1. Disorders of Hematologic System

What are the components of the hematologic system?

Blood, blood vessels, and bone marrow.

What are the chief functions of the hematologic system?

1. Delivery of substances needed for cellular metabolism

2. Removal of wastes

3. Defense against microorganisms and injury

4. Maintenance of acid-base balance

What is the most abundant cell in the body?

Erythrocytes (RBCs).

What is the function of erythrocytes?

Responsible for tissue oxygenation.

What two structural characteristics make RBCs ideal for gas exchange?

Biconcavity and reversible deformity.

What is the life cycle of an erythrocyte?

120 days.

What is the buffy coat, and what percentage of blood does it make up?

The buffy coat is the thin middle layer of blood containing white blood cells (WBCs) and platelets; it makes up 2% of blood.

What is the function of leukocytes (WBCs)?

They defend the body against infection and remove debris.

What are the two main categories of leukocytes?

Granulocytes and agranulocytes.

What are the types of granulocytes?

Neutrophils, basophils, and eosinophils.

What are the types of agranulocytes?

Monocytes, macrophages, and lymphocytes.

H and H

Hemoglobin (H): A protein in red blood cells that carries oxygen throughout the body.
Hematocrit (H): The percentage of red blood cells in the total volume of blood. 

• hemoglobin x 3

What are erythrocytes derived from?

Erythrocytes are derived from erythroblasts (normoblasts).

What stimulates the maturation of red blood cells (RBCs)?

Erythropoietin.

What is the function of erythropoietin?

It causes an increase in red cell production and is released from the bone marrow.

What vitamins are necessary for erythropoiesis?

Vitamin B12, folate, B6, riboflavin, and others.

What is required for vitamin B12 transport across the ileum?

Intrinsic factor, which is secreted by parietal cells.

Where are B12 and folate stored?

In the liver and used as needed.

What is the definition of anemia?

A reduction in the total number of erythrocytes (RBCs) in circulating blood or in the quality or quantity of hemoglobin.

What lab values are typically seen in anemia?

• Slightly lower than normal may not cause symptoms.

• Hgb at 7-8 g/dL and Hct at 21-22% usually result in symptoms.

What are the main causes of anemia?

1. Impaired erythrocyte production

2. Acute or chronic blood loss

3. Increased erythrocyte destruction

4. A combination of the above

How is anemia classified?

By its causes or by changes affecting the size, shape, or substance of RBCs.

What suffix is used to describe RBC size in anemia classification?

-cytic (e.g., macrocytic, microcytic, normocytic).

What are the three classifications of RBC size in anemia?

• Macrocytic – Large RBCs

• Microcytic – Small RBCs

• Normocytic – Normal-sized RBCs

What suffix is used to describe hemoglobin concentration in anemia classification?

-chromic (e.g., normochromic, hypochromic).

What are the two classifications of hemoglobin concentration in anemia?

• Normochromic – Normal hemoglobin concentration

• Hypochromic – Low hemoglobin concentration

What is the primary physiological manifestation of anemia?

Reduced oxygen-carrying capacity leading to tissue hypoxia.

What determines the symptoms of anemia?

The severity of anemia and the body's ability to compensate.

How does the body respond to mild versus severe anemia over time?

Mild cases may show little compensation, while severe cases over time usually result in more compensation.

What are the classic symptoms of anemia, regardless of the cause?

1. Fatigue

2. Weakness

3. Dyspnea (shortness of breath)

4. Pallor (pale skin)

How does the body compensate for anemia-related blood loss?

By moving interstitial fluid into the blood to increase plasma volume.

What happens to blood consistency when plasma volume increases?

The blood becomes thinner (less viscous).

How does thinner blood affect circulation?

It flows differently, increasing heart rate (HR) and stroke volume (SV).

What can prolonged anemia-related compensation lead to if not corrected?

Cardiac dilation.

What is hypoxemia in the context of anemia?

A reduced oxygen level in the blood.

How does hypoxemia affect blood vessels?

It dilates arterioles and capillaries, increasing blood flow.

• the body attempts to increase oxygen delivery to tissues.

How does increased blood flow due to hypoxemia affect the heart?

It further increases heart rate (HR) and stroke volume (SV).

What can prolonged increased HR and SV due to anemia lead to?

