Ch 23 Hematologic and Lymphatic

Blood Groups and Compatibilities

Blood Group A -Antigen A on erythrocytes -Anti-B antibody in plasma( reacts against A antigen) -Can donate RBCs to: A or AB -Can receive RBCs from: A or O Blood Group B -Antigen B on erythrocytes -Anti-A antibody in plasma( reacts against A antigen) -Can donate RBCs to: B or AB -Can receive RBCs from: B or O Blood Group AB "universal recipient" -Antigen A and B on erythrocytes -No antibody in plasma -Can donate RBCs to: AB -Can receive RBCs from: A, B, AB, or O Blood Group O -No Antigens on erythrocytes -Anti-A and Anti-B antibody in plasma( reacts against both A and B factors) -Can donate RBCs to: A, B, AB, or O -Can receive RBCs from: O

Cerebral circulation

The circle of Willis (cerebral arterial circle) is formed by the anterior communicating artery, posterior communicating artery, anterior cerebral artery, posterior cerebral artery, and internal carotid artery. -Cerebral blood flowIs 10-15% of total cardiac output. Requires Continuous blood flow because it requires constant supply of oxygen and nutrients (specifically glucose) to survive. Does not have ability to create collateral circulation. -Mean arterial blood pressure (MAPB) is calculated based on relationship between systolic and diastolic. -Circle of Willis is important because it allows blood to continue to flow in the brain if one of the arteries supplying the brain is blocked. -Middle cerebral artery branch most likely location for emboli.

Lymph

The lymphatic system also functions as part of the body's immune system and is sometimes referred to as the secondary circulatory system. As lymph passes through the specialize lymphoid tissue (that is densely packed with lymphocytes and some other WBCs, enmeshed in connective tissue) damaged cells and waste materials are filtered out. -The primary lymphatic system consists of the thymus gland and bone marrow involved in production and early selection of lymphocytes -The secondary lymphatic system consists of encapsulated tissue (the spleen and lymph nodes, covered with connective tissue) and nonencapsulated tissue )intestinal lymphoid tissue and tonsils.) Functions: -Immune response—defense against infection and prevention of metastasis of malignancies -Removal of excess ISF from tissues -Absorption and transport of fatty acids and fats )as chyle) to the circulatory system -Transports of antigen-presenting cells (APC) such as Dendrid excels the lymph nodes to activate an immune response

Normal Lab Values *Hemoglobin *RBC *leukocytes *Platelets

*Hemoglobin F: 14-18g/DL M: 12-16. Infant: 16.5-19.5 *RBC F: 4.6-6.2 million/mm3 M: 4.2-5.4 *leukocytes: 5,000-9,000 - band neutrophils: 3-5 - segmented neutrophils: 54-62 - lymphocytes: 25-33 - monocytes: 3-7 - eosinophils: 1-3 - basophils: 0-1 *Platelets: 150,000-400,000/mm3

Granular leukocytes (granulocytes)

-Also called polymorphonuclear leukocytes (PMNs) or segmented neutrophils (segs) because their nuclei have so many lobes or the lobes are so divided as to look like more than one nucleus. -In granulocytes, membrane bound enzymes aid in digestion of foreign particles in a process called endocytosis. -Granulocyte are divided into three sub groups: neutrophils, eosinophils and basophils. *Neutrophils -Most numerous WBCs (50-75%) are phagocytes. Most commonly called PMNs. Because they are segmented, containing multiple lobes, they are also called segs. -Colorless unless stain. Considered to be first line of defense against bacteria and also defend against fungi, in some measure. -Neutrophils can move away from blood vessels and travel directly to the site of infection or damage tissues because of their attraction to specific chemicals (chemotaxis) -The term "endocytosis" involves both phagocytosis (engulfing of particulate matter) and Pinocytosis (engulfing of extracellular fluid materials) -Increase in number during bacterial infection, burns, or inflammation. Short lifespan of 10 hours, need to be replaced frequently. When infection occurs more neutrophils are released from bone marrow, when demand is very high bone marrow releases immature neutrophils called "bands" Increase number of bands signifies an infection referred to as a "shift to the left" **Eosinophils -0.3-7% of circulating WBC. Characterized by Speckled or grainy cytoplasm, survive only about 12 hours- 3 days -Increase in number during allergic reactions and parasitic infections, believed to release chemicals to assist body in detoxifying foreign proteins or engulfing and devouring invaders including antigen and antibodies. -Able to squeeze through capillary walls and usually respond to allergens. They collect and loose connective tissue and may also have a role in decreasing the release of chemical mediators during allergic reactions **Basophils -Not phagocytes, less than 2% of WBCs, involved in allergic and inflammatory reaction. -Contain heparin and releases histamine in response to Inflammation or another immune stimulus. Histamine increases permeability of blood vessels, along with other substance, acts on foreign invaders in the body causing a hypersensitivity reaction resulting in vasodilation and edema, itching, and possibly bronchial constriction, and allergic or inflammatory response

