Table of Contents
- Functions of the Blood
- Components of Blood
- Physical Characteristics and Volume
- Plasma
- Formed Elements
- Erythrocytes
- Leukocytes
- Hematopoiesis
- Formation of Red Blood Cells
- Formation of White Blood Cells and Platelets
- Hemostasis
- Blood Groups and Transfusions
- Human Blood Groups
- Blood Typing
- See also
Functions of the Blood
- The blood is a carrier of gases, nutrients, and waste products. The oxygen we carry enters the blood within the lungs and is transported to the cells. Additionally, carbon dioxide is produced by those cells, transported in the blood to the lungs, and expelled. Ingested nutrients, ions, and water are carried by the blood from the digestive tract to the cells, while the waste products of the cells are moved to the kidneys for elimination.
- The blood can perform clot formation. Clotting proteins help stem blood loss when a blood vessel is injured.
- The blood transports processed molecules. Most of its substances are produced in one part of the body and transported in the blood to another part.
- The blood provides protection against foreign substances. Antibodies help protect the body from pathogens.
- The blood transports regulatory molecules. Various hormones and enzymes that regulate body processes are carried from one part of the body to another within the blood.
- The blood maintains body temperature. Warm blood is transported from the inside to the surface of the body, where heat is released from the blood.
- The blood regulates pH and osmosis. Albumin is also an important blood buffer and contributes to the osmotic pressure of blood, which acts to keep water from the bloodstream.
Components of Blood
The components of blood consist of a complex connective tissue in which living blood cells, the formed elements, are suspended.
Physical Characteristics and Volume
Blood is a sticky, opaque fluid with a characteristic metallic taste.
- Color: It depends on the amount of oxygen being carried through the body; the color of blood varies from scarlet (oxygen-rich) to a dull red (oxygen-poor).
- Weight: Blood is heavier than water and about five times thicker, or more viscous, largely because of its formed elements.
- pH: Blood is slightly alkaline, with a pH between 7.35 and 7.45.
- Temperature: The temperature is always slightly higher than body temperature (38 degrees Celsius or 100.4 degrees Fahrenheit).