Heart failure.

How does tissue hypoxia affect the pulmonary system?

It increases the rate and depth of breathing to deliver more oxygen to tissues.

What are the respiratory effects of anemia?

Increased effort to breathe, leading to shortness of breath.

What common symptoms result from tissue hypoxia in anemia?

• Shortness of breath

• Rapid heartbeat

• Dizziness

• Fatigue

• Pallor (paleness of the skin)

What are some other manifestations of anemia?

• Impaired healing

• Loss of skin elasticity

• Weakness

• Numbness

• Nausea

• Emesis (vomiting)

• Change in appetite

How does acute anemia related to blood loss present?

It does not go through stages slowly and causes immediate physiological responses.

What is the initial reaction in acute blood loss anemia?

Vasoconstriction and shunting of blood to vital organs.

• in the case of acute blood loss anemia, the body initiates vasoconstriction (narrowing of blood vessels) rather than dilation because the goal is to maintain blood pressure and preserve blood flow to vital organs like the heart and brain.

What do the terms "macrocytic" and "normochromic" mean in the context of anemia?

• Macrocytic: Large RBCs.

• Normochromic: Normal hemoglobin concentration.

What are the two types of macrocytic-normochromic anemias?

Pernicious anemia and folate deficiency anemia.

What causes macrocytic-normochromic anemias?

Defective DNA synthesis, usually caused by deficiencies in vitamin B12 or folate.

How do defective RBCs contribute to anemia in macrocytic-normochromic anemias?

Defective RBCs die prematurely, decreasing the number of RBCs and causing anemia.

What is the cause of pernicious anemia (PA)?

Vitamin B12 deficiency.

Which populations are most commonly affected by pernicious anemia?

Individuals over 30 of Northern European descent, Hispanics, African Americans, and more commonly females.

How does pernicious anemia develop over time?

Symptoms occur slowly over several years.

What autoimmune disorder is often associated with pernicious anemia?

Chronic gastritis, which leads to the destruction of parietal cells.

What other factors can contribute to pernicious anemia?

• Alcoholism

• Liver disease

• Hypothyroidism

• Cigarette smoking

• Surgery removing the stomach

What causes pernicious anemia (PA)?

A lack of intrinsic factor (IF) from the gastric parietal cells.

How can intrinsic factor (IF) deficiency occur?

It may be congenital, autoimmune, or due to gastric mucosal atrophy.

What is congenital IF deficiency?

It is caused by autosomal recessive inheritance.

How does autoimmune IF deficiency differ?

It has a familial component.

Why is intrinsic factor (IF) important for vitamin B12 absorption?

IF is required for the absorption of vitamin B12 in the ileum, which is needed for RBC nucleus maturation and DNA synthesis.

What results from a vitamin B12 deficiency in pernicious anemia?

Defective RBCs, leading to anemia, and neurological symptoms.

What are some neurological symptoms of pernicious anemia?

1. Paresthesia of extremities

2. Difficulty walking
   (These result from nerve demyelination.)

What other symptoms may occur with pernicious anemia?

• Loss of appetite

• Abdominal pain

• Beefy red tongue (atrophic glossitis)

• Splenic or liver enlargement

Is pernicious anemia (PA) curable?

No, pernicious anemia is not curable.

How is pernicious anemia treated?

Treatment involves injections (or high oral doses) of vitamin B12.

What role does folate play in the body?

Folate is required for RNA and DNA synthesis within RBCs.

How is folate obtained and absorbed?

Folate is exclusively obtained from the diet and absorbed in the upper small intestine.

Where is folate stored in the body?

Folate circulates through the body and is stored in the liver.

Who is most likely to develop folate deficiency anemia?

It is common in those who are malnourished, such as those on extreme dieting, fad diets, or with alcoholism.

What are the symptoms of folate deficiency anemia?

Symptoms are similar to pernicious anemia, except neurological manifestations are generally not seen.

What are some additional symptoms of folate deficiency anemia?

• Burning mouth syndrome

• Dysphagia (difficulty swallowing)

• Flatulence

• Watery diarrhea

How is folate deficiency anemia treated?

Treatment requires daily oral administration of folate.

What do the terms "microcytic" and "hypochromic" mean in the context of anemia?

