Chapter 17 Objectives Anatomy and Physiology II
Define thrombocytopenia
A condition in which the number of circulating platelets is deficient, thrombocytopenia causes spontaneous bleeding from small blood vessels all over the body.
Explain how oxygen is carried on hemoglobin
A hemoglobin molecule can transport four molecules of oxygen because each iron atom can combine reversibly with one molecule of oxygen.
Identify factors that limit or prevent undesirable clot formation.
As long as the endothelium is smooth and intact, platelets are prevented from clinging and piling up. Also, antithrombic substances- nitric oxide and prostacyclin-secreted by the endothelial cells normally prevent platelet adhesion. Additionally, vitamin E quinone, a molecule formed in the body when vitamin E reacts with oxygen, is a potent anticoagulant.
Describe why blood is categorized as a connective tissue
Blood is the only fluid tissue in the body. Has both cellular and liquid components. It is a specialized type of connective tissue in which living blood cells, called the formed elements, are suspended in a nonliving fluid matrix called plasma. the collagen and elastic fibers typical of other connective tissues are absent from blood, but dissolved fibrous proteins become visible as fibrin strands during blood clotting
Describe blood plasma and state the functions of albumin in plasma.
Blood plasma is a straw-colored, sticky fluid. Although it is mostly water (about 90%), plasma contains over 100 different dissolved solutes, including nutrients, gases, hormones, wastes and products of cell activity, proteins, and inorganic ions (electrolytes). Electrolytes vastly outnumber the other solutes. Albumin accounts for some 60% of plasma protein. It acts as a carrier to shuttle certain molecules through the circulation, is an important blood buffer, and is the major blood protein contributing to the plasma osmotic pressure (the pressure that helps to keep water in the bloodstream).
Define Diapedesis
But white blood cells are able to slip out of the capillary blood vessels-a process
Define erythropoiesis
Erythrocyte production
Describe how erythropoiesis is controlled.
Erythrocyte production, or erythropoiesis, begins when a hematopoietic stem cell descendant called a myeloid stem cell transforms into a proerythroblast.
Define hematocrit, state the normal ranges for males and females, and describe how a hematocrit is determined.
Erythrocytes normally constitute about 45% of the total volume of a blood sample, a percentage known as the hematocrit. Normal hematocrit values vary. In healthy males the norm is 47% _+ 5%; in females it is 42% __+ 5%.
Include in your description the roles of hypoxia, bone marrow, and erythropoietin (EPO), the source of EPO, and the mechanism of control.
Erythropoietin, a glycoprotein hormone, stimulates the formation of erythrocytes. Normally, a small amount of EPO circulates in the blood at all times and sustains red blood cell production at a basal rate. The kidneys play the major role in EPO production, although the liver also produces some. When certain kidney cells become hypoxic (oxygen deficient), oxygen-sensitive enzymes are unable to carry out their normal functions of degrading an intracellular signaling molecule called hypoxia-inducible factor (HIF).
Define petechiae
Even normal movement leads to widespread hemorrhage, evidenced by many small purplish spots on the skin.
Identify the common progenitor cell for all formed elements in blood.
Hemocytoblast
Describe how plasma or blood can be appropriately expanded; state what not an appropriate volume expander is.
Plasma expanders (purified human serum albumin, plasminate, and dextran) that increase fluid volume of blood. Hypertonic or hypotonic solution is not an appropriate volume expander.
Describe primary (polycythemia Vera) and secondary polycythemias and state how these relate to blood doping.
Polycythemia Vera, a bone marrow cancer, is characterized by dizziness and an exceptionally high RBC count (8-11 million cells/ul). Secondary polycythemias result when less oxygen is available or EPO production increases. The secondary polycythemia that appears in individuals living at high altitudes is a normal physiological response to the reduced atmospheric pressure and lower oxygen content of the air in such areas. RBC counts of 6-8 million/ul are common in such people. Blood doping, practiced by some athletes competing in aerobic events, is artificially induced polycythemia.
Define oxyhemoglobin
When oxygen binds to iron; assumes a new three-dimensional shape and becomes a ruby red.
Define fibrinolysis
a clot is not a permanent solution to blood vessel injury, and a process called fibrinolysis removes unneeded clots when healing has occurred.
Define Iron-deficiency
inadequate iron in the body
Define Plasma Cell
produce antibodies that are released to the blood.
Describe the 3 functions of blood.
1) Distribution 2)Regulation 3) Protection
Describe the life cycle of erythrocytes including their fate and destruction.
1. Low O2 levels in blood stimulate kidneys to produce erythropoietin. 2. Erythropoietin levels rise in blood. 3. Erythropoietin and necessary raw materials in blood promote erythropoiesis in red bone marrow. 4. New erythrocytes enter bloodstream; function about 120 days. 5. Aged and damaged red blood cells are engulfed by macrophages of spleen, liver, and bone marrow; the hemoglobin is broken down. 6. Raw materials are made available in blood for erythrocyte synthesis.
Compare and contrast thrombus and embolus
A clot that develops and persists in a unbroken blood vessel is called a thrombus. If the thrombus breaks away from the vessel wall and floats freely in the bloodstream, it becomes an embolus.
Define leukocytosis
A white blood cell count of over 11,000 cells/ul
Define carbaminohemoglobin
About 20% of the carbon dioxide transported in the blood combines with hemoglobin, but it binds to globin's amino acids rather than to the heme group. This formation of carbaminohemoglobin occurs more readily when hemoglobin is in the reduced state. Carbon dioxide loading occurs in the tissues, and the direction of transport is from tissues to lungs, where carbon dioxide is eliminated from the body.
Identify human ABO blood groups by description or depiction (by blood typing) of the antigens and antibodies that a patient contains. Describe Rh blood grouping and state a major difference between the Rh and ABO blood grouping systems. Describe a transfusion reaction.
Blood Group AB: A, B, AB, O "Universal Recipient" Blood Group B: B,O Blood Group A: A, O Blood Group O: O " Universal Donor" Unlike the ABO system antibodies, anti-Rh antibodies do not spontaneously form in the blood of Rh-(Rh negative) individuals. When mismatched blood is infused, a transfusion reaction occurs in which the recipient's plasma antibodies attack the donor's red blood cells.
Define hematopoiesis
Blood cell formation
Describe the two components of blood
Blood is a specialized connective tissue in which living blood cells, called the formed elements, are suspended in a nonliving fluid matrix called plasma.
State some physical characteristics of blood and the normal blood volumes of males and females.
Blood is a sticky, opaque fluid with a characteristic metallic taste. Depending on the amount of oxygen it is carrying, the color of blood varies from scarlet (oxygen rich) to dark red (oxygen poor). Blood is more dense than water and about five times more viscous, largely because of its formed elements. Erythrocytes are the major factor contributing to blood viscosity. Women typically have a lower red blood cell count than men [4.2-5.4 million cells per microliter of blood versus 4.7-6.1 million cells]. When the number of red blood cells increases beyond the normal range, blood becomes more viscous and flows more slowly. Similarly, as the number of red blood cells drops below the lower end of the range, the blood thins and flows more rapidly.
Define the terms granulocyte and agranulocyte and state the relative abundances of the granulocytes and agranulocytes.
Granulocyte: which include neutrophils, eosinophils, and basophils, are all roughly spherical in shape. They are larger and much shorter-lived than erythrocytes. Agranulocyte: include lymphocytes and monocytes, WBCs that lack visible cytoplasmic granules. Although similar to each other structurally, they are functionally distinct and unrelated cell types. Their nuclei are typically spherical or kidney shaped.
Describe a hemoglobin molecule.
Hemoglobin, the protein that makes red blood cells red, binds easily and reversibly with oxygen, and most oxygen carried in blood is bound to hemoglobin.