Formed elements: White blood cells

-Also known as leukocytes, about 1% of blood volume in healthy adult, do not contain hemoglobin. -Leukocytes are derived from the cell in the bone marrow, the hematopoietic stem cell. -Located in both of blood and lymphatic system. Defend against disease organisms, toxins, irritants, and other foreign materials. Also assist in repairing damage tissues, sometimes dying during this activity and collect with bacteria form pus. -Larger than RBC, contain nuclei, and can move independently. -Two main types of WBC are granular and agranular.

Formed Elements: RBC

-Erythrocytes or red corpuscles, flattened, biconcave discs. Most abundant, 25 trillion -When mature, no nucleus present(therefore no DNA, so RNA cannot be synthesized). Cannot reproduce or synthesize protein. -Consists mostly of hemoglobin, in surround medium, the stroma. Made of stem cells in red bone marrow, mostly in large bones. Macrophages in liver and spleen ingest old, used RBCs and salvage iron, which is transported to bone marrow to make new RBCs. -Lifetime: 120 days, Every second 2+ million RBCs die and are replaced. Body manufactures about 120-180 million RBCs every minute. -Erythropoiesis begins in kidney cells stimulated by decreased oxygen levels to release the hormone erythropoietin which stimulates red bone marrow to produce RBCs -Hemoglobin is composed of the iron-containing pigment "heme" and a protein "globin". Iron is the pigment that makes RBCs appear red. Hemoglobin allows blood to carry 60 times more oxygen than would plasma. -Some RBCs may be stored in the spleen and dumped into the blood during exertion or stress, increasing the oxygen carrying capacity of blood. Functions of RBCs -If RBCs experience stress because blood vessels are constructed they release adenosine triphosphate (ATP) which causes vessel walls to relax and dilate -RBCs also produce ATP (energy carrier) by fermentation -When hemoglobin is deoxygenated, RBCs release substances which assist in dilation of blood vessels and facilitate blood flow to oxygen poor areas -RBCs store iron in the body; RBCs themselves are stored in the spleen -RBC are involved in the immune response. If they are lysed by pathogens the hemoglobin releases free radicals that break down cell walls of the pathogens. -Myoglobin a compound related to hemoglobin stores oxygen in muscle cells -RBCs are important and acid-base balance and have an influence on specific gravity of blood because they contribute viscosity (thickness) to the blood. KEY CONCEPT: Iron in hemoglobin picks up oxygen in the lungs that is exchanged for carbon dioxide at the cellular level which is return to the lungs in plasma, to complete the cycle. RBCs do not use any of the oxygen they transport. The average female has fewer RBCs than male. A deficiency of RBC is one form of anemia. During inflammation RBCs may stack up due to elevation of specific proteins (a rouleaux formation). People living in high altitude have more RBCs because each RBC carries less oxygen. RBC must be in an isotonic solution to survive

