Disorders of Red Blood Cells

Question 1

A complex network of fibrous proteins, especially one called ______, maintains the biconcave shape and flexibility of the red cell membrane that facilitates oxygen transport

Answer 1

spectrin

Question 2

The function of the red blood cell, facilitated by the hemoglobin molecule, is to

Answer 2

transport oxygen to tissues

Question 3

Hemoglobin is a natural pigment. Because of its _____ content, it appears reddish when oxygen is attached and has a bluish cast when deoxygenated.

Answer 3

iron

Question 4

HbF is the predominant hemoglobin in the fetus from the 3rd through the 9th months of gestation. It has a pair of gamma (γ) chains substituted for the α chains. Because of this chain substitution, HbF has a higher affinity for oxygen than HbA.3 This affinity facilitates the transfer of oxygen across the placenta from the HbA in the mother’s blood to the HbF in the fetus’s blood. HbF is generally replaced within ___ months of birth with HbA.

Answer 4

6

Question 5

When red blood cells age and are destroyed in the _____, the iron from their hemoglobin is released into the circulation and returned to the bone marrow for incorporation into new red blood cells or to the liver and other tissues for storage.

Answer 5

spleen

Question 6

Dietary iron also helps to maintain body stores. Iron, principally derived from _____, is absorbed in the small intestine, especially the duodenum

Answer 6

meat

Question 7

__________ refers to the production of red blood cells.

Answer 7

erythropoietin

Question 8

After birth, red cells are produced in the ____ ______ _______. Until 5 years of age, almost all bones produce red cells to meet the growth needs of a child, after which bone marrow activity gradually declines

Answer 8

red bone marrow

Question 9

After 20 years of age, red cell production takes place mainly in the membranous bones of the _______, ______, ____, and _____. With this reduction in activity, the red bone marrow is replaced with fatty yellow bone marrow.

Answer 9

vertebrae
sternum
ribs
pelvis

Question 10

The red blood cells are derived from precursor cells called _________, which are formed continuously from the pluripotent stem cells in the bone marrow

Answer 10

erythroblasts

Question 11

The period from stem cell to emergence of the reticulocyte in the circulation normally takes approximately

Answer 11

1 week

Question 12

Maturation of reticulocyte to erythrocyte takes approximately

Answer 12

24-48 hrs

Question 13

Approximately 1% of the body’s total complement of red blood cells is generated from bone marrow each day, and the reticulocyte count therefore serves as an index of the erythropoietic activity of the

Answer 13

bone marrow

Question 14

Erythropoiesis is governed for the most part by

Answer 14

tissue oxygen needs

Question 15

decreased oxygen content is sensed by the peritubular cells in the kidneys, which then produce a hormone called

Answer 15

erythropoietin

Question 16

Mature red blood cells have a life span of approximately

Answer 16

120 days

Question 17

The destruction of red blood cells is facilitated by a group of large phagocytic cells found in the (4)

Answer 17

liver
spleen
bone marrow
lymphnodes

Question 18

The bulk of the heme unit is converted to ______, the pigment of bile, which is insoluble in plasma and attaches to plasma proteins for transport. Bilirubin is removed from the blood by the liver and conjugated with glucuronide to render it water soluble so that it can be excreted in the bile.

Answer 18

bilirubin

Question 19

The plasma-insoluble form of bilirubin is referred to as __________ bilirubin and water-soluble form is __________ bilirubin

Answer 19

plasma insoluble - unconjugated (indirect)

water soluble - conjugated (direct)

Question 20

If red cell destruction and consequent bilirubin production are excessive, unconjugated bilirubin accumulates in the blood. This results in a yellow discoloration of the skin, called

Answer 20

jaundice

Question 21

With extensive intravascular destruction of red blood cells, hemoglobin levels may exceed the hemoglobin-binding capacity of haptoglobin and other plasma proteins. When this happens, free hemoglobin appears in the blood (this is called _________) and is excreted in the urine (this is called __________).

Answer 21

blood - hemoglobinemia

urine - hemoglobinuria

Question 22

The red blood cell, which lacks mitochondria, relies on ______ and the glycolytic pathway for its metabolic needs.

