Chapter 27: Structure and Function of the Hematologic System

The EOSINOPHIL count is high in the first year of life and is higher in children than in adolescents and adults. Monocyte counts are high in the first year of life and ???

decrease to adult levels.

Lymphocyte function appears to ???

decrease with age. Particularly affected is a decrease in cellular immunity.

Plasmin is a ??? enzyme of fibrin clots.

degrading

Platelets are not cells—they are ???. Platelets are essential for ???.

disk-shaped cytoplasmic fragments blood coagulation and control of bleeding

Platelets develop from megakaryocytes by a process called ???, which is controlled by thrombopoietin.

endomitosis

The ??? prevents the formation of spontaneous clots in normal vessels by several anticoagulant mechanisms.

endothelium

These cells make up 42% to 48% of blood volume.

erythrocytes plasma is the rest

The cellular elements of blood are the ???

erythrocytes (red blood cells), leukocytes (white blood cells), and platelets (thrombocytes).

8. Erythropoiesis (production of erythrocytes) is regulated by ???.

erythropoietin

In response to the change from a placental to a pulmonary oxygen supply during the first few days of life, levels of ??? decrease.

erythropoietin and the rate of blood cell formation

The coagulation cascade is composed of intrinsic and extrinsic pathways, with the ??? being dominant.

extrinsic pathway

Products of fibrinolysis include???

fibrin degradation products, such as D-dimer.

mesenchymal stem cells develop into ???

fibroblasts osteoclasts adipocytes

The immunoglobulins, including gamma globulins, are responsible for???

fighting infection.

Neutrophils, basophils, and eosinophils are ???

granulocytes

Functionally, lymph nodes are part of the ??? systems.

hematologic and immune

Iron homeostasis is controlled by ???, a small hormone produced by hepatocytes, which regulates ???, the principal transporter of iron from stores in hepatocytes and macrophages and from intestinal cells that take up dietary iron.

hepcidin ferroportin

The LYMPHOCYTE count is ??? at birth, rises further during the first year of life, and steadily declines until ???.

high lower adult volumes are reached.

Platelet adhesiveness probably ??? with age.

increases

Leukocytes defend the body against ???

infection and remove dead or injured host cells.

Erythropoietin is secreted by the ??? in response to ??? and causes a compensatory increase in ??? if the oxygen content of the blood decreases because of anemia, high altitude, or pulmonary disease.

kidneys tissue hypoxia erythrocyte production

Albumin molecules are ???

large and do not freely diffuse through the vascular endothelium

Blood flows into the lymph nodes through the ???

lymphatic artery

13. The lymph nodes are the site of development or activity of large numbers of ???

lymphocytes, monocytes, and macrophages.

Monocytes may mature into ??? in the circulation and migrate out of the vessels in response to ???

macrophages infection or inflammation.

14. The MPS is composed of ???

macrophages in tissue and lymphoid organs.

During endomitosis the megakaryocytes undergo ??? but not cell division and the cytoplasm and plasma membrane fragment into platelets.

mitosis

The agranulocytes include ???

monocytes and macrophages.

Granulocytes and monocytes in the blood develop from common ??? under the direction of several growth factors, including stem cell factor,???

myeloid progenitor cells in the bone marrow IL-3, and GM-CSF.

The ??? is the earliest cell involved in inflammation.

neutrophil

Leukocytes are classified as either granulocytes (???) or agranulocytes (???).

neutrophils, basophils, eosinophils monocytes, macrophages, lymphocytes

platelets have no ??? and ??? divide.

nucleus cannot

Erythrocytes do not have a ???; therefore they cannot divide or synthesize proteins.

nucleus or mitochondria

Antithrombin III is a circulating ???

plasma protease inhibitor that inhibits thrombin and factor Xa.

??? is produced from plasminogen by activation of plasminogen activators (t-PA, u-PA), thrombin, fibrin, factor XIIa, factor XIa, and kallikrein.

plasmin

Fibrinolysis (breakdown of blood clots) is the function of the ???

plasminogen-plasmin system.

They are disk-shaped fragments that form from megakaryocytes, and have cytoplasmic components

platelets

The neutrophil is the most abundant leukocyte (approximately 55% of the leukocytes) and is the ???.

primary granulocyte that defends against infections.

