Exam 1 Review:  Chapter 17:  Formed Elements

formed elements - The membrane-bound "cellular" components of the blood which include the erythrocyte = red blood cells (RBCs), leukocytes = white blood cells (WBCs), and the cytoplasmic fragments of the megakaryocytes referred to as thrombocytes = platelets; all formed elements originate in the red bone marrow.

erythrocyte = red blood cell (RBC) - The cell in the blood which transports oxygen and carbon dioxide to and from the tissues; the mature cell is disk-shaped and biconcave, contains primarily hemoglobin, has little metabolic activity and lacks a nucleus; they have a lifespan of approximately 120 days in circulation.  aka:  red cell, red corpuscle

leukocyte = white blood cell (WBC) - The group of cells (two classes and five or more specific functional types are recognized) in the blood which perform a wide variety of immune defense functions; the various cell types are distinguished by morphology and staining properties as well as by function; they are capable of ameboid movement and can exit the blood stream to move witihin the tissues.  aka:  white cell, white corpuscle

thrombocyte = platelet - A minute, membrane-bound, nonnucleated, disklike cytoplasmic body containing regultory substances which is found in the blood plasma; it is derived from the megakaryocyte of the red bone marrow and it functions in hemostasis to form plugs and to promote blood clotting.

List:

2. The three main functions of blood and describe them by giving specific examples.

          (1)  transport and distribution (delivery of O2, nutrients, regulatory substances; removal of CO2 and metabolic wastes)
          (2)  regulation of internal homeostasis (body temperature, pH, fluid volume, extracellular fluid composition, etc.)
          (3)  protection (contributes to inflammation and repair; prevents blood loss by homeostasis (coagulation); prevents infection and serves other immune defensive roles)

3. The three main types of formed elements and the main components of the plasma. Describe the main function of each.

Formed Element
erythrocyte = RBC
leukocyte = WBC
platelet = thrombocyte

Main Function
O2 transport to tissues; (removal of CO2 and H+ from tissues)
immune defensive functions; (phagocytosis, antibody production, etc.)
hemostasis (coagulation)

Plasma Component
proteins
nutrients
waste products
ions = electrolytes
regulatory substances
respiratory gases

Main Function
transport materials, catalysts, clotting factors, immune molecules, regulatory substances
provide raw materials for growth, repair, and metabolism
none, they are to be eliminated from the body
used in metabolism and regulation of homeostasis
control a wide variety of physiological processes
necessary for aerobic metabolism and acid-base balance