Chapter 6 Flashcards
What are the three functions of blood?
Transport - Blood is the primary transport medium of the body. Blood transports gases and nutrients and carries away wastes from all parts of the body. Hormones are also transported in the blood.
Defense - Blood defends the body against pathogen invasion and blood loss.
Regulation - Blood has regulatory functions for temperature, water-salt balance, and pH.
What are the two components of blood? Name the cellular components found in the blood. What are pluripotent stem cells?
Blood is a tissue that contains cells and cell fragments suspended in a liquid called plasma.
The formed elements are: red blood cells, white blood cells, and platelets.
Red blood cells are two to three times smaller than white blood cells, but there are many more of them.
Pluripotent stem cells in red bone marrow give rise to the different types of blood cells and may have the potential to treat human diseases.
What types of components are found in blood plasma? Describe the functions of the following: albumins, globulins, gamma globulins, fibrinogen.
Plasma is the liquid portion of blood. It’s mostly made up of water, but it also contains salts, small organic molecules, hormones, and plasma proteins.
The liver makes most plasma proteins that function to buffer the blood, transport molecules, and maintain osmotic pressure. Each protein also has specific functions.
Albumins contribute most to plasma’s osmotic pressure, and they help transport other organic molecules.
Globulins include alpha and beta globulins, which also help transport substances in the blood, and gamma globulins, which are the antibodies of immunity.
Fibrinogen is involved in blood clotting.
Describe the structure of a red blood cell (erythrocyte).
Red blood cells (erythrocytes) are small, biconcave disks that lack a nucleus when mature. There are 4 to 6 million red blood cells per microliter of whole blood.
What substance carries the oxygen in red blood cells?
Red blood cells contain hemoglobin, the respiratory pigment that transports oxygen.
How is carbon dioxide transported in the blood?
Hemoglobin directly transports about 23% of carbon dioxide, which binds to the terminal amino groups of the globin molecules.
The remaining carbon dioxide is transported as the bicarbonate ion in the plasma. When blood containing bicarbonate ions reaches the lungs, carbon dioxide diffuses out of the blood into the lungs and is exhaled. The enzyme carbonic anhydrase, contained in red blood cells, catalyzes the reaction of carbon dioxide and water to form carbonic acid
Where are blood cells produced? What is the average life span of a red blood cell? What is EPO?
Red blood cells are produced in the bone marrow. Red blood cells live only about 120 days and are destroyed in the liver and the spleen. Hemoglobin is released when blood cells are broken down. Iron is recovered and recycled to the bone marrow. Pigments from hemoglobin are excreted as bile pigments. The kidneys release the erythropoietin hormone (EPO), which stimulates bone marrow stem cells to make more red blood cells.
Describe the following disorders involving red blood cells: anemia, sickle-cell disease.
Anemia results from too few red blood cells and/or insufficient hemoglobin.
Sickle-cell disease is a hereditary condition in which the hemoglobin molecule is abnormal and the individual has sickle-shaped red blood cells that tend to rupture as they pass through the narrow capillaries.
Describe the structure of white blood cells (leukocytes). What are their functions?
White blood cells (leukocytes) are large and nucleated, and they function in immunity. They squeeze through capillaries and invade tissues when needed. Some white blood cells are very good at phagocytosis, while others produce antibodies.
What are colony-stimulating factors?
Colony-stimulating factors (CSFs) are proteins that regulate the production of white blood cells. The immune system defends the body against pathogens, cancer cells, and foreign proteins.
What is an antigen?
An antigen is a cell or other foreign substance that provokes an immune response.
What are the functions of the following granular leukocytes: neutrophils, eosinophils, basophils.
Neutrophils (or polymorphonuclear leukocytes) engulf bacteria and debris through phagocytosis.
Eosinophils are numerous during allergic reactions or parasitic infections.
Basophils and similar cells called mast cells release histamine associated with allergic reactions.
What are the functions of the following agranular leukocytes: monocytes, lymphocytes
Agranular leukocytes include monocytes, which become macrophages that phagocytize pathogens and cellular debris in tissues, and lymphocytes (B cells and T cells), which are responsible for specific immunity to particular pathogens and toxins.
Briefly describe the following disorders of white blood cells: severe combined immunodeficiency (SCID), leukemia, mononucleosis.
Inherited immune deficiencies such as severe combined immunodeficiency (SCID) result from disorders with the production and/or function of white blood cells. Cancer of white blood cells is called leukemia. Infectious mononucleosis, one of the most common human viruses, is a disease in which a virus infects lymphocytes.
Describe the structure and function of platelets (thrombocytes).
Platelets (thrombocytes) result from the fragmentation of megakaryocytes in the red bone marrow. These are involved in the process of blood clotting.
