Blood is an essential aspect or fluid of the body involved in circulation, nutrients, waste, healing, and much more.

It is composed of blood cells, plasma, water, proteins, glucose, oxygen, carbon dioxide, hormones, minerals, broken down products, and more.

Plasma is about 55% of the volume.

Water takes up 90% of the volume.

Blood Cells – Red blood cells (RBCs), White blood cells (WBCs), and platelets.

The RBC and WBC can be broken down into more specific cells.

Hemoglobin – an iron containing protein which helps transport oxygen and allows its solubility.

The “redness” is caused by hemoglobin binding to oxygen. The “darkness” or “blueness” of the occurs when hemoglobin when the cells are deoxygenated. It accounts for 7% of the body’s weight. An adult has an average of 5 Liters.

Typical Function

–  When blood without oxygen reaches the lungs – it becomes oxygenated that is then pumped from the Heart throughout the body.

–  Allows for nutrients to be shipped, moved, and transported around the body.

–  Allows for hormones to be shipped, moved, and transported around the body.

–  Facilitates the removal of waste products such as Carbon Dioxide, Urea, Lactic acid and more.

–  Allows for coagulation, a reaction that occurs when blood transforms from a liquid to a solid due to injury, Inflammation, and more.

–  Helps regulate the pH of the body

–  Helps regulate the core temperature of the body.

–  Helps regulate the immunological function of the Immune System of the body including circulation of immunological cells such as WBC.

–  Helps allow for the detection of foreign material by antibodies.

–  Helps control blood pressure, kidney function, heart function, and many more medical requirements.

–  Hydraulic Function – It can cause engorgement or other changes in the tissue or skin directly related to the blood.

Normal Parameters of Blood

1.)  Hematocrit

–  Men: 38-52%
–  Women: 37-47%

2.)  pH

–  7.35-7.45

3.)  Base excess

–  -3 to +3

4.)  PO2

–  80-100 33 Hg

5.)  PCO2

–  35-45 mm Hg

6.)  HCO3

–  21-27 mM

7.)  Oxygen Saturation

–  Oxygenated: 98-99%
–  Deoxygenated: 75%

Oxygen Transport

–  Oxygen + Hgb for oxygen transport
–  Hemoglobin is the primary transport mechanism.
–  Normally blood leaves the lungs at 98-99% saturation
–  Increased oxygen consumption is seen during sustained exercises.

Carbon Dioxide Transport

–  Carried in the blood in three ways
–  1.)  Converted to bicarbonate by the enzyme carbonic anhydrase – CO2 + H2O —>H2CO3 —> H+ + HCO3
–  2.)  Dissolved in the plasma – less than 10%
–  3.)  Binds to Hemoglobin – less than 25%
–  When CO2 binds to hemoglobin – that cell has a decreased amount of oxygen that is bound.

Production and Break Down of Blood Cells

–  Blood is made in Bone Marrow in a process called Hematopoiesis.

–  This includes Erythropoiesis the process to make red blood cells (RBCs).

–  This also includes Myelopoiesis the process to make white blood cells (WBCs).

–  During childhood – almost all human bones produce RBCs

–  Adults – RBC production is limited to larger bones: Vertebrae, breastbone, ribcage, pelvic bone, bones of arms and legs.

–  Healthy RBC or erythrocytes have a life of about 120 days.

–  Degradation or breakdown occurs in the Spleen and the Liver.

Medical Complications Related to Blood

–  Anemia
–  Sickle-cell anemia
–  Hemophilia
–  Leukemia
–  Polycythemia vera
–  Essential Thrombocytosis
–  Thrombophilia
–  Myelodysplastic syndromes
–  HIV
–  Hepatitis
–  Bacteremia or Sepsis
–  Malaria
–  Trypanosomiasis
–  Carbon Monoxide poisoning
–  And more