• Recognize and use terms related to the anatomy and physiology of the blood, lymphatic, and immune systems. • Recognize and use terms related to the pathology of the blood, lymphatic, and immune systems. • Recognize and use terms related to the diagnostic procedures for the blood, lymphatic, and immune systems. • Recognize and use terms related to the therapeutic interventions for the blood, lymphatic, and immune systems. • Transportation of gases (oxygen [O2] and carbon dioxide [CO2]), chemical substances (hormones, nutrients, salts), and cells that defend the body. • Regulation of the body’s fluid and electrolyte balance, acid-base balance, and body temperature. • Protection of the body from infection. • Protection of the body from loss of blood by the action of clotting. The lymphatic system is responsible for the following: • Cleansing the cellular environment. • Returning proteins and tissue fluids to the blood (drainage). • Providing a pathway for the absorption of fats and fat-soluble vitamins into the bloodstream. The immune system is responsible for the following: Fig. 9-1 is a Venn diagram of the interrelationship among the three systems, with the shared goals of homeostasis and protection at the intersection of the three circles. Fig. 9-2 shows the relationship of the lymphatic vessels to the circulatory system. Note the close relationship between the distribution of the lymphatic vessels and the venous blood vessels. Tissue fluid is drained by the lymphatic capillaries and is transported by a series of larger lymphatic vessels toward the heart. The hematic system is composed of blood and the vessels that carry the blood throughout the body. The process of blood formation is called hematopoiesis (hee mah toh poy EE sis). All blood cells originate from a single type of cell called a stem cell. Because blood can be an extremely important part of the diagnostic process, students need to understand its normal composition. Blood is composed of a solid portion that consists of formed elements, or cells, and a liquid portion called plasma (PLAZ muh). Blood cells make up 45% of the total blood volume, and plasma makes up the other 55% (Fig. 9-3). The solid portion of blood is composed of three different types of cells: 1. Erythrocytes (eh RITH roh sites), also called red blood cells (RBCs). 2. Leukocytes (LOO koh sites), also called white blood cells (WBCs). 3. Thrombocytes (THROM boh sites), also called clotting cells, cell fragments, or platelets (PLATE lets). Hgb, HB, Hb, and HG are all abbreviations for hemoglobin. Hg is the abbreviation for mercury. The erythrocytes (which are normally present in the millions) have the important function of transporting O2 and CO2 throughout the body (Fig. 9-4). The vehicle for this transportation is a protein-iron pigment called hemoglobin (HEE moh gloh bin). 1. Eosinophils (ee ah SIN oh fils) (eosinos) are cells that absorb an acidic dye, which causes them to appear reddish. An increase in eosinophils is a response to a need for their function in defending the body against allergens and parasites. 2. Neutrophils (NOO troh fils) (neuts) are cells that absorb neither an acidic nor a basic dye and consequently are a purplish color. They are also called phagocytes (FAG oh sites) because they specialize in phagocytosis (fag oh sye TOH sis) and generally combat bacteria in pyogenic infections. This means that these cells are drawn to the site of a pathogenic “invasion,” where they consume the enemy and remove the debris resulting from the battle. 3. Basophils (BAY soh fils) are cells that absorb a basic (or alkaline) dye and stain a bluish color. Especially effective in combatting parasites, they release histamine (a substance that initiates an inflammatory response) and heparin (an anticoagulant [an tee koh AGG yoo lunt]), both of which are instrumental in healing damaged tissue. 1. Monocytes (MON oh sites): These cells, named for their single, large nucleus, transform into macrophages (MACK roh fay jehs), which eat pathogens (phagocytosis) and are effective against severe infections. 2. Lymphocytes (LIM foh sites) (lymphs): These cells are key in what is called the immune response, which involves the “recognition” of dangerous, foreign (viral) substances, and the manufacture of their neutralizers. The foreign substances are called antigens (AN tih juns), and the neutralizers are called antibodies (AN tih bod ees). Platelets (also known as thrombocytes) have a round or oval shape and are so named because they look like small plates. Platelets aid in coagulation (koh agg yoo LAY shun), the process of changing a liquid to a solid. When blood cells escape their normal vessels, they agglutinate (ah GLOO tih nate), or clump together, by the following process: First, they activate clotting factors (such as Factor X) that produce prothrombin activator (PTA). Next, in the presence of calcium, the PTA reacts with the blood protein, prothrombin (proh THROM bin), to form thrombin. Thrombin then converts another blood protein, fibrinogen (fye BRIN ah jen), to fibrin (FYE brin), which eventually forms a meshlike fibrin clot (blood clot), achieving hemostasis (hee moh