Pages 26-27 in Life Processes Packet BLOOD & IMMUNITY NOTES Pages 26-27 in Life Processes Packet

What is BLOOD? Blood is a LIQUID tissue that contains dissolved and suspended materials that travel through the BLOOD VESSELS to every part of the body. Each component of blood plays an essential role in the maintenance of HOMEOSTASIS in the body. Blood has three (3) major functions: TRANSPORT REGULATION PROTECTION

Where is blood produced? Blood is produced in BONE MARROW, especially the marrow of the vertebrae, ribs, hips, skull, and sternum.

COMPONENTS OF THE BLOOD Blood is made up of PLASMA RED BLOOD CELLS WHITE BLOOD CELLS PLATELETS An average-sized adult has about 4-6 liters of blood in their body

BLOOD COMPONENTS Plasma is the LIQUID portion of the blood. It is clear and STRAW-colored. Plasma makes up 55% of the blood. 90% of the plasma is made of WATER. The remaining 10% of plasma contains various materials that have been dissolved such as HORMONES, ANTIBODIES, and ENZYMES. The main function of plasma is to TRANSPORT MATERIALS TO MAINTAIN HOMEOSTASIS.

RED BLOOD CELLS RBC’S are a solid portion of the blood. They are scientifically known as ERYTHROCYTES. RBC’s lose their NUCLEUS before being released into the bloodstream. There are approximately FIVE MILLION RBC’s in a drop of blood. RBC’s are DISK-shaped with a THIN center.

RED BLOOD CELLS (continued) RBC’s are RED in color due to the presence of HEMOGLOBIN, a pigment that contains iron. The main function of RBC’s is to CARRY OXYGEN TO CELLS. A blood disease associated with a low RBC count or insufficient hemoglobin is ANEMIA. Anemia results in cells not getting the correct amount of OXYGEN.

WHITE BLOOD CELLS WBC’S are also a SOLID component of blood. WBC’s are scientifically known as LEUKOCYTES. There are several types of leukocytes including LYMPHOCYTES. Some WBC’s can ENGULF foreign invaders, while others make ANTIBODIES which are chemicals that kill pathogens.

WHITE BLOOD CELLS (continued) There are usually 8-10 THOUSAND WBC’s in a drop of blood. The WBC count may INCREASE when the body is fighting off an INFECTION. WBC’s are made in the BONE MARROW as well as the LYMPH GLANDS and THYMUS.

ANTIGEN – Protein that can trigger an immune response ANTIBODY – protein that destroys specific antigens

WHITE BLOOD CELLS (continued) A blood disease associated with WBC’s is LEUKEMIA which is a type of CANCER. Leukemia is characterized by high numbers of abnormal WBC’s. NORMAL BLOOD leukemia

PLATELETS Platelets are a SOLID part of the blood. Platelets are small cell FRAGMENTS that are broken off of large cells found in the bone MARROW. Platelets do not contain any NUCLEI. There are about 300 THOUSAND platelets per drop of blood. PLATELET

PLATELETS The main function of platelets is TO TRIGGER THE CLOTTING OF BLOOD. Blood clotting is an essential process needed to restore homeostasis when bleeding occurs. When injury occurs, the damaged cells release a factor that causes the platelets to get STICKY.

PLATELETS (continued) A person with the genetic disease Hemophilia has enough platelets, but lacks the PROTEINS (ENZYMES) needed to make the platelets sticky. Hemophilia Video