Unit 1. Case Study 1. Tell Me About Blood
1. What is the significance of a lower-than-normal hematocrit? What is the effect of a bacterial infection on the hematocrit? (PAGE 618 619)
First, hematocrit (HCT) is the percentage of blood made up of red blood cells. Usually measured by centrifuging a blood sample in a graduated tube and then reading the volume of red blood cells and dividing it by the total volume of blood in a sample. A significant drop in hematocrit is an indication of anemia (lower-than-normal number of red blood cells (Jenkins & Tortora, 2013). A bacterial infection would increase the production of white blood cells to fight off the infection. The hematocrit would have a thicker buffer layer (white blood cells) causing the red blood cell production to slightly decrease which would decrease the ratio of red blood cells to whole blood volume.
2. Compare the development of lymphocytes with the development of the other formed elements. (PAGES 629 631 632 769)
Lymphocytes and the other formed elements are developed from pluripotent stem cells. The pluripotent stem cells generate myeloid stem cells and lymphoid stem cells. Myeloid stem cells start and complete their development in red bone marrow and give rise to red blood cells, platelets, eosinophils, basophils, neutrophils, and monocytes. Lymphoid stem cells begin development in the red bone marrow, but some are completed in the lymphatic tissues, where they give rise to lymphocytes. The B cell lymphocytes begin and finished in the red bone marrow and the T cell lymphocytes begin in the red bone marrow, but they mature in the thymus (Jenkins & Tortora, 2013).

3. What is erythropoiesis? Which factors speed up and slow down erythropoiesis? (PAGES 624-625)
Erythropoiesis is the specific production of red blood cells or erythrocytes. It starts in the red bone marrow with a precursor cell called a proerythroblast. The proerythroblast divides many times and produces cells that begin to make hemoglobin. A cell near the end of the development cycle ejects its nucleus and then becomes a reticulocyte. Reticulocytes pass from red bone marrow into the bloodstream. The lack of oxygen or blood flow can slow erythropoiesis. Cellular oxygen deficiency is called hypoxia and may occur in lower oxygen content of air at high altitude and also may occur due to anemia. (Jenkins & Tortora, 2013).
4. Explain what would happen if a person with type B blood were given a transfusion of type O blood. (PAGES 627-628)
Nothing would happen, O is compatible. Type O+ blood is considered the universal donor and type AB+ is considered the universal recipient. In the body, every cell has a blood type; antigen (A, B, AB, O) and antibody Rh factor (+,-) that relate to the immune system. If another blood cell type is introduced into the blood stream, the immune system will consider it as an invading cell and work to destroy it. The reaction is an acute hemolytic response; meaning the cells are lysed (destroyed) causing their byproduct to enter the blood stream. The compliment system is activated causing clotting within the circulatory system. These clots find their way into capillary beds in the lungs, liver, heart, tissue etc. and cause a massive ischemic (lack of oxygen) event. This is irreversible and ultimately fatal. O+ is the universal donor to Rh+ recipients because O type blood lacks both A and B antigen. The immune system of the recipient checks out the new blood and finds nothing wrong with it as only antigenic sequences can spur an immune response. (Jenkins & Tortora, 2013).

5. During an anatomy and physiology exam you are asked to view white blood cells in prepared slides of standard human blood smears. Based on the observations below, what is the name and function of each WBC? (PAGE 632) (Jenkins & Tortora, 2013).
a. WBC has a round nucleus surrounded by a blue halo of cytoplasm with no visible granules.
Lymphocytes (T cells, B cells, and natural killer cells) –