BLOOD

coagulation

Clotting; the process of changing from a liquid to a solid, said especially of blood

hypoxia

Deficiency in the amount of oxygen reaching body tissues.

Transport

Delivering oxygen from the lungs and nutrients from the digestive tract to all body cells. Transporting metabolic waste products from cells to elimination sites (to the lungs to eliminate carbon dioxide, and to the kidneys to dispose of nitrogenous wastes in urine). Transporting hormones from the endocrine organs to their target organs.

Platelets

Disk-shaped structures in blood that promote clotting.

How many molecules of oxygen can each hemoglobin molecule transport? What part of the hemoglobin binds the oxygen?

Each hemoglobin molecule can transport four O2. The heme portion of the hemoglobin binds the O2.

What is the key difference between fibrinogen and fibrin? Between prothrombin and thrombin? Between most factors before and after they are activated?

Fibrinogen is water soluble, whereas fibrin is not. Prothrombin is an inactive precursor, whereas thrombin acts as an enzyme. Most factors are inactive in blood before activation and become enzymes upon activation. (There are exceptions, such as fibrinogen and calcium.)

Emily Wong, 17, is brought to the ER with a fever, headache, and stiff neck. You suspect bacterial meningitis. Would you expect to see an elevated neutrophil count in a differential WBC count? Explain.

If Emily has a bacterial meningitis, a differential WBC count would likely reveal an increase in neutrophils because neutrophils are a major body defense against bacteria.

CBC

Includes counts of the different types of formed elements, the hematocrit, measurements of hemoglobin content, and size of RBCs.

Structural Characteristics of erythrocytes

Its small size and shape provide a huge surface area relative to volume (about 30% more surface area than comparable spherical cells). Discounting water content, an erythrocyte is over 97% hemoglobin, the molecule that binds to and transports respiratory gases. Because erythrocytes lack mitochondria and generate ATP by anaerobic mechanisms, they do not consume any of the oxygen they carry, making them very efficient oxygen transporters.

Regulation

Maintaining appropriate body temperature by absorbing and distributing heat throughout the body and to the skin surface to encourage heat loss. Maintaining normal pH in body tissues. Maintaining adequate fluid volume in the circulatory system.

MAKING CONNECTIONS: Because of the blood brain barrier, the brain is largely inaccessible to circulating macrophages. Instead (as we discussed in Chapter 11), one type of CNS cell (related to macrophages) can become phagocytic. Which type of cell is this?

Microglial cells can become phagocytes in the brain.

Which WBCs turn into macrophages in tissues? Which other WBC is a voracious phagocyte

Monocytes become macrophages in tissues. Neutrophils are also voracious phagocytes.

Formed Elements

Most types of formed elements survive in the bloodstream for only a few days. Two of the three are not even true cells. Most blood cells do not divide. Instead, stem cells divide continuously in red bone marrow to replace them.

Nigel is told he has type B blood. Which ABO antibodies does he have in his plasma? Which agglutinogens are on his RBCs? Could he donate blood to an AB recipient? Could he receive blood from an AB donor? Explain.

Nigel has anti-A antibodies in his blood and type B agglutinogens on his RBCs. He can donate blood to an AB recipient, but he should not receive blood from an AB donor because his anti-A antibodies will cause a transfusion reaction.

Embolism

Obstruction or occlusion of a blood vessel by an embolus.

Are plasma proteins used as fuel for body cells? Explain your answer.

Plasma proteins are not used as fuel for body cells because their presence in blood is required to perform many key functions.m

Protection

Preventing blood loss. Preventing infection.

packed red blood cells

Red blood cells that have been separated from plasma. They are used to treat conditions such as hemorrhage or symptomatic anemias that require transfusions of red blood cells but not the liquid components of whole blood.

The drop in normal blood oxygen levels that triggers EPO formation can result from:

Reduced numbers of red blood cells due to hemorrhage (bleeding) or excessive RBC destruction Insufficient hemoglobin per RBC (as in iron deficiency) Reduced availability of oxygen, as might occur at high altitudes or during pneumonia

Serotonin and thromboxane A2

Serotonin and thromboxane A2 messengers that enhance vascular spasm and platelet aggregations

clotting factors, or procoagulants

Substances in the blood that act in sequence to stop bleeding by forming a clot.

leukopoiesis

The formation or production of white blood cells

What is the hematocrit? What is its normal value?

