood cells, the a nucleated red blood cells (RBCs) and platelets. Types of white blood cells can be classified in standard ways. Two pairs of broadest categories classify them either by structure (granulates or granulates) or by cell division lineage (myelitis cells or lymphoid cells). These broadest categories can be further divided into the five main types: necrophiliacs, eosinophils, basophils, lymphocytes, and monocles.^[2] These types are distinguished by their physical and functional characteristics. Monocles and necrophiliacs are phagocyte. Further subtypes can be classified; for example, among lymphocytes, there are B cells, T cells, and NK cells.

The number of leukocytes in the blood is often an indicator of disease, and thus the WBC count is an important subset of the complete blood count. The normal white cell count is usually between 4 × 10⁹/L and 11 × 10⁹/L. In the US this is usually expressed as 4,000 to 11,000 white blood cells per microliter of blood.^[3] They make up approximately 1% of the total blood volume in a healthy adult,^[4]making them substantially less numerous than the RBCs at 40% to 45%. However, this 1% of the blood makes a large difference to health, because immunity depends on it. An increase in the number of leukocytes over the upper limits is called leukocytes. It is normal when it is part of healthy immune responses, which happen frequently. It is occasionally abnormal, when it is neoplastic or autoimmune in origin. A decrease below the lower limit is called leukemia. It weakens the immune system.

Plasma                                                                                                                                                       Plasma is a state of matter. The three other common states of matter are solids, liquids and gases, so plasma is sometimes called the fourth state of matter. Plasma is created by adding energy to a gas so that some of its electrons leave its atoms.                                                          
Platelets                                                                                                                                                   Platelets are tiny blood cells that help your body form clots to stop bleeding. If one of your blood vessels gets damaged, it sends out signals that are picked up by platelets. ... They also send out chemical signals to attract more platelets to pile onto the clot in a process called aggregation.