Biomolecules in Red Blood Cells

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Questions and Answers

What method is used for the indirect measurement of hemoglobin concentration?

Electrode Method

Cyanmethemoglobin Method (correct)

Ferrous Method

Direct Hemoglobin Method

What is the final color of the solution when hemoglobin reacts with Drabkin's solution?

Cyan or Blue (correct)

Green

Yellow

Red

Which component of Drabkin’s solution converts methemoglobin to cyanohemoglobin?

Potassium Ferricyanide

Surfactant

Potassium Cyanide (correct)

Sodium Bicarbonate

What is the typical lifespan of reticulocytes in circulation before they mature into red blood cells?

1 day Signup and view all the answers

What is the standard reference range for hemoglobin concentration in males?

13.5-18.0 g/dL Signup and view all the answers

Which purpose does sodium bicarbonate serve in Drabkin's Solution?

Accelerates the reaction time Signup and view all the answers

In what form are young red blood cells known as reticulocytes found in the body?

In the bone marrow and circulation Signup and view all the answers

What is the significance of the color intensity of the cyanmethemoglobin solution?

Proportional to hemoglobin concentration Signup and view all the answers

What is the primary purpose of the Miller Disk in hematology?

To facilitate the counting of reticulocytes Signup and view all the answers

In the formula for calculating reticulocyte percentage, which value corresponds to the number of cells counted in the larger square?

Number of cells in square A Signup and view all the answers

Which factor can significantly affect the accuracy of manual reticulocyte counts?

Expertise of the technician Signup and view all the answers

What effect does improper staining time have on reticulocyte visibility?

Leads to under- or overstaining Signup and view all the answers

What condition is typically associated with elevated reticulocyte values?

Hemolytic anemias Signup and view all the answers

Which of the following is a potential source of error related to dye quality during reticulocyte counting?

Poor quality of supravital stain Signup and view all the answers

Which error can occur due to platelet clumping when counting reticulocytes?

Falsely elevated reticulocyte counts Signup and view all the answers

What is a constant factor used in the calculation of reticulocyte percentage?

100 Signup and view all the answers

What is the primary function of proteins in the body?

Structural, functional, and transport roles Signup and view all the answers

What percentage of the total biochemical composition do lipids represent?

40% Signup and view all the answers

Which process occurs during extravascular destruction of red blood cells?

Lysis of RBC within macrophages Signup and view all the answers

What occurs to iron during the breakdown of hemoglobin?

It is recycled and stored as ferritin Signup and view all the answers

Which of the following is part of the intravascular destruction process?

Release of hemoglobin into plasma Signup and view all the answers

What is the final product of protoporphyrin degradation?

Bilirubin Signup and view all the answers

Which substance is filtered and reabsorbed by the proximal convoluted tubule (PCT) during intravascular RBC destruction?

Free hemoglobin Signup and view all the answers

What happens to iron within the tubular cell during the intravascular breakdown of RBCs?

It is stored as hemosiderin Signup and view all the answers

What is thalassemia primarily characterized by?

Reduced or absent production of hemoglobin chains Signup and view all the answers

Which enzyme deficiency is known to affect red blood cells' ability to maintain reduced glutathione levels?

Glucose-6-Phosphate Dehydrogenase Deficiency Signup and view all the answers

Hereditary spherocytosis is caused by a deficiency in which of the following proteins?

Spectrin or Ankyrin Signup and view all the answers

Which condition is associated with increased susceptibility to oxidative stress in red blood cells?

Glucose-6-Phosphate Dehydrogenase Deficiency Signup and view all the answers

Which of the following disorders is characterized by the formation of elliptically shaped red blood cells?

Hereditary elliptocytosis Signup and view all the answers

Abetalipoproteinemia primarily affects the integrity of what component in red blood cells?

Membrane Signup and view all the answers

What characteristic feature makes spherocytes more prone to destruction in the spleen?

Loss of membrane surface area Signup and view all the answers

What is a common consequence of Pyruvate Kinase Deficiency in red blood cells?

Reduced ATP production Signup and view all the answers

What is the formula for calculating the relative value of a specific cell type?

Relative Value (%) = (Number of specific cells / Total number of cells) x 100 Signup and view all the answers

If a patient's total WBC count is 10,000 cells/µL and the relative value of neutrophils is 10%, what is the absolute neutrophil count?

1,000 cells/µL Signup and view all the answers

What is the standard reference value for a corrected reticulocyte count (CRC)?

1-3% Signup and view all the answers

How is the Reticulocyte Production Index (RPI) calculated?

RPI = CRC / Maturation time (days) Signup and view all the answers

What does a Reticulocyte Production Index (RPI) value greater than 1 indicate?

Increased reticulocyte production Signup and view all the answers

What is the primary use of a calibrated Miller Disc in hematology?

To facilitate accurate size measurement of cells Signup and view all the answers

What type of cells does a reticulocyte count assess?

Immature red blood cells Signup and view all the answers

What adjustment does the Corrected Reticulocyte Count (CRC) perform?

Adjusted for hematocrit level Signup and view all the answers

Study Notes

Biomolecules and Their Functions in Red Blood Cells

Proteins constitute 52% of RBC's biomolecules and are responsible for structural integrity, functional processes, and transportation of molecules, vital for maintaining shape, stability, and gas exchange.
Lipids make up 40% and contribute to the flexibility and fluidity of the RBC membrane, forming a semi-permeable barrier that controls the passage of substances.
Carbohydrates compose 8% and play roles in immune recognition, establishing a negative surface charge, and contributing to blood group antigenicity.

Red Blood Cell Breakdown

Extravascular Hemolysis:
- Occurs primarily in the spleen, liver, and bone marrow.
- Aged RBCs are phagocytized by macrophages.
- Hemoglobin is released from the RBCs.
- The heme is converted to bilirubin and excreted in the bile.
- Globin is broken down into amino acids.
- Iron is recycled and stored as ferritin.
Intravascular Hemolysis:
- Occurs directly in the blood vessels.
- Characterized by RBC fragmentation or mechanical lysis.
- Hemoglobin is released and binds to haptoglobin.
- The haptoglobin-hemoglobin complex is carried to the liver for further processing.
- Some hemoglobin is filtered by the kidneys, reabsorbed by the proximal convoluted tubules, and eventually excreted in the urine if renal threshold is exceeded.

Hemoglobin Determination

Cyanohemoglobin Method (Hemoglobin Cyanide Method/ Ferricyanide Method):
- A commonly used method for hemoglobin determination.
- Uses Drabkin’s solution containing potassium ferricyanide, sodium bicarbonate, and a surfactant.
- Converts hemoglobin to cyanohemoglobin (stable pigment) which has a blue color.
- Color intensity of the solution is directly proportional to the hemoglobin concentration.

Reticulocyte Count

Reticulocytes are immature red blood cells which contain RNA and are released from the bone marrow.
Reticulocyte count reflects the rate at which new RBCs are being produced by the bone marrow.
Relative Reticulocyte Count: Calculated by dividing the number of reticulocytes by the total number of red blood cells.
Absolute Reticulocyte Count: Calculated by multiplying the relative reticulocyte count by the total red blood cell count.
Corrected Reticulocyte Count (CRC): Adjusts the reticulocyte count to account for the patient's hematocrit value.
Reticulocyte Production Index (RPI): A more refined measure of reticulocyte production, considering the reticulocyte maturation time.

Using the Calibrated Miller Disc

Calibrated Miller Disc: A tool used for accurate size comparison of microscopic specimens.
Reticulocyte Count: The Miller Disc allows for standardized reticulocyte counting, providing greater accuracy.

Potential Errors in Manual Reticulocyte Counting

Subjective interpretation of cