How Blood Works

There is no substitute for human blood. Everyone needs it to carry nutrients and oxygen throughout the body; to carry carbon dioxide and other waste back to the lungs, kidneys, and liver; to fight against infection; and to help heal wounds.

Each component of blood has a different function, but all components are necessary for health. When people lose blood or can’t produce enough, their lives may depend on volunteer blood donors.

Last year, Michigan Blood collected about 100,000 pints of blood – and someone always needs blood.

Reasons People Need Blood

• Cancer
• Surgery
• Heart and blood vessel disease
• Diseases of the gastrointestinal (GI) tract
• Emergencies (accidental injuries, burns, etc.)

Blood Cells

• Produced in bone marrow
• Vertebrae, ribs, pelvis, skull, and sternum are especially productive cell factories
• Circulated throughout body by plasma, a pale yellow mixture of water, proteins, and salts (plasma also     circulates nutrients, enzymes, and hormones)
• Plasma and the different types of cells that make up blood are called components
• Separated out of whole blood in the laboratory, different components are transfused individually     depending on the patient’s particular medical needs

Red Blood Cells

• Disc-shaped
• Contain hemoglobin
• Pick up and deliver oxygen throughout the body

White Blood Cells

• Defend the body against infection
• Can move out of blood stream and reach tissues where infection threatens

Platelets

• Help control bleeding
• Form clusters to plug small holes in blood vessels and help clotting process