Blood is the fluid that transports substances around the body.
Its job is to “nourish and cleanse each living cell.” ( In His Image , Brand and Yancey, p.59)
Consists of cells suspended in plasma (liquid)
Red blood cells (erythrocytes)
Round cells that carry oxygen
Contain hemoglobin , an iron-containing protein that binds oxygen very strongly in lungs, then releases it in oxygen-poor environment of the capillaries
Don’t have a nucleus
Live about 120 days
Made in the bone marrow
We make about 2 million new RBC per second
Normally have about 5 million RBC in speck of blood the size of a letter “o”
White blood cells (leukocytes)
Several different types, all part of immune system
Defend the body against disease (bacteria, viruses fungi worms), toxins and cancer
Many act by surrounding and engulfing invaders
When infection present in the body, WBC count increases to combat it. Doctors measure WBC levels to determine presence and extent of infections.
More Than Meets the Eye
Platelets – small fragments of WBC that help form blood clots when a blood vessel is damaged.
Platelets stick to wound site, attract more platelets
Clotting proteins circulating in blood become activated
Fibrin becomes activated by clotting factors, forms a network of threads (like a spiderweb) that traps more platelets and RBC to form a clot
Plasma – watery fluid containing cells and dissolved molecules like proteins, oxygen, carbon dioxide, nutrients (glucose, amino acids and fats), waste products (like urea) and hormones
End of Chapter 7
Introduction (slide 2 for me)
Talked about how cells move substances across cell membranes
Respiratory system brings oxygen into the body, gets rid of carbon dioxide
Excretory system removes wastes from cells
Goals for this unit: (Slide 4 for me)
Know what the circulatory system is.
Know the components of the system
What the circulatory system does.
How each of the components contributes to the overall function of the whole.
What are some of illnesses that result from problems in the circulatory system? (You will get this from the written assignment you’re doing.)
Patients requiring blood almost never receive transfusions of whole blood. Instead, a patient typically receives only the components necessary to treat their clinical condition. Therefore, whole blood donations must be processed to separate out each component. Each component plays a different role in the health and survival of a patient. Red blood cells comprise 40-50% of blood volume. They carry oxygen to vital organs and are required by surgical patients who lose blood during surgery or by trauma victims who have lost blood as a result of an accident or injury. Red blood cells that have been donated can be stored in a refrigerator for up to 42 days. If they are not used within six weeks, they must be thrown away. They can also be stored frozen for up to 10 years. Red cells are the most commonly transfused blood component and most whole blood collections are done with the specific intent of capturing the red cell component. Red Blood Cells carry oxygen to organs. Platelets account for a small percentage of whole blood volume. They are used therapeutically to control bleeding and are often transfused in multiple doses to cancer patients undergoing chemotherapy. Platelets must be stored at room temperature to retain their visibility. Therefore, they have only a five day shelf life before they must be discarded due to possible growth of bacteria. Platelets aid in clotting. Plasma: The remainder of blood volume is plasma, a watery substance in which proteins that trigger blood clotting mechanisms are suspended. Plasma can be transfused directly to a patient, but, more often, plasma is used as a raw material for pharmaceuticals. Plasma is “fractionated” into its different protein components, which are then manufactured into pharmaceuticals. Factor VIII, which is required by hemophiliacs to control bleeding, is one such plasma derived medicine. Plasma can be stored frozen for up to one year. Plasma: the fluid portion of blood.
Anemia – too few RBC, can’t carry enough oxygen. Person gets very tired, prone to infections. Treat with iron for less severe cases or blood transfusion for severe cases. Females especially prone to this.
Sickle cell anemia
Hemophilia – inadequate clotting
Mutations in clotting proteins cause profuse bleeding from even minor wounds.
Treat by giving clotting factor. Used to be obtained from blood donors, so many patients contracted HIV and hepatitis. Now use factors produced by bacteria. (Insert human gene into bacteria and have them mass produce the correct protein.)
Clots can form in blood vessels due to internal damage (fatty plaques, for example). If clot obstructs vessels to heart heart attack. Obstruct vessels to brain stroke. Both are debilitating and can be fatal.