Define hemorrhagic
Hemorrhagic anemia is caused by blood loss
Describe homeostasis and the three phases involved in the process. Include in this description the role of platelets, von Willebrand factor, serotonin, ADP, and thromboxane A2.
If a blood vessel wall breaks, a whole series of reactions is set in motion to accomplish homeostasis, which stops the bleeding. The hemostasis response if fast, localized, and carefully controlled. It involves many clotting factors normally present in plasma as well as several substances that are released by platelets and injured tissue cells. During hemostasis, three steps occur in rapid sequence: 1) Vascular Spasm 2) Platelet plug formation, and 3) coagulation (blood clotting). In the second set, platelets play a key role in hemostasis by aggregating (sticking together), forming a plug that temporarily seals the break in the vessel wall). They also help orchestrate subsequent events that form a blood clot. A large plasma protein called von Willebrand factor stabilizes bound platelets by forming a bridge between collagen and platelets. Setotonin and thromboxane A2-messengers that enhance vascular spasm and platelet aggregation Adenosine diphosphate- a potent aggregating agent that causes more platelets to stick to the area and release their contents.
Define hemolytic
In hemolytic anemias, erythrocytes rupture, or lyse, prematurely.
Describe the general structure and functions of leukocytes.
Leukocytes, or white blood cells (WBCs), are the only formed elements that are complete cells, with nuclei and the usual organelles. Leukocytes are crucial to our defense against disease. They form a mobile army that helps protect the body from damage by bacteria, viruses, parasites, toxins, and tumor cells. As such, they have special functional characteristics.
Define leukopoiesis and describe how this process in controlled and what factors are involved.
Like erythropoiesis, leukopoiesis, or the production of white blood cells, is stimulated by chemical messengers. These messengers, which can act either as paracrines or hormones, are glycoproteins that fall into two families of hematopoietic factors, interleukins and colony-stimulating factors, or CSFs.
Describe the 2 general types of agranulocytes
Lymphocytes: accounting for 25% or more of the WBC population, are the second most numerous leukocytes in the blood. Large numbers of lymphocytes exist in the body, but relatively few (mostly the small lymphocytes) are found in the blood stream. In fact, lymphocytes are so called because most are closely associated with lymphoid tissues, where they play a crucial role in immunity. Monocytes: account for 3-8% of WBCs. When circulating monocytes leave the bloodstream and enter the tissues, they differentiate into highly mobile macrophages with prodigious appetites.
Describe the 3 types of granulocytes; include in your description the functions of each type.
Neutrophils, the most numerous white blood cells, account for 50-70% of the WBC population. Neutrophils are about twice as large as erythrocytes. Neutrophils are our body's bacteria slayers, and their numbers increase explosively during acute bacterial infections such as meningitis and appendicitis. Eosinophils account for 2-4% of all leukocytes and are approximately the size of neutrophils. Their nucleus usually has two lobes connected by a broad band of nuclear material and so resembles ear muffs. The most important role of eosinophils is to lead the counterattack against parasitic worms, such as flatworms (tapeworms and flukes) and roundworms (pinworms and hookworms) that are too large to be phagocytized. Basophils are the rarest white blood cells, accounting for only 0.5-1% of the leukocyte population.
Define defensins
Others, especially the smaller granules, contain a potent "brew" of antimicrobial proteins.
State the life-span of an erythrocyte and where the destruction occurs.
Red blood cells have a useful life span of 100 to 120 days. Red blood cells are unable to synthesize new proteins, grow, or divide. Erythrocytes become "old" as they lose their flexibility, become increasingly rigid and fragile, and their hemoglobin begins to degenerate. They become trapped and fragment in smaller circulatory channels, particularly in those of the spleen. For this reason, the spleen is sometimes called the "red blood cell graveyard." Macrophages engulf and destroy dying erythrocytes. The heme of their hemoglobin is split off from globin. Its core of iron is salvaged, bound to protein, and stored for reuse. The balance of the heme group is degraded to bilirubin, a yellow pigment that is released to the blood and binds to albumin for transport. Liver cells pick up bilirubin and in turn secrete it (in bile) into the intestine, where it is metabolized to urobilinogen. Most of this degraded pigment leaves the body in feces, as a brown pigment called stercobilin. The protein (globin) part of hemoglobin is metabolized or broken down to amino acids, which are released to the circulation.