Answer 22

glucose

Question 23

The depletion of glucose or the functional deficiency of one of the glycolytic enzymes leads to the

Answer 23

premature death of RBCs

Question 24

A hereditary deficiency of ________ predisposes to oxidative denaturation of hemoglobin, with resultant red cell injury and lysis. This is an anemia that is most frequently seen in black men

Answer 24

glucose-6-phosphate dehydrogenase G6PD

Question 25

The percentage of reticulocytes (normally approximately 1%) provides an index of the rate of

Answer 25

red cell production

Question 26

measures the hemoglobin content of the blood.

Answer 26

hemoglobin

Question 27

measures the red cell mass in a 100-mL plasma volume.

Answer 27

hematocrit

Question 28

The hematocrit may be deceptive because it varies with the quantity of extracellular fluid, _______ with dehydration and ______ with overexpansion of extracellular fluid volume

Answer 28

increases in dehydration

decreased in fluid volume excess

Question 29

reflects the volume or size of the red cells. falls in microcytic (small cell) anemia and rises in macrocytic (large cell) anemia.

Answer 29

mean corpuscular volume

Question 30

is the concentration of hemoglobin in each cell.

Answer 30

mean corpuscular hemoglobin concentration

Question 31

refers to the mass of the red cell

Answer 31

mean cell hemoglobin

Question 32

Bone marrow commonly is aspirated with a needle from what two places

Answer 32

posterior iliac crest

sternum

Question 33

Current recommendations suggest transfusion for people with hemoglobin levels less than __ g/dL, depending on age, illness, risk factors, and surgical procedures.

Answer 33

7

Question 34

Acute massive blood loss usually is replaced with

Answer 34

whole blood transfusion

Question 35

Most anemias, however, are treated with transfusions of ____ _____ concentrates, which supply only the blood component that is deficient.

Answer 35

red cell

Question 36

___________ transfusion refers to the procedure of receiving one’s own blood—usually to replenish a surgical loss—thereby eliminating the risk of blood-borne disease or transfusion reaction.

Answer 36

autologous

Question 37

People who have neither A nor B antigens are classified as having type

Answer 37

I

Question 38

Those with A antigens are classified as having type

Answer 38

A

Question 39

those with B antigens, as having type

Answer 39

B

Question 40

those with A and B antigens, as having type ___ blood

Answer 40

AB

Question 41

Persons with type A antigens on their red cells develop type __ antibodies

Answer 41

B

Question 42

persons with type B antigens develop type ___ antibodies in their serum

Answer 42

A

Question 43

people with type __ blood develop type A and type B antibodies

Answer 43

I

Question 44

people with type __ blood develop neither A nor B antibodies

Answer 44

AB

Question 45

The ABO antibodies usually are not present at birth but begin to develop at __ to __ months of age and reach maximum levels between the ages of 5 and 10 years.

Answer 45

3-6

Question 46

People who express the D antigen are designated Rh

Answer 46

positive

Question 47

Unlike serum antibodies for the ABO blood types, which develop spontaneously after birth, Rh antibodies develop after exposure to one or more of the Rh antigens, usually through _________ or transfusions, and persist for many years.

Answer 47

pregnancy

Question 48

More than 80% of Rh-negative people develop the antibody to D antigen if they are exposed to Rh-positive blood. Because it takes several _____ to produce antibodies, a reaction may be delayed and usually is mild.

Answer 48

weeks

Question 49

The most lethal transfusion reaction is the destruction of donor red cells by reaction with antibody in the recipient’s serum. This immediate hemolytic reaction usually is caused by ____ ___________. The signs and symptoms of such a reaction include sensation of heat along the vein where the blood is being infused, flushing of the face, urticaria, headache, pain in the lumbar area, chills, fever, constricting pain in the chest, cramping pain in the abdomen, nausea, vomiting, tachycardia, hypotension, and dyspnea.

Answer 49

ABO incompatibility

Question 50

Hemoglobin that is released from the hemolyzed donor cells is filtered in the glomeruli of the kidneys. Two possible complications of a blood transfusion reaction are oliguria and renal shutdown because of the adverse effects of the filtered hemoglobin on renal tubular flow. The urine should be examined for the presence of (3)

Answer 50

hemoglobin
uroglobin
red blood cells

Question 51

Delayed hemolytic reactions may occur more than 10 days after transfusion and are caused by undetected antibodies in the recipient’s serum. The reaction is accompanied by a fall in _______ and _______, but most recipients are asymptomatic.