3. A blood clot is a meshwork of ??? that stabilizes the platelet plug. The strands are made of ???.

protein strands fibrin

4. Bone marrow consists of???

red and yellow marrow. Red = hematopoietic marrow (blood vessels, mononuclear phagocytes, stem cells, blood cells in various stages of differentiation, stromal cells) yellow = fatty tissue

15. The MPS is the main line of defense against bacteria in the bloodstream and cleanses the blood by???

removing old, injured, or dead blood cells; antigen-antibody complexes; and macromolecules.

3. Hematopoiesis continues throughout life to ???

replace blood cells that grow old and die, are killed by disease, or are lost through bleeding.

The lymphoid organs are sites of ??? of lymphocytes and mononuclear phagocytes.

residence, proliferation, differentiation, and function

Blood cell counts ??? adult levels at birth and then gradually decline throughout childhood.

rise above

The ??? is the largest of the secondary lymphoid organs and functions as the site of hematopoiesis in the fetus, filters and cleanses the blood, and is a reservoir for lymphocytes and other blood cells.

spleen

5. The bone marrow contains multiple populations of ???;

stem cells Mesenchymal stem cells --> fibroblasts osteoclasts adipocytes hematopoietic stem cells --> blood cells

Lymph nodes collect interstitial fluid and eventually return it to circulation via the ???

superior vena cava.

Specific hematopoietic growth factors (e.g., colony-stimulating factors) are necessary for ???

the adequate production of myeloid, erythroid, lymphoid, and megakaryocytic lineages.

Clotting factors are responsible for ???

the clotting cascade and the formation of blood clots.

The lymphoid organs are classified as primary (???) or secondary (???).

thymus and bone marrow spleen, lymph nodes, tonsils, and Peyer patches of the small intestine

The extrinsic pathway is activated when ??? is released from damaged endothelial cells.

tissue factor

Erythrocytes carry hemoglobin, are responsible for ???

tissue oxygenation

The iron cycle reutilizes iron released from old or damaged erythrocytes. Iron binds to ??? in the blood, is transported to ??? of the MPS, and is stored in the cytoplasm as ???

transferrin macrophages ferritin.

Nitric oxide causes ???.

vasodilation

Platelet activation involves three linked processes: ???

(1) adhesion, (2) activation, and (3) aggregation.

2. Platelet activation involves three linked processes: ???

(a) adhesion, (b) activation, and (c) aggregation.

2. Hematopoiesis involves two stages: ??

(a) proliferation, and (b) maturation.

Cells contained in the marrow specimen are assessed with respect to: ???

(a) relative numbers of stem cells and their developing daughter cells, and (b) morphologic structure.

Hemostasis, or arrest of bleeding in damaged vessels, involves: ???

(a) vasoconstriction, (b) damage to the endothelium and exposure of connective tissue resulting in formation of a platelet plug, (c) activation of the clotting cascade, (d) formation of a blood clot, and (e) activation of fibrinolysis for clot retraction and clot dissolution.

Eosinophil granules contain a variety of enzymes ??? that help control the inflammatory processes.

(e.g., histaminase)

anticoagulant mechanisms used by the endothelium

--production of NO and PGI2, thrombin inhibitors (antithrombin III), and tissue factor inhibitors --degradation of activated clotting factors (thrombomodulin-protein C).

In adults the total blood volume is approximately ???

5.5 L.

The adult blood volume is approximately

5.5 L. or 6 quarts.

Plasma accounts for ??? of blood volume.

50% to 55%

The normal erythrocyte life span is ??? in full-term infants, 20 to 30 days in premature infants, and ??? in children, adolescents, and adults.

60 to 80 days 120 days

The average blood volume of an infant is ??? which is similar to that of older children and adults.

75 to 77 ml/kg,

Plasma is made up of ???

8% dissolved substances and 92% water.

Blood consists of cells suspended in a solution of about ???

90% water and 10% solutes.

erythrocyte changes with age

A delay in erythrocyte replenishment may occur after bleeding, presumably because of iron deficiency.

9. Platelet activation involves which processes? (Select all that apply.) A. Adhesion B. Aggregation C. Inhibition D. Cyclooxygenase-1 (COX-1) inactivation

A. Adhesion B. Aggregation

8. Which statements are true regarding lymph nodes? (Select all that apply.) A. Lymph nodes collect interstitial fluid. B. Lymph nodes are part of the hematologic and immune system. C. Eventually lymph nodes return lymph to circulation via the inferior vena cava. D. Lymph nodes may enlarge and become tender as a result of infection. E. Blood flows into the lymph node via the afferent lymph vessels.