STAY sis) (control of blood flow; that is, stopping the bleeding). See Fig. 9-5 for a visual explanation of the clotting process. Plasma, the liquid portion of blood, is composed of the following: 2. Inorganic substances (calcium, potassium, sodium) 3. Organic substances (glucose, amino acids, fats, cholesterol, hormones) 4. Waste products (urea, uric acid, ammonia, creatinine) 5. Plasma proteins (serum albumin, serum globulin, and two clotting proteins: fibrinogen and prothrombin) Human blood is divided into four major different types: A, B, AB, and O. See Fig. 9-6 for a table of blood types, agglutinogens, and agglutinins. The differences are due to antigens present on the surface of the red blood cells. Antigens (ANN tih jens) are substances that produce an immune reaction by their nature of being perceived as foreign to the body. In response, the body produces substances called antibodies that nullify or neutralize the antigens. In blood, these antigens are called agglutinogens (ah gloo TIN oh jens) because their presence can cause the blood to clump. The antibody is termed an agglutinin (ah GLOO tin nin). For example, type A blood has A antigen, type B has B antigen, type AB has both A and B antigens, and type O has neither A nor B antigens. If an individual with type A blood is transfused with type B blood, the A antigens will form anti-B antibodies because they perceive B blood as being foreign. Following the logic of each of these antigen-antibody reactions, an individual with type AB blood is a universal recipient, and an individual with type O blood is a universal donor. 1. The four blood types are _________________________________________________________. 2. Blood types are different because of ________________________________________ on the surface of the red blood cells. 3. A person with type A blood can donate blood to people with which blood type? _________________________________________________________ 4. Type O blood type is the (universal donor, universal recipient), whereas type AB is the (universal donor, universal recipient) (underline one). 5. HDN is an example of an antigen-antibody reaction of what blood factor? _________________________________________________________ The lymphatic system is responsible for the following: • Cleansing the cellular environment • Returning proteins and tissue fluids to the blood • Providing a pathway for the absorption of fats into the bloodstream The lymphatic system (Fig. 9-7) is composed of lymph (or interstitial fluid), lymph vessels, lymph nodes or lymph glands, lymph organs (e.g., tonsils, adenoids, appendix, spleen, thymus gland, patches of tissue in the intestines called Peyer’s patches), and lymphoid tissue. Monocytes and lymphocytes pass from the bloodstream through the blood capillary walls into the spaces between the cells in body tissue. When they pass into this lymph or interstitial fluid that surrounds cells, they perform their protective functions. Monocytes change into macrophages (MACK roh fay jehs), destroy pathogens, and collect debris from damaged cells. Lymphocytes are much more complicated and are essential to the immune response, so they are discussed in the next section. Once monocytes and lymphocytes pass into the lymphatic capillaries, the fluid is termed lymph or lymphatic fluid. 1. From the interstitial spaces between the cells, then 2. Toward the heart through lymphatic capillaries. 3. To lymphatic vessels that carry lymph via valves (one-way vessels). 4. To the lymphatic nodes, which are also called lymph glands, that filter the debris produced by macrophages. These nodes can become enlarged when pathogens are present. Note the major lymph nodes in Fig. 9-7, including the cervical, axillary, inguinal, and mediastinal nodes. 5. Then to either the right lymphatic duct or the thoracic duct, both of which empty into the large subclavian veins in the neck. 6. Once in the venous blood, the lymph is recycled through the body through the circulatory system. Fig. 9-8 illustrates the levels of defense. The two outside circles represent nonspecific immunity and its two levels of defense. The inner circle represents the various mechanisms of specific immunity, which can be natural (genetic) or acquired in four different ways. Most pathogens can be contained by the first two lines of nonspecific defense. However, some pathogens deserve a “special” means of protection, which is discussed under “Specific Immunity.”
Blood, Lymphatic, and Immune Systems
Functions of the Blood, Lymphatic, and Immune Systems
Anatomy and Physiology
Hematic System
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Components of Blood
Erythrocytes (Red Blood Cells)
Leukocytes (White Blood Cells)
Granulocytes (Polymorphonucleocytes)
Agranulocytes (Mononuclear Leukocytes)
Thrombocytes (Platelets [plats])
Plasma
Blood Groups
Exercise 2: Blood Groups
Lymphatic System
Immune System
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Exercise 1:
You can review the anatomy of the lymphatic systems by clicking on Body Spectrum Electronic Anatomy Coloring Book → Lymphatic.
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Exercise 3:
Exercise 4:
