Hemoglobin and Oxygen Affinity

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Questions and Answers

What is the effect of 2,3-diphosphoglycerate (2,3-DPG) on hemoglobin's affinity for O2?

Decreases the affinity of hemoglobin for O~2~ (correct)

Converts hemoglobin to methemoglobin

Has no effect on the affinity of hemoglobin for O~2~

Increases the affinity of hemoglobin for O~2~

What is the effect of carbon monoxide on hemoglobin?

Decreases the oxygen-carrying capacity of blood (correct)

Has no effect on the oxygen-carrying capacity of blood

Increases the oxygen-carrying capacity of blood

Converts hemoglobin to methemoglobin

What is the function of neuroglobin in the brain?

Regulates blood pressure in the brain

Helps supply O~2~ to neurons (correct)

Removes excess oxygen from neurons

Has no function in the brain

What is the result of oxidation of hemoglobin?

Formation of methemoglobin Signup and view all the answers

What is the primary difference between α thalassemias and β thalassemias?

Type of polypeptide chains affected Signup and view all the answers

Which type of anemia is caused due to deficiency of intrinsic factor?

Pernicious anemia Signup and view all the answers

What is the term for inherited disorders of hemoglobin production?

Hemoglobinopathies Signup and view all the answers

What is the function of heme in myoglobin?

Binding to oxygen Signup and view all the answers

What is the effect of anemia on circulation?

Increase the work load on the heart Signup and view all the answers

What is the approximate number of abnormal hemoglobins described in humans?

1000 Signup and view all the answers

What is the effect of polycythemia on circulation?

Increase the viscosity of blood Signup and view all the answers

What is the treatment for polycythemia?

Venesection Signup and view all the answers

What is the type of polycythemia caused by high altitude or chronic smoking?

Secondary polycythemia Signup and view all the answers

What is the blood type that has no A or B antigen?

Type O Signup and view all the answers

What is the primary antigen of the Rh blood group system?

D antigen Signup and view all the answers

What is the term used to describe an individual who has the D antigen?

Rh-positive Signup and view all the answers

What percentage of Caucasians are D-negative?

15% Signup and view all the answers

What is the main reason why D-negative individuals do not develop anti-D antibodies naturally?

They are not exposed to D-positive red cells Signup and view all the answers

What is the result of an Rh-negative mother carrying an Rh-positive fetus?

The mother develops anti-Rh agglutinins Signup and view all the answers

What is the percentage of basophils in a normal adult's WBC differential?

0.4 - 1% Signup and view all the answers

What is the average diameter of platelets?

2-4 um Signup and view all the answers

What is the primary function of platelets?

To aggregate at sites of vascular injury Signup and view all the answers

What is the normal range for total WBC in an adult?

4,000 - 11,000 Signup and view all the answers

What is the approximate half-life of platelets in circulation?

4 days Signup and view all the answers

What type of white blood cells are monocytes likely to differentiate into?

Macrophages Signup and view all the answers

What is the percentage of lymphocytes in a normal adult's WBC differential?

25 - 35% Signup and view all the answers

What is the effect of splenectomy on the platelet count?

Increase in platelet count Signup and view all the answers

What is the structure around the periphery of platelets?

A ring of microtubules Signup and view all the answers

Which of the following is a characteristic of newborns shortly after birth?

High white blood cell count Signup and view all the answers

What is the normal range for eosinophils in a normal adult's WBC differential?

1 - 3% Signup and view all the answers

At what age do lymphocytes become less predominant than neutrophils?

8 years Signup and view all the answers

True or False: A relative value of 70% neutrophils is always within normal limits.

False Signup and view all the answers

What is the primary reason for leukocytosis in pregnancy?

Increase in neutrophils Signup and view all the answers

What is the term for an increase in neutrophils?

Neutrophilia Signup and view all the answers

What stimulates the bone marrow to increase white blood cell production?

Colony-stimulating factor (CSF) Signup and view all the answers

What is the term for a WBC count below 4,000?

Leukopenia Signup and view all the answers

What is the effect of corticosteroids on healthy persons?

Increases WBC count Signup and view all the answers

Why may leukocytosis be masked in a patient taking corticosteroids?

Corticosteroids suppress the inflammatory response and the release of WBCs. Signup and view all the answers

What is the term for a temporary and reversible increase in WBC count?

Leukemoid reaction Signup and view all the answers

What is the usual reason for an increase in all five types of leukocytes?

Dehydration and hemoconcentration Signup and view all the answers

Study Notes

Hemoglobin and Oxygen Binding

Hemoglobin's affinity for O2 is affected by pH, temperature, and 2,3-diphosphoglycerate (2,3-DPG) concentration in red cells.
2,3-DPG and H^+^ compete with O2 for binding to deoxygenated hemoglobin, decreasing the affinity for O2.

Hemoglobin Variants

Oxidation: Ferrous iron (Fe^2+^) in hemoglobin is converted to ferric iron (Fe^3+^) by exposure to drugs or oxidizing agents, forming methemoglobin.
Carbon monoxide: Reacts with hemoglobin to form carbon monoxyhemoglobin, displacing O2 and reducing oxygen-carrying capacity.
Heme is also part of myoglobin, found in red (slow) muscles.

Abnormalities of Hemoglobin Production

Inherited disorders: Hemoglobinopathies (abnormal polypeptide chains) and thalassemias (decreased or absent chains due to defects in globin genes).
α thalassemias: Decreased or absent α polypeptides.
β thal-assemias: Decreased or absent β polypeptides.
Abnormal hemoglobins: Over 1000 abnormal hemoglobins have been described in humans.

Anemia

Effects on circulation:
- Decreased viscosity of blood.
- Increased work load on the heart (palpitation and tiredness).

Polycythemia

Increase in RBC production:
- Primary polycythemia vera (count 7-8 million/mm^3).
- Secondary polycythemia due to tissue hypoxia (high altitude or chronic smoking).
Effects on circulation:
- Increased viscosity of blood, leading to sluggish circulation and thrombosis.
- Increased work load on the heart, leading to heart failure.

Blood Transfusions and Blood Typing

ABO blood groups:
- Type A (30-40%): A/A, A/O, O/A.
- Type B (10-30%): B/B, B/O, O/B.
- Type AB (3-5%): A/B or B/A.
- Type O (40-50%): No A or B.
Rh group:
- D antigen: 85% of Caucasians are D-positive, and over 99% of Asians are D-positive.
- D-negative individuals can develop anti-D antibodies after exposure to D-positive blood.

Hemolytic Disease of the Newborn

Rh incompatibility: D-negative mother carrying a D-positive fetus, leading to maternal sensitization and potential hemolysis in the fetus.

Platelets (Thrombocytes)

Small, granulated bodies that aggregate at sites of vascular injury.
Lack nuclei, and have a half-life of about 4 days.
Formed by megakaryocytes in the bone marrow.
Released into circulation, with about 60-75% in circulation and the remainder in the spleen.

White Blood Cells (Leukocytes)

Agranulocytes:
- Lymphocytes (25-35%): Involved in immune responses.
- Monocytes (4-6%): Differentiate to become macrophages, with serious appetites for infectious microbes.
Granulocytes:
- Neutrophils (50-70%): Primary responders to infections.
- Eosinophils (1-3%): Involved in parasitic infections and allergic reactions.
- Basophils (0.4-1%): Release histamine, causing inflammation, vasodilation, and attraction of WBCs.

Leukopoiesis and Colony Stimulating Factors (CSFs)

CSFs stimulate bone marrow to increase WBC production.
Leukocytosis: Increase in WBC count, often due to an increase in one type of WBC.
Leukopenia: Decrease in WBC count below 4,000.

Corticosteroids and Infection

Corticosteroids can mask infection by suppressing the inflammatory response and WBC release.
Masking of infection can lead to undiagnosed spreading of infection.

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Description

Learn about the factors that affect hemoglobin's affinity for oxygen, including pH, temperature, and 2,3-diphosphoglycerate. Understand how these factors influence the binding of oxygen to hemoglobin.