A. Lymph nodes collect interstitial fluid. B. Lymph nodes are part of the hematologic and immune system. D. Lymph nodes may enlarge and become tender as a result of infection.

7. Which of the following is a granulocyte? (Select all that apply.) A. Neutrophil B. Basophil C. Eosinophil D. Monocyte E. Macrophage

A. Neutrophil B. Basophil C. Eosinophil

5. Which statement is true regarding platelets? A. Platelets are disk-shaped cytoplasmic fragments. B. Platelets are formed by clumps of megakaryocytes. C. Platelets have a large nucleus. D. Platelets divide rapidly.

A. Platelets are disk-shaped cytoplasmic fragments.

2. Which component of the blood system is responsible for the critical colloid oncotic pressure? A. Immunoglobulins B. Albumin C. Gamma globulins D. Clotting factors

B. Albumin

1. Which statement is true regarding the constituents of blood? A. Plasma is made up of 90% dissolved substances and 10% water. B. Blood volume in adults is approximately 6 quarts. C. Plasma accounts for 10% of blood volume. D. Plasma and serum are identical in composition.

B. Blood volume in adults is approximately 6 quarts.

4. Which cells are the predominant cells of early inflammation? A. Monocyte B. Neutrophil C. Basophil D. Eosinophil

B. Neutrophil

3. Which statement is true regarding erythrocytes? A. Erythrocytes make up 80% of blood volume. B. They are responsible for tissue oxygenation. C. Erythrocytes contain mitochondria. D. They actively synthesize proteins.

B. They are responsible for tissue oxygenation.

6. Which of the following is responsible for lysis or the breakdown of blood clots? A. Nitric oxide B. Tissue factor C. Antithrombin III D. Fibrinolytic system

D. Fibrinolytic system

??? are responsible for tissue oxygenation.

Erythrocytes

??? is the end product of the coagulation cascade.

Fibrin

1.???, or blood cell production, occurs in the liver and spleen of the fetus and in the bone marrow after birth.

Hematopoiesis

???, the oxygen-carrying protein of the erythrocyte, enables the blood to transport 100 times more oxygen than could be transported dissolved in plasma alone.

Hemoglobin

??? may result in lymph node enlargement and tenderness (reactive lymph node).

Infection

??? are fewer in number than erythrocytes and constitute approximately 5000 to 10,000 cells/mm3 of blood.

Leukocytes

??? are the primary cells of the immune response.

Lymphocytes

The intrinsic pathway is initiated by TF that forms a complex with the ???

TF/VIIa complex.

Erythrocytes are the most ??? of the blood, occupying approximately 48% of the blood volume in men and approximately 42% in women

abundant cells

The NEUTROPHIL count is very high at birth, falls to ???, and is the same as that for adults by 4 years of age.

adult ranges after 2 weeks

Platelet counts in full-term infants are comparable with those in ??? and remain so throughout childhood.

adults

Plasma, the liquid portion of the blood, contains two major groups of proteins: ???

albumins and globulins.

Basophils are often increased at sites of ???

allergic inflammatory reactions and parasitic infection, particularly exoparasitic (e.g., ticks) infection.

Plasma differs from serum in that serum is ???

altered in the laboratory by removing fibrinogen and other clotting factors.

Monocytes, basophils, and eosinophils may be part of the inflammatory response but ???

are not the earliest cellular response. --> Neutrophils are

Tests of bone marrow function include bone marrow aspiration and bone marrow biopsy.

biopsy.

hematopoietic stem cells develop into ???

blood cells.

6. Regulation of hematopoiesis occurs in specialized microenvironments (niches) in the ??? In which hematopoietic stem cells are signaled to undergo ??? and through direct contact with ??? or vascular endothelial cells, as well as several other specialized cells, including ???

bone marrow differentiation through the effects of multiple cytokines and chemokines osteoblasts CAR cells and nestin-expressing cells.

Soon after bacterial invasion or tissue injury, neutrophils migrate out of the ??? and into the inflamed site.

capillaries

Blood composition ???

changes little with age.

Albumin molecules are large and do not freely diffuse through the vascular endothelium, and therefore maintain the critical ??? that regulates the passage of water and solutes into the surrounding tissues.

colloidal osmotic pressure (or oncotic pressure)

Platelets are not cells but fragments of ???

cytoplasmic components.