The hematocrit is the percentage of blood that is occupied by erythrocytes. It is normally about 45%.

Patients with advanced kidney disease often have anemia. Explain the connection.

The kidneys' synthesis of erythropoietin is compromised in advanced kidney disease, so RBC production decreases, causing anemia.

diapedesis

The movement or passage of blood cells, especially white blood cells, through intact capillary walls into surrounding body tissue.

Regulation and Requirements for Erythropoiesis

The number of circulating erythrocytes in a given individual is remarkably constant and reflects a balance between red blood cell production and destruction.

hematocrit

The percentage by volume of packed red blood cells in a given sample of blood after centrifugation.

Blood doing

The process of increasing the number of circulating red blood cells in order to increase the oxygen-carrying capacity of the blood for improved athletic endurance, performed by blood transfusion or administering erythropoietin.

hemostasis

The stoppage of bleeding or hemorrhage.

What are the three steps of hemostasis?

The three steps of hemostasis are vascular spasm, platelet plug formation, and coagulation.

buffy coat

This layer contains leukocytes (leuko = white),the white blood cells that act in various ways to protect the body, and platelets, cell fragments that help stop bleeding.

Which bleeding disorder results from not having enough platelets? From absence of clotting factor VIII?

Thrombocytopenia (platelet deficiency) results in failure to plug the countless small tears in blood vessels, and so manifests as small purple spots. Hemophilia A results from the absence of clotting factor VIII.

Granulocytes

White blood cells with cytoplasm that contains granules.

Volume

Women typically have a lower red blood cell count than men [4.2-5.4 million cells per microliter (1 μl = 1 mm3) of blood versus 4.7-6.1 million cells/μl respectively].

urobilinogen

a chromogen formed in the intestine from the breakdown of bilirubin; yields urobilins on oxidation; some is excreted in the feces and some is resorbed and excreted in bile or urine

antihemophilic factor

a coagulation factor (trade name Hemofil) whose absence is associated with hemophilia A

Hydroxyurea

a drug used to treat chronic leukemia, switches the fetal hemoglobin gene back on. This drug dramatically reduces the excruciating pain and overall severity and complications of sickle-cell anemia (by 50%)

colony-stimulating factors

a group of glycoprotein growth factors regulating differentiation of myeloid cells. These substances act in either paracrine or autocrine fashion on marrow cells; appear to act synergistically in complex and poorly understood ways; each seems to have the ability to exert action on several lines of progenitor cells, and to influence end cell function.

monoblast

a large immature monocyte normally found in bone marrow

promyelocytes

a precursor in the granulocytic series, intermediate between myeloblast and myelocyte, containing a few undifferentiated cytoplasmic granules

vascular spasm

a sudden constriction of the blood vessels causing reduction or stoppage in blood flow.

tissue plasminogen activator

a thrombolytic agent (trade name Activase) that causes fibrinolysis at the site of a blood clot; used in treating acute myocardial infarction

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.

Monocytes

account for 3-8% of WBCs. With an average diameter of 18 μm, they are the largest leukocytes.

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).

Renal anemia

anemia occurring as a complication of chronic kidney disease, mainly caused by deficiency of erythropoietin in the blood.

macrophages

are actively phagocytic, and they are crucial in the body's defense against viruses, certain intracellular bacterial parasites, and chronic infections such as tuberculosis. Tissues and lymphatic tissues

Basophils

are the rarest white blood cells, accounting for only 0.5-1% of the leukocyte population. Their cytoplasm contains large, coarse, histamine-containing granules that have an affinity for the basic dyes and stain purplish-black.

Bleeding disorders

arise from abnormalities that prevent normal clot formation.

Functions of Erythrocytes

completely dedicated to their job of transporting respiratory gases (oxygen and carbon dioxide)

Erythropoietin

glycoprotein hormone, stimulates the formation of erythrocytes.

Disseminated intravascular coagulation (DIC)

has characteristics of both types of disorder, involves both widespread clotting and severe bleeding.

Mononucleosis

he presence of an abnormally large number of white blood cells with single nuclei in the bloodstream.