Lymphatic Circulation

-Lymph only carries fluid it away from tissues -The lymph from the upper right quadrant of the body drains into the right lymphatic duct. The remainder of the lymph drains into the left lymphatic duct (commonly known as a thoracic duct), both draining into the left subclavian vein at the base of the neck, where lymph mixes with blood plasma and becomes part of the general circulation -Lymph enters lymph nodes through several afferent "towards" and lymph vessels. Lymph nodes filter out dangerous substance (cancer cells and bacteria), dead RBCs and foreign matter (smoke by-products) that become trapped in nodes. The lymph then continues to flow away from the node through one or two efferent "taking away" lymph vessels into the bloodstream -Plasma cells and lymphocytes that have reproduced within a lymph node can also be added to them for transportation to blood

Hepatic Portal Circulation

-Subdivision of systemic circulation. It is an efficient detour in venous return, directed at transporting raw materials (carbohydrates, fats, and proteins) from the digestive organs and spleen to liver -Unique because it begins and ends with capillaries. Capillaries from the stomach, intestines, spleen, and pancreas empty into veins that drain into a common vessel, the portal vein, which leads into the liver. -In the liver, blood again enters capillaries, called sinusoids. Here the liver extracts appropriate materials and chemically modifies them. -The liver synthesizes, stores, detoxifies, regulate, and transforms these raw materials into useful material to meet body needs. Useful substance and blood Then empty into the hepatic vein, which leads to the inferior vena cava

Blood

-Versatile vascular fluid, heavier, thicker, and more viscous than water. Although it is liquid, unique qualities allow it to form solid clots. -Primary purpose is to maintain constant environment for all body tissues. Maintain homeostasis via its viscosity, and by its ability to carry dissolved substances to all body parts. -Responsible for transportation of O2, CO2, nutrients, heat, waste products, disease-fighting substances, and hormones to and from cells. Also helps regulated pH, body temp, and cellular water content. Contributes to protection from blood loss and foreign invasion. -Considered a connective tissue in terms of origin and development, but differs from other connective tissue because it's cells are not fixed and moved freely to all body cells -Hematopoiesis (hemopoiesis): production, multiplication, maturation, and specialized of blood cells in the bone marrow. (In embryo, RBC produced in the liver and spleen -Erythropoiesis; formation of RBC. Glycoprotein-type hormone, erythropoietin, is secretes by the kidneys in adults, stimulating stems cells in bone marrow to produce RBCs. >Dietary elements (iron, cobalt, amino acids, and certain vitamins also required for erythropoiesis. Bone marrow releases immature RBCs (reticulocytes) which mature in about a day -Composed of both plasma and formed elements. Carried through a closed system of vessels pumped by the heart. KEY CONCEPT; A form of erythropoietin may be used to treat anemia caused by insufficient or ineffective RBCs. Called recombinant human erythropoietin (RHE) or epoetin alfa.

Blood Brain Barrier

An adaptation of the circulation that protects the brain. -Specialize cells in brain capillaries allow only certain substance from blood to enter the brain. -Capillaries in the brain are less permeable and much tighter than other capillaries in the body, thus limiting what substance are admitted into the cerebral circulation and to bring tissue. -Also specialized brain neuroglia, astrocytes, assist in creating selective permeability in the brain. The Circle of Willis helps provide uninterrupted blood supply to the brain. The blood brain barrier protects the brain from harmful substances.

Blood groups and RH factor

Blood does not carry or transmit mental, emotional, or physical characteristics. Human blood falls into one of four (inherited) genetic groups (blood types): A, B, AB, and O. Just as with a blood group, Rh factors are inherited antigens. (System is named after the rhesus monkey used in early experiment) -Most commonly found Rh factor and the one most likely to cause a transfusion reaction is abbreviated D (Duffy). Blood is tested for the presence of the D antigen, if blood contains it, person is said to be RH-positive (Rh+ or D+), if absent in blood person is Rh-negative (Rh-) -When an Rh- person receives Rh+ blood, they develop antibodies that could cause a severe reaction to subsequent blood transfusions. This can also occur within positive pregnancy Rh-negative mother.

Plasma and plasma proteins

Blood plasma, fluid portion of circulating blood, 55% of blood volume and 90% water. Remaining 10% consists primarily of plasma proteins, also includes salts (electrolytes), nutrients, nitrogenous waste products, gases, hormones, and enzymes. -Plasma absorbs salts from foods for use by cells. Maintenance of these salts within the plasma controls the chemical and acid-base balance of blood and contributed to homeostasis. -Salts in plasma; sodium, potassium, calcium, and magnesium. Also contains ions of other elements (bicarbonates, sulfates, chlorides, and phosphates) *Plasma Proteins: 4 groups manufactured in liver -Albumin; largest group, 60-80% of plasma proteins. Important function is to provide thickness to circulating blood volume maintaining osmotic pressure. (Draws water from surrounding tissue fluid into capillaries and thus maintains fluid volume and BP). Loss of albumin can result in dramatic fluid shifts, edema, hypotension, and even death. *KEY CONCEPT: Albumin helps maintain BP and circulating fluid volume. -Fibrinogen + prothrombin; essential for clotting -Globulin; two types of globulin (alpha and beta) are formulated in liver and acts as carriers for molecules, such as fats. *Gamma globulins (immunoglobulins [Ig]) are antibodies, materials synthesized by body in response to antigens (foreign invaders), thus providing immunity against infection and disease.

Hemorrhage

Escape of blood from blood vessels, usually thought of as the loss of considerable amount of blood after injury. -Hemostatic mechanisms, such as clotting, help prevent hemorrhage in smaller vessels, but extensive hemorrhage from larger vessels requires medical intervention. -Inability to clot in extensive hemorrhage may be caused by several factors; force of blood flow, size of wound, volume of blood loss, or deficiency in any of the coagulant components. KEYCONCEPT: Often more blood is lost from a torn or nicked blood vessel than from a vessel that is cleanly cut through. The muscles in a blood vessel contract as a protective measure. If the muscles are cut on evenly they cannot effectively close the vessel. *Hemorrhage from an artery comes in spurts hemorrhage from a vein in a steady flow.* Hemophilia, a medical condition in which the blood clotting ability is severely reduced, causes the person to bleed severely from even a slight wound.

Hematologic System

Hematologic system consists of blood (plasma and formed elements) and bone marrow (primary organ that manufactures blood cells). Functions; -Transportation, regulation and protection. These functions involve delivery of nutrients and oxygen, as well as immune substances and hormones to the cells. This system also removes wastes, and regulates blood volume, blood cell and antibody production, and blood coagulation. *Transportation - Transports oxygen to body cells and carbon dioxide away from body cells - Exchanges oxygen for carbon dioxide at cellular level - Transports water, nutrients, and other needed substances, such as salt (electrolytes) and vitamins, to body cells - Aids in body heat - Transport water products from cells to be removed from circulation (ex: kidney removes excess water, electrolytes, and urea; liver removes bile pigments and drugs; lungs remove carbon dioxide -Transports hormones from sites of origin to organs they affect - Transports enzymes *Regulation - Contributes to regulation of body temperature - Assists in maintenance of acid-base balance - Assists in maintenance of fluid-electrolyte balance *Protection - Fights disease and infection(leukocytes) - Promotes clotting of blood (platelets and specializes factors) - Provides immunity due to antibodies and antitoxins (specialized cells)

Blood clotting

Hemostasis refers to cessation of bleeding. When blood vessels are damaged or ruptured, the hemostatic response must be quick and carefully controlled, to stop excessive blood loss. Initial response includes vascular spasm (vasoconstriction), platelet plug formation, and blood clotting (the coagulation process that forms of fibrin clot) -Clotting protects the body from losing vital plasma and blood cells by sealing off broken blood vessels. -Coagulation is a complicated mechanism that cannot occur if any necessary elements are missing. Vitamin K is necessary for the formation of prothrombin and other clotting factors. (Bacteria in the colon produce most vitamin K) -A thrombus is a stationary clot. An embolus is a clot that circulates. Both can lead to death if they plug arteries. KEY CONCEPT: The initial response to disruption in a blood vessel includes vascular spasm (vasospasm), platelet plug formation, and the coagulation process that forms a fibrin clot. Platelets, calcium iron's, and vitamin K are important elements in this complex coagulation process. A scab is the evidence of a fibrin clot.