Answer 51

hematocrit and jaundice

Question 52

A ______ reaction is the most common transfusion reaction. Recipient antibodies directed against the donor’s white cells or platelets cause chills and fever.

Answer 52

febrile

Question 53

Allergic reactions are caused by a person’s antibodies against donor proteins, particularly ___

Answer 53

IgG - treated with antihistamines

Question 54

_______ is defined as an abnormally low number of circulating red blood cells or level of hemoglobin, or both, resulting in diminished oxygen-carrying capacity.

Answer 54

amelia

Question 55

in ______ anemia, petechiae and purpura (i.e., minute hemorrhagic spots and purplish areas on the skin caused by small vessel bleeding) are the result of reduced platelet function

Answer 55

aplastic

Question 56

It takes about 5 days for the progeny of stem cells to differentiate fully, an event that is marked by increased reticulocytes in the blood. If the bleeding is controlled and sufficient iron stores are available, the red cell concentration returns to normal within

Answer 56

3-4 weeks

Question 57

Chronic blood loss does not affect blood volume but instead leads to what type of anemia?

Answer 57

iron deficiency

Gastrointestinal bleeding and menstrual disorders commonly cause it

Question 58

in iron deficiency anemia, the red cells that are produced have too little hemoglobin, giving rise to ______ _______ anemia

Answer 58

microlytic hypochromic

Question 59

Hemolytic anemia is characterized by (3)

Answer 59

• premature destruction of red cells
• retention in the body of iron and the other products of hemoglobin destruction
• An increase in erythropoiesis

Question 60

Almost all types of hemolytic anemia are distinguished by _______ and _________ red cells.

Answer 60

normocytic and normochromic

Question 61

Because of the red blood cell’s shortened life span in hemolytic anemia, the bone marrow usually is hyperactive, resulting in an increased number of reticulocytes in the

Answer 61

circulating blood

Question 62

Hereditary spherocytosis is mostly transmitted as an ________ ________ trait and is the most common inherited disorder of the red cell membrane.1 The disorder is caused by abnormalities of the spectrin, ankyrin, protein 4.2, or band 3 membrane proteins that lead to a gradual loss of the membrane surface. The loss of membrane relative to cytoplasm causes the cell to lose its lipid bilayer from the RBC cytoskeleton. The RBC forms a spherical shape and cannot easily traverse the spleen.1 Gradually most of these RBCs lose more of their surface membrane and die.

Answer 62

autosomal dominant

Question 63

In parts of Africa, where malaria is endemic, people with _______ _____ anemia have a slight protective effect against Plasmodium falciparum malaria.

Answer 63

sickle cell

Question 64

Sickle cell disease is an inherited disorder in which an abnormal hemoglobin (hemoglobin S [HbS]) leads to chronic hemolytic anemia, pain, and organ failure. The HbS gene is transmitted by _________ inheritance and can manifest as sickle cell trait (i.e., heterozygote with one HbS gene) or sickle cell disease (i.e., homozygote with two HbS genes).

Answer 64

recessive

Question 65

In the homozygote with sickle cell disease, the HbS becomes sickled when

Answer 65

deoxygenated

Question 66

The deoxygenated hemoglobin in sickle cell anemia aggregates and polymerizes in the cytoplasm, creating a semisolid gel that changes the shape and deformability of the cell. The sickled cell may return to normal shape with oxygenation in the lungs. However, after repeated episodes of deoxygenation, the cells become

Answer 66

permanently sickled

Question 67

HbF inhibits the polymerization of HbS. Therefore, most infants with sickle cell disease do not begin to experience the effects of the sickling until after __ to __ weeks of age, when the HbF has been replaced by HbS.

Answer 67

8-10

Question 68

_______ _______ _______ is an atypical pneumonia resulting from pulmonary infarction.11 It is a leading cause of hospitalization in people with sickle cell disease and is characterized by pulmonary infiltrates, which cause dyspnea, cough, and chest discomfort.11 The syndrome can cause chronic respiratory insufficiency and is a leading cause of death in sickle cell disease.

Answer 68

acute chest syndrome

Question 69

Currently, there is no known cure for sickle cell disease. Therefore, treatment strategies focus on prevention of sickling episodes, symptom management, and treatment of complications. The person is advised to avoid situations that precipitate sickling episodes, such as infections, cold exposure, severe physical exertion, acidosis, and dehydration. Infections are aggressively treated, and ______ ________ may be warranted in a crisis or given chronically in severe disease.

Answer 69

blood transfusions

Question 70

Most children with sickle cell disease are at risk for _____ from encapsulated organisms during the first 3 years of life. Maintaining full immunization, including H. influenzae vaccine and Hepatitis B vaccine, is recommended. Hydroxyurea is a cytotoxic drug used to prevent complications of sickle cell disease and is recommended as a standard of care for all with sickle cell disease.12 The drug allows synthesis of more HbF and less HbS, thereby decreasing sickling.

Answer 70

sepsis

Question 71

Like sickle cell disease, the thalassemias occur with high degree of frequency in certain populations. The β-thalassemias, sometimes called Cooley anemia or Mediterranean anemia, are most common in the Mediterranean populations of southern ___ and ____, and the α-thalassemias are most common among Asians. Both β- and α-thalassemias are common in Africans and Americans of African descent.

Answer 71

italy and greece

Question 72

People who are homozygous for the trait (thalassemia major) have severe, blood transfusion–dependent anemia that is evident at 6 to 9 months of age when the hemoglobin switches from HbF to HbA. If transfusion therapy is not started early in life, severe ______ __________ occurs in children with the disorder.

Answer 72

growth retardation

Question 73

_______ _________ is a major complication of β-thalassemia.

Answer 73

iron overload

Excess iron stores, which accumulate from increased dietary absorption and repeated transfusions, are deposited in the myocardium, liver, and endocrine organs and induce organ damage. Cardiac, hepatic, and endocrine diseases are common causes of morbidity and mortality from iron overload.

Question 74

Deletion of three of the four α-chain genes leads to unstable aggregates of α chains called hemoglobin H (HbH). This disorder is the most important clinical form and is common in

Answer 74

asians

Question 75

The most severe form of α-thalassemia occurs in infants in whom all four α-globin genes are deleted and is called

Answer 75

hydrops fetalis syndrome

Hydrops fetalis syndrome usually results in death in utero or shortly after birth.

Question 76

The disorder makes red cells more vulnerable to oxidants and causes direct oxidation of hemoglobin to methemoglobin, which cannot transport oxygen, and denaturing of the hemoglobin molecule to form Heinz bodies, which are precipitated in the red blood cell. Hemolysis usually occurs as the damaged red blood cells move through the narrow vessels of the spleen, causing hemoglobinemia, hemoglobinuria, and jaundice. The hemolysis is short-lived, occurring 2 to 3 days after the trigger event.

Answer 76

G6PD

Question 77

_______ or antiglobulin test, is used to diagnose immune hemolytic anemias. It detects the presence of antibody or complement on the surface of the red cell.

Answer 77

coombs

Question 78

A deficiency of nutrients for hemoglobin synthesis (____) or DNA synthesis (_______ or ____ ____) may reduce red cell production by the bone marrow. A deficiency of red cells also results when the marrow itself fails or is replaced by nonfunctional tissue.

Answer 78

iron

cobalamin or folic acid

Question 79

A child’s growth places extra demands on the body. Blood volume increases, with a greater need for iron. Iron requirements are proportionally higher in infancy (___ to ____ months) than at any other age, although they are also increased in childhood and adolescence. In infancy, the two main causes of iron deficiency anemia are low iron levels at birth because of maternal deficiency and a diet consisting mainly of cow’s milk, which is low in absorbable iron.

Answer 79

3-24

Question 80

Depending on the severity of the anemia, fatigability, palpitations, dyspnea, angina, and tachycardia may occur. Epithelial atrophy is common and results in waxy pallor, brittle hair and nails, sometimes a spoon-shaped deformity of the fingernails called koilonychia, smooth tongue, sores in the corners of the mouth, and sometimes dysphagia and decreased acid secretion.

which type of anemia

Answer 80

iron deficiency anemia

Question 81

The red cells are decreased in number and are

Answer 81

microlytic and hypochromic

Question 82

Low hemoglobin and hematocrit, decreased iron stores, and low serum iron and ferritin characterize ____ ________ anemia. The red cells are decreased in number and are microcytic and hypochromic. Poikilocytosis (irregular shape) and anisocytosis (irregular size) are also present. Laboratory values indicate reduced MCHC and MCV.

Answer 82

iron deficiency

Question 83

Ferrous sulfate, which is the usual oral replacement therapy, replenishes iron stores in

Answer 83

several months

Question 84

_______ ______ and _______ _____ deficiencies are the most common conditions associated with megaloblastic anemias. Because megaloblastic anemias develop slowly, there are often few symptoms until the anemia is far advanced.

Answer 84

vitamin B12 and folic acid

Question 85

_______ ____ also known as cobalamin, serves as a cofactor for two important reactions in humans. It is essential for DNA synthesis and nuclear maturation, which in turn leads to normal red cell maturation and division.

Answer 85

vitamin b12

Question 86

Currently approximately 5% to 20% of older adults have B12 deficiency due to malabsorption, which can be impacted by several different factors such as (3)

Answer 86

PPIs
metformin
gastric bypass

Question 87

true or false

Vitamin B12 is found in all foods of animal origin. Dietary deficiency is rare and usually found only in strict vegetarians who avoid all dairy products as well as meat and fish.

Answer 87

true

Question 88

a specific form of megaloblastic anemia caused by atrophic gastritis and failure to produce intrinsic factor that leads to failure to absorb vitamin B12. It is believed to result from immunologically mediated, possibly autoimmune, destruction of the gastric mucosa. The resultant chronic atrophic gastritis is marked by loss of parietal cells and production of antibodies that interfere with binding of vitamin B12 to intrinsic factor.

Answer 88

Pernicious anemia

Question 89

The MCV is elevated since the cells are larger than normal, and the MCHC is normal.

Answer 89

vitamin b12 def

Question 90

Neurologic changes that accompany the disorder are caused by deranged methylation of myelin protein. Demyelination of the dorsal and lateral columns of the spinal cord causes symmetric paresthesias of the feet and fingers, loss of vibratory and position sense, and eventual spastic ataxia. In more advanced cases, cerebral function may be altered. In some cases, confusion and dementia and other neuropsychiatric changes may precede hematologic changes.

Answer 90

vitamin b12 def

Question 91

the ________ test, which measures the 24-hour urinary excretion of radiolabeled vitamin B12 administered orally, has been used in the past to document decreased absorption of vitamin B12.

Answer 91

schilling

Question 92

______ _____ readily absorbed from the intestine. It is found in vegetables (particularly the green leafy types), fruits, cereals, and meats. Much of the vitamin, however, is lost in cooking. The most common causes of this deficiency are malnutrition or dietary lack, especially in older adults or in association with alcoholism.

Answer 92

folic acid

Question 93

true or false

the clinical manifestations of folic acid deficiency are the same as vitamin b12 def

Answer 93

false

same without neuro symptoms seen in vitamin b12

Question 94

________ anemia describes a disorder of pluripotential bone marrow stem cells that results in a reduction of all three hematopoietic cell lines—red blood cells, white blood cells, and platelets.

Answer 94

aplastic

Question 95

Aplastic anemia can develop in the course of many infections and has been reported most often as a complication of (3)

Answer 95

viral hepatitis
mononucleosis
other viral illnesses such as AIDS

Question 96

The mechanisms underlying the pathogenesis of aplastic anemia are unknown. It is suggested that exposure to the chemicals, infectious agents, and other insults generates a cellular immune response resulting in production of ______ by activated T cells.

Answer 96

cytokines

These cytokines (e.g., interferon, tumor necrosis factor [TNF]) then suppress normal stem cell growth and development.

Question 97

Reticulocyte count in aplastic anemia is _____ since the marrow is not producing any blood cells. The RBC indices indicate normochromic and normocytic anemia.8

Answer 97

0

Question 98

Perhaps one of the most helpful findings to determine the etiology of the pancytopenia is determined in the patient’s history. Most likely the patient has

Answer 98

taken a drug or acquired a virus

Question 99

Therapy for aplastic anemia in the young and severely affected includes stem cell replacement by bone marrow, peripheral blood transplantation, or immunosuppressive therapy. Histocompatible donors supply the stem cells to replace the person’s destroyed marrow cells. what are the two major complications of stem cell transplant

Answer 99

graft vs host and infection

Question 100

anemia of CKD can cause

Answer 100

left ventricular hypertrophy

Question 101

__________ is an abnormally high total red blood cell mass with a hematocrit greater than 54% in men and greater than 47% in women.

Answer 101

polycythemia

Question 102

hematocrit greater than 50% can cause cardiac dysfunction and vascular obstruction, while a hematocrit greater than 60% can lead to

Answer 102

hypoxia

Question 103

in _________ polycythemia, also called Gaisbock syndrome, the hematocrit rises because of a loss of plasma volume without a corresponding decrease in red cells

Answer 103

relative

Question 104

water deprivation, excessive diuretic usage, or gastrointestinal losses may lead to what type of polycythemia

Answer 104

relative

Question 105

Relative polycythemia is corrected by

Answer 105

increasing vascular volume

Question 106

_______ polycythemia is a rise in hematocrit due to an increase in total red cell mass and is classified as primary or secondary.

Answer 106

absolute

Question 107

Primary polycythemia, or ________ ____, is a neoplastic disease of the pluripotent cells of the bone marrow characterized by an absolute increase in total red blood cell mass accompanied by elevated white cell and platelet counts.

Answer 107

polycythemia vera

Question 108

Viscosity rises exponentially with the hematocrit and can interfere with cardiac output and blood flow. _____[[[ is common and there may be complaints of headache, dizziness, inability to concentrate, and some difficulty with hearing and vision because of decreased cerebral blood flow

Answer 108

hypertension

Question 109

Venous stasis seen in ___________ ____ gives rise to a plethoric appearance or dusky redness, even cyanosis, particularly of the lips, fingernails, and mucous membranes.

Answer 109

polycythemia vera

Question 110

The goal of treatment in primary polycythemia is to

Answer 110

reduce blood viscosity

Question 111

________ polycythemia results from a physiologic increase in the level of erythropoietin, commonly as a compensatory response to hypoxia.

Answer 111

secondary

Question 112

Infants who are small for gestational age or born to diabetic or smoking mothers or who experienced hypoxia in utero have higher total hemoglobin levels, higher HbF levels, and a delayed switch to

Answer 112

HbA

Question 113

Anemia at birth, characterized by pallor, congestive heart failure, or shock, usually is caused by

Answer 113

hemolytic disease of the newborn

Question 114

Rarely, cases of hyperbilirubinemia in the neonate are pathologic and may lead to kernicterus and

Answer 114

severe brain damage

Question 115

_______ infants exhibit a slower rise and longer duration of serum bilirubin levels, perhaps because of poor hepatic uptake and reduced albumin binding of bilirubin.

Answer 115

premature

Question 116

Peak bilirubin levels of 8 to 12 mg/dL appear on days 5 to 7. Most neonatal jaundice resolves spontaneously within ___ _____ and is untreated.

Answer 116

1 week

Question 117

Hyperbilirubinemia places the neonate at risk for the development of a neurologic syndrome called _________. This condition is caused by the accumulation of unconjugated bilirubin in brain cells. Unconjugated bilirubin is lipid soluble, crosses the permeable blood–brain barrier of the neonate, and is deposited in cells of the basal ganglia, causing brain damage.

Answer 117

kernicterus

Question 118

_______ _____, or hemolytic disease of the newborn, occurs in Rh-positive infants of Rh-negative mothers who have been sensitized.

Answer 118

erythroblastosis fetalis

Question 119

After an Rh-negative mother has been sensitized, the Rh antibodies from her blood are transferred to subsequent infants through the placental circulation. These antibodies react with the red cell antigens of the Rh-positive infant, causing agglutination and hemolysis. This leads to severe anemia with compensatory hyperplasia and enlargement of the blood-forming organs, including the spleen and liver, in the fetus. Liver function may be impaired, with decreased production of albumin causing massive edema, called ________ ______. If blood levels of unconjugated bilirubin are abnormally high because of red cell hemolysis, there is a danger of kernicterus developing in the infant, resulting in severe brain damage or death.

Answer 119

hydrops fetalis

Question 120

As with other body systems, the capacity for red cell production changes with aging. The location of bone cells involved in red cell production shifts toward the axial skeleton, and the number of progenitor cells _______.

Answer 120

declines

Question 121

true or false

Despite these changes, older adults are able to maintain hemoglobin and hematocrit levels within a range similar to that of younger adults.29 However, during a stress situation such as bleeding, the red blood cells of older adults are not replaced as promptly as those of their younger counterparts.

Answer 121

true

Question 122

__________ __________, which have been found to increase with age, may mediate this reduced sensitivity to erythropoietin.

Answer 122

inflammatory cytokines