CMP

is a blood chemistry profile that measures various electrolytes, glucose, and markers of liver and kidney disorders.

promonocyte

is a cell arising from a monoblast and developing into a monocyte.

Anemia

is a condition in which the blood's oxygen-carrying capacity is too low to support normal metabolism.

megakaryoblast

is a precursor cell to a promegakaryocyte

Polycythemia

is an abnormal excess of erythrocytes that increases blood viscosity, causing it to flow sluggishly.

Aspirin

is an antiprostaglandin drug that inhibits thromboxane A2 formation (blocking platelet aggregation and platelet plug formation).

proerythroblast (or rubriblast, or pronormoblast)

is the earliest of four stages in development of the normoblast.

respiratory burst

is the rapid release of reactive oxygen species (superoxide radical and hydrogen peroxide) from different types of cells.

Platelet-derived growth factor

it plays a significant role in blood vessel formation (angiogenesis), the growth of blood vessels from already-existing blood vessel tissue.

What is a megakaryocyte? What does its name mean?

megakaryocyte is a cell that produces platelets. Its name means "big nucleus cell."

basophilic erythroblasts

produce huge numbers of ribosomes.

thrombopoietin

regulates the formation of platelets.

fibrinolysis

removes unneeded clots when healing has occurred.

Thromboembolic disorders

result from conditions that cause undesirable clot formation

clot retraction

the drawing away of a blood clot from the wall of a vessel, a stage of wound healing caused by contraction of platelets; it is a function of blood platelets that can be tested to assess platelet viability.

intrinsic pathway

the factors needed for clotting are present within the blood. Triggered by negatively charged surfaces such as activated platelets, collagen, or glass. (This is why this pathway can initiate clotting in a test tube.) Slower because it has many intermediate steps.

megakaryocyte

the giant cell of bone marrow; it is a large cell with a greatly lobulated nucleus, and is generally supposed to give rise to blood platelets

sickle-cell anemia

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! This alteration causes the beta chains to link together under low-oxygen conditions, forming stiff rods so that hemoglobin S becomes spiky and sharp.

Neutrophils

the most numerous white blood cells, account for 50-70% of the WBC population. They are about twice as large as erythrocytes.

Heparin

the natural anticoagulant contained in basophil and mast cell granules, is also found on the surface of endothelial cells.

extrinsic pathway

the tissue factor it requires is outside of blood. Triggered by exposing blood to a factor found in tissues underneath the damaged endothelium. This factor is called tissue factor (TF) or factor III. Faster because it bypasses several steps of the intrinsic pathway. In severe tissue trauma, it can form a clot in 15 seconds.

positive chemotaxis

they pinpoint areas of tissue damage and infection and gather there in large numbers to destroy foreign substances and dead cells.

Thalassemias

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.

polymorphonuclear leukocytes

white blood cells with nuclei of varied forms

Band cell

(also called band neutrophil or stab cell) is a cell undergoing granulopoiesis, derived from a metamyelocyte, and leading to a mature granulocyte.

defensins

A class of basic antibiotic polypeptides, found in neutrophils, which kills bacteria by causing membrane damage.

stercobilin

A coloring matter found in the fæces, a product of the alteration of the bile pigments in the intestinal canal, - identical with hydrobilirubin.

Thrombocytopenia

A condition in which the number of circulating platelets is deficient, it causes spontaneous bleeding from small blood vessels all over the body.

thrombus

A fibrinous clot formed in a blood vessel or chamber of the heart

Thrombus

A fibrinous clot formed in a blood vessel or chamber of the heart.

Aplastic anemia

A form of anemia in which the capacity of the bone marrow to generate red blood cells is defective. This anemia may be caused by bone marrow disease or exposure to toxic agents, such as radiation, chemicals, or drugs.

intrinsic factor

A glycoprotein that is secreted by the gastric mucous membrane and is essential for the absorption of vitamin B12 in the intestines

myelocyte

A large cell of the bone marrow that is a precursor of the mature granulocyte of the blood.