Lymph nodes and nodules

Lymph nodes are small bundles of special lymphoid tissue situated in clusters along the lymphatic vessels -Many lymph node appear in the neck (cervical), groin (inguinal), and armpits (axillary) -Consist of three layers and is encapsulated in a fibrous capsule. >Outer area, the superficial cortex, contains lymphoid follicle >Deep cortex and interfollicular Areas contain mostly T cells >Inner portion, the medulla, is made up of plasma cells which secrete immune globulins. -Area calmed "hilum" provides a portal for efferent lymph vessels and for arteries and veins. Functions of lump nodes: -Most important is filtering out and destroying pathogens. "Swollen glands" are lymph nodes at work. Nodes have enlarged as their macrophages eat and destroy invaders. enlarged non-malignant nodes are soft and tender and may become painful -Lymph nodules, small masses of nonencapsulated lymphatic tissues, standard in all mucous membranes. Strategic location to filter substance that enter the body *If cancer is found in lymph nodes it is said to be spreading or metastasizing. If no cancer cells are present in adjoining lymph nodes, the cancer was almost like the localized to each original site. Palpable cancerous lymph nodes may be enlarged and, unlike nodes fighting infection, feel firm and nontender.

Formation and movement of lymph

Normally body cells are bathe in tissue fluid, some of which drains into blood capillaries and flows directly into veins. Lymphatic vessels also drain this fluid. -The lymphatic vessels begins as a network of tiny closed-ended lymphatic capillaries, slightly larger than blood capillaries, in spaces between cells. -Unique structure allows ISF to flow into them but not out. 10-20% of bodies ISF enters lymph capillaries. -As ISF comes into contact with blood, it accumulates more lymphocytes, other cells, proteins and certain waste products. When ISF enters lymphatic conduits, it becomes the thin, watery, colorless liquid known as lymph. -Because lymph originally derives from plasma, it's composition is much the same, except that lymph is lower in protein content. (specialized lymphatic capillaries, lacteals, absorb digested fat and fat soluble vitamins in the small intestines) Lymphatic vessels contain one way semilunar valve that prevent backflow of lymphatic fluid into the ISF. Lymphatic vessels are located both superficially and deeper in the body. Most lymphatic vessels are located near the venous system and are named accordingly. -Lymphatic vessels carrying fluid eventually form a network of vessels in specific areas of the body, regional nodes. -After fluid moves through the node, it is transported by other lymphatic vessels to either the right lymphatic duct or the thoracic duct -Lymphatic fluid is propelled through the body by rhythmic contractions which occur due to changes in abdominal and thoracic pressure during breathing and because of skeletal muscle contractions. Pulsation of arteries also aids in movement of lymph. All of these promote the return of venous blood and subsequently lymphatic fluid to the heart

Formed elements: Platelets

Platelets, thrombocytes, exist in the billions and are form in red bone marrow by megakaryocytes. -Smallest formed elements in the blood and are essential in blood clotting. -They stimulate contractions of injured blood vessels and also form a hemostatic plug, to stop or slow bleeding by clumping of many platelets together (aggregation) -Also combine with plasma to speed blood coagulation -Not whole cells, but rather fragments of larger cells. They lack nuclei, but are capable of ameboid movement.

Lymphatic System

The lymphatic system consists of the lymphatic vessels and tissues, and lymph. Other organs and structures, such as spleen, liver, and kidneys, also perform specific related functions. Functions: -Transports dietary fats, drains interstitial fluid (ISF), and provides immunity against infection. it also recycles and returns excess proteins that may escape from blood vessels back into the systemic circulation. *Transportation -Carries fluid away from tissues -Carries wastes away from tissues *Absorption - Absorbs fats and transports fats to blood (lacteals) - Stores blood (spleen) - Destroys worn-out erythrocytes *Protection -Filters wastes products out of blood -Filters foreign substances out of blood (including dead blood cells, bacteria, smoke by-products, cancer cells) -Destroys bacteria -Participates in antibody production to fight foreign invasion *Manufacture -Manufactures lymphocytes and monocytes -Manufactures erythrocytes (spleen in fetus)

Agranular leukocytes (agranulocytes)

The nuclei of these WBCs do not contain lobes. Under normal conditions, agranular leukocytes are functionable for about 100-300 days. They are produced in the lymphatic tissue of the spleen, lymph nodes, and thymus, and in hemopoietic tissues in red bone marrow. Two subgroups; lymphocytes and monocytes. **Lymphocytes -Smallest and most numerous of agranular WBCs (20-43%). They mature in bone marrow and can be differentiated into several types. The most important types are B-lymphocytes (B-cells) and T-lymphocytes (T-cells) -B-cells make antibodies that bind to pathogens so they can be destroyed -T-cells are of several types. CD4, or "T-helper cells", coordinate the immune response. CD8 cells are cytotoxic (cell destroying) and can kill viruses, infected cells, and tumor cells. -Natural killer cells can kill special cells which are displaying our unique signal (After having been invaded by a virus or becoming cancerous) -The B- and T-lymphocytes play in important role in the immune response. lymphocyte increase in number during infectious process, particularly those caused by viral infections are immune disorders **Monocytes -Largest WBC, characterized by absence of granules in cytoplasm, except for lysosomes. 1-9% of WBC and play a role in acute and chronic inflammation processes. -Move from bloodstream to other tissues were they are transformed into macrophages or dendritic cells (histiocytes) (Dendritic cells function to activate T-lymphocytes) -Monocytes also clean up after phagocytosis by ingesting cellular debris and dead tissue, as well as presenting fragments of pathogens to the T-cells so they can be killed or form antibodies. -A high monocyte count may be caused by a viral or fungal infection, tuberculosis, or certain chronic diseases. **Macrophages -Phagocytic cells, as are neutrophils. -Collect in body structures such as the spleen, liver, and lymph nodes, where large amounts of fluids are processed. Here, they defend against invading microorganisms and promote wound healing. They engulf and digest cellular debris and pathogens after phagocytosis. They also stimulate lymphocytes and other immune cells to function. Key concept: RBC: 120 days Neutrophils: 10 hours Eosinophils: 12 hours-3 days Monocytes and Lymphocytes: 100-300 days

Lymphatic Organs -Tonsils -Spleen -Thymus

These organs are masses of lymphatic tissue with somewhat different functions than those of lymph vessels or nodes. The tonsils and spleen are designed to filter tissue fluid, although not necessarily length. The thymus plays a role in development of the immune system. *Tonsils* -Form a ring of lymphatic tissue around the pharynx. This tissue forms a protective barrier for substance entering oral and respiratory passages -May become infected and need to be removed (tonsillectomy). A slight enlargement is not an indication for surgery -Previously removed at the first sign of infection. Today it is known that tonsils provide filtration and protection because they are lymphatic material and are removed only if absolutely necessary *Spleen* -Largest Lymphatic located directly below the diaphragm above left kidney and behind stomach, somewhat flatten, dark purple -Contains lymphoid tissue designed to filter blood -In fetus (along with the liver) has a role in blood cell formation that is later assumed by red bone marrow. In adult, spleen destroys old RBCs and forms bilirubin from hemoglobin -Acts as a reservoir for blood, can be released to body quickly in an emergency. -20-30% of body's platelets are stored here. (In bone marrow failure Spleen may also produce some RBCs) -Filters and destroy pathogens and other foreign materials from the blood. -Also contain specially treated B-lymphocytes that produce antibodies against foreign antigens and T-lymphocytes that attach to invading virus or foreign entities -Monocytes in spleen become macrophages which fight infection by phagocytosis. -Despite its functions, can be removed without Ill effects, however adult more susceptible to some bacterial infection such as pneumonia and meningitis. After removal the liver, bone marrow, and lymph nodes assume some of the spleens function. *Thymus* -Ductless glands in upper chest, under sternum -Important in immune response, although function declines with age. (The thymus begins to atrophy during puberty) -During fetal and early neonatal life, thymus En traps immature stem cells in its reticular structure sensitizing these cells so they are able to mature into specifics type of lymphocytes (eventually become and T cells) -If the thymus fails, the person cell-mediated immunity is non-functioning.