Contrast the functions of T and B lymphocytes.
T lymphocytes (T cells) function in the immune response by acting directly against virus-infected cells and tumor cells. B lymphocytes (B cells) give rise to plasma cells, which produce antibodies (immunoglobulins) that are released to the blood.
State the three causes of anemia and give examples of each of these causes.
The causes of anemia can be divided into three groups: blood loss, not enough red blood cells produced, or too many of them destroyed.
List the formed elements of blood and sort them as either true cells or not true cells. State the source of these formed elements.
The formed elements of blood- erythrocytes, leukocytes, and platelets. Two of the three are not even true cells: Erythrocytes have no nuclei or organelles, and platelets are cell fragments. Only leukocytes are complete cells. Most blood cells do not divide. Instead, stem cells divide continuously in red bone marrow to replace them.
State the cell that is the source of all formed elements in blood.
The various formed elements have different functions, but there are similarities in their life histories. All arise from the hematopoietic stem cell, sometimes called a hemocytoblast.
Define anemia
a condition in which the blood's oxygen-carrying capacity is too low to support normal metabolism.
Define reticulocyte and state what a reticulocyte count indicates.
a young erythrocyte, so named because it still contains a scant reticulum (network) of clumped ribosomes. Reticulocyte counts provide a rough index of the rate of RBC formation-reticulocyte counts below or above this range indicate abnormal rates of erythrocyte formation.
Define deoxyhemoglobin
a. In the tissues, oxygen detaches from iron, Hb resumes former shape b. reduced hemoglobin, becomes dark red.
Define macrophage
actively phagocytic, and they are crucial in the body's defense against viruses, certain intracellular bacterial parasites, and chronic infections such as tuberculosis.
Define leucopenia
an abnormal low white blood cell count, commonly induced by drugs, particularly glucocorticoids and anticancer agents.
Define Histamine
an inflammatory chemical that acts as a vasodilator (makes blood vessels dilate) and attracts other white blood cells to the inflamed site; drugs called antihistamines counter this effect.
Describe platelets; include in your description the source of these elements, their function, and what regulates their formation.
are not cells int he strict sense. About one-fourth the diameter of a lymphocyte, they are cytoplasmic fragments of extraordinarily large cells called megakaryotes. In blood smears, each platelet exhibits blue-staining outer region and an inner area containing granules that stain purple. Platelets are essential for the clotting process that occurs in plasma when blood vessels are ruptured of their lining is injured. By sticking to the damaged site, platelets for a temporary plug that helps seal the break. Because they are anucleate, platelets age quickly and degenerate in about 10 days if they are not involved in clotting. A hormone called thrombopoietin regulates the formation of platelets.
Define Pernicious
autoimmune disease that most often affects the elderly
Infectious Monouncleosis
called the "kissing disease," is a highly contagious viral disease most often seen in young adults.
Define aplastic
may result from destruction or inhibition of the red marrow by certain drugs and chemicals, ionizing radiation, or viruses.
Define Leukemia (acute)
quickly advancing, if it derives from stem cells.
Define Hemophilia
refers to several hereditary bleeding disorders that have similar signs and symptoms.
Define Leukemia (chronic)
slowly advancing, if it involves proliferation of later cell stages.
Define Sickle-cell anemias
the havoc caused by the abnormal hemoglobin, hemoglobin S (HbS), results from a change in just one of the 146 amino acids in a beta chain of the globin molecule!
Define Thalassemia
typically occur in people of Mediterranean ancestry. One of the globin chains is absent or faulty, and the erythrocytes are thin, delicate, and deficient in hemoglobin.