Embolus

A mass, such as an air bubble, a detached blood clot, or a foreign body, that travels through the bloodstream and lodges so as to obstruct or occlude a blood vessel.

embolus

A mass, such as an air bubble, a detached blood clot, or a foreign body, that travels through the bloodstream and lodges so as to obstruct or occlude a blood vessel.

prothrombin

A plasma protein that is converted into thrombin during blood clotting.

Adenosine diphosphate (ADP)

A potent aggregating agent that causes more platelets to stick to the area and release their contents

prostacyclin

A prostaglandin produced in the walls of blood vessels that acts as a vasodilator and inhibits platelet aggregation.

thrombin

A protease in blood that facilitates blood clotting by converting fibrinogen to fibrin

fibrinogen

A protein in the blood plasma that is essential for the coagulation of blood and is converted to fibrin by the action of thrombin in the presence of ionized calcium.

Spectrin

A protein of high molecular weight that is a major component of the membrane of red blood cells. Adds flexibility

Antithrombin III

A protein present in plasma, quickly inactivates any thrombin not bound to fibrin.

plasmin

A proteolytic enzyme that is formed from plasminogen in blood plasma and dissolves the fibrin in blood clots.

interleukins

A range of CYTOKINES secreted by white cells of the immune system.

bilirubin

A reddish-yellow bile pigment, C33H36N4O6, derived from the degradation of heme

agglutinins

A substance, such as an antibody, that is capable of causing agglutination of a particular antigen, especially red blood cells or bacteria.

ABO blood groups

A system in which human blood is classified by whether the red blood cells contain A or B antigens. Type A blood has the A antigen; type B has the B antigen, AB has both, and 0 has neither.

prothrombin time

A test belongs to a group of blood tests that assess the clotting ability of blood.

Plasma

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).

Amos has leukemia. Even though his WBC count is abnormally high, Amos is prone to severe infections, bleeding, and anemia. Explain.

Amos's red bone marrow is spewing out many abnormal white blood cells, which are crowding out the production of normal bone marrow elements. The lack of normal white blood cells allows the infections, the low number of platelets fails to stop bleeding, and the lack of erythrocytes is anemia.

leukocytosis

An abnormally large increase in the number of white blood cells in the blood, often occurring during an acute infection or inflammation.

Macrocytes

An abnormally large red blood cell, especially one associated with pernicious anemia.

Leukopenia

An abnormally low number of leukocytes in the circulating blood.

microcytes

An abnormally small red blood cell that is less than five microns in diameter and may occur in certain forms of anemia.

Fibrin

An elastic, insoluble, whitish protein produced by the action of thrombin on fibrinogen and forming an interlacing fibrous network in the coagulation of blood

polychromatic erythroblast

An erythrocyte that does not stain uniformly.

orthochromatic erythroblast

An erythrocyte that stains with acid stains only, the cytoplasm appearing pink.

myeloblasts

An immature cell of the bone marrow that is the precursor of a myelocyte.

reticulocyte

An immature red blood cell that contains a network of basophilic filaments

hemosiderin

An insoluble protein that contains iron, is produced by phagocytic digestion of hematin that is released during hemolysis of hemoglobin, and is found as granules in most tissues, especially the liver.

ferritin

An iron-containing protein complex, found principally in the intestinal mucosa, spleen, and liver, that functions as the primary form of iron storage in the body.

hemolytic anemias

Anemia resulting from the lysis of red blood cells, as in response to certain toxic or infectious agents and in certain inherited blood disorders

hemophilia

Any of several sex-linked genetic disorders, manifested almost exclusively in males, in which the blood fails to clot normally because of a deficiency or an abnormality of one of the clotting factors.

T lymphocytes

Any of the lymphocytes that mature in the thymus and have the ability to recognize specific peptide antigens through the receptors on their cell surface.

B lymphocytes

Any of the lymphocytes that when stimulated by a particular antigen differentiate into plasma cells and that in mammals mature in the bone marrow.

Production of Erythrocytes

Blood cell formation is referred to as hematopoiesis (hem″ah-to-poi-e′sis; hemato = blood; poiesis = to make). Hematopoiesis occurs in the red bone marrow, which is composed largely of a soft network of reticular connective tissue bordering on wide blood capillaries called blood sinusoids.

Physical Characteristics

Blood is a sticky, opaque fluid with a characteristic metallic taste.