What is blood? Connective tissue- yes TISSUE! Cells suspended in plasma matrix
Where are blood cells made? In children, the marrow of most of the bones produces blood. But in adults, only the marrow of certain bones -- the spine, ribs, pelvis, and some others -- continues to make blood. Bone marrow that actively produces blood cells is called red marrow, and bone marrow that no longer produces blood cells is called yellow marrow.
What kind of life span? The different kinds of blood cells have different "life spans" -- red blood cells last about 120 days in the bloodstream; platelets about 10 days; and the various kinds of white blood cells can last anywhere from days to years.
Blood Components: "Blood Count" – % of Each Component
Blood Components: Cells Erythrocytes Red Blood Cells (RBC) O 2 & CO 2 transport White Blood Cells (WBC) Immune defense Phagocytosis Platelets: clotting Liquid part- plasma
Plasma Inorganic salts – dissolved ions called the “blood electrolytes” Plasma is 90% water Some ions buffer the blood to maintain a normal pH of 7.35- 7.45 Salts are important in keeping the correct osmotic balance of blood There are other plasma proteins that play important roles.
Plasma proteins are important! Immunoglobulins= antibodies- fight viruses and other foreign agents that invade Lipid Escort proteins Clotting factors- help form plug when bleed The term “serum” refers to blood after the clotting factors have been removed.
Erthyrocytes Red Blood Cells Most numerous Main function is oxygen transport Structure related to function- AGAIN! Small disks that are biconcave Shape increases surface area Mature RBC do not have NUCLEI! Is this true in all animals? This leaves more space for hemoglobin Made in bone marrow Recycled in spleen
The red blood cells here are normal, happy RBC's. They have a zone of central pallor about 1/3 the size of the RBC. The RBC's demonstrate minimal variation in size (anisocytosis) and shape (poikilocytosis). A few small fuzzy blue platelets are seen. In the center of the field are a band neutrophil on the left and a segmented neutrophil on the right.
There is a basophil in the center of the field which has a lobed nucleus and numerous coarse, dark blue granules in the cytoplasm. They are infrequent in a normal peripheral blood smear, and their significance is uncertain. A band neutrophil is seen on the left, and a large, activated lymphocyte on the right. This is a basophil.
In the center of the field is an eosinophil with a bilobed nucleus and numerous reddish granules in the cytoplasm. Just underneath it is a small lymphocyte. Eosinophils can increase with allergic reactions and with parasitic infestations Eosinophil- bilobed nucleus and red granules
A normal mature lymphocyte is seen on the left compared to a segmented PMN on the right. An RBC is seen to be about 2/3 the size of a normal lymphocyte
Here is a monocyte. It is slightly larger than a lymphocyte and has a folded nucleus. Monocytes can migrate out of the bloodstream and become tissue macrophages under the influence of cytokines. Note the many small smudgy blue platelets between the RBC's. Monocyte Platelet
Blood Components: Platelets Thrombocytes Coagulate, form plug, prevent blood loss Formed by fragmentation from megakaryoctyes
Overview of Hemostasis: Clot Formation & Vessel Repair
Out with the old in with the new! Multipotent- divides one daughter stays stem cell the other becomes specialized Erythrocytes, leukocytes, and platelets form new cells through stem cell division Erythrocytes live only 3-4 months Negative feedback controls erythrocyte production
Negative Feedback… Sensitive to oxygen reaching tissues Controls Erthyrocyte production If low in oxygen then kidneys make and secrete a hormone called erythropoietin ( EPO)that tells the stem cells to make more. If too much oxygen then EPO falls down. Synthetic EPO-treat anemia Athletes- inject EPO- blood doping banned