• Microcytic: Abnormally small red blood cells (RBCs).

• Hypochromic: RBCs containing reduced amounts of hemoglobin.

What are microcytic-hypochromic anemias related to?

They are related to disorders of iron metabolism.

Who is more likely to develop iron deficiency anemia?

Females are more likely than males, especially during menstruation and pregnancy.

Who is at higher risk for iron deficiency anemia?

1. Individuals living in poverty

2. Persons with lead poisoning

3. Infants (due to their increased need for iron)

4. Males in childhood and teen years

What factors can decrease the risk of iron deficiency anemia in women?

The risk decreases after menopause.

What are the most common causes of iron deficiency anemia?

• Pregnancy

• Continued blood loss

What causes iron deficiency anemia at the pathophysiological level?

Depleted iron stores and reduced hemoglobin synthesis.

What are common causes of iron deficiency anemia due to inadequate iron intake or chronic blood loss?

• Ulcers

• Excessive menses

• Cirrhosis

• Hemorrhoids

• Cancer

• Surgery

• Medications that cause gastrointestinal tract bleeding

What are the early manifestations of iron deficiency anemia?

• Fatigue

• Weakness

• Shortness of breath

• Pale ear lobes, palms, and conjunctiva

What are the late manifestations of iron deficiency anemia?

• Brittle, thin, coarsely ridged, and spoon-shaped nails (koilonychia)

• A red, sore, and painful atrophied tongue

• Dry, sore corners of mouth (angular stomatitis)

How quickly can symptoms of iron deficiency anemia improve with treatment?

Symptoms can reverse after 1-2 weeks of iron replacement.

What is essential for treating iron deficiency anemia?

Finding and fixing the underlying cause of the iron deficiency.

What do the terms "normocytic" and "normochromic" mean in the context of anemia?

• Normocytic: Red blood cells (RBCs) that are relatively normal in size.

• Normochromic: RBCs with normal hemoglobin content.

What is characteristic of normocytic-normochromic anemias?

These anemias are characterized by red blood cells that are normal in size and hemoglobin content but insufficient in number.

What are some examples of normocytic-normochromic anemias?

• Posthemorrhagic anemia

• Sickle Cell Disease

What is the cause of posthemorrhagic anemia?

Excessive bleeding (hemorrhage), which decreases blood volume and oxygen to tissues.

How does posthemorrhagic anemia affect iron stores?

It typically does not affect iron stores, as they remain normal despite blood loss.

What can happen if posthemorrhagic anemia is not reversed?

It can lead to death if not treated.

What is the inheritance pattern of sickle cell disease (SCD)?

Autosomal recessive.

Which populations are more commonly affected by sickle cell disease (SCD)?

More common in African and Mediterranean populations.

What causes the sickling of red blood cells in sickle cell disease?

A point mutation in the DNA triplet coding for glutamic acid (CTC) that codes for valine (CAC) instead, causing poor oxygenation and dehydration.

What factors influence the severity of sickle cell disease?

Severity depends on the level of dehydration and oxygenation.

What are the effects of sickled red blood cells (RBCs) in sickle cell disease?

• Increased blood viscosity

• Slower blood movement through the body

• Vascular occlusion

What is the inheritance pattern of sickle cell trait?

Child inherits normal genetic material from one parent and the mutation from another, making them heterozygous.

Do individuals with sickle cell trait experience symptoms of sickle cell disease?

No, individuals with sickle cell trait do not have symptoms of sickle cell disease.

Can individuals with sickle cell trait pass it to their offspring?

Yes, individuals with sickle cell trait can pass the trait to their offspring.

Why is it important to know if the other parent also has sickle cell trait?

If both parents have the trait, genetic analysis can help determine the probabilities of their child having either the trait or the disease.

What is a vaso-occlusive crisis in sickle cell disease?

A vaso-occlusive crisis involves vasospasm and obstruction, leading to thrombosis formation and potential organ damage, with decreased oxygenation to distal tissues.

What are the manifestations of sickle cell disease during a crisis?

Manifestations include generalized and joint pain, jaundice, weakness, and fatigue.

What causes coagulation disorders?

Coagulation disorders are caused by gene deletions and point mutations that impact the production and function of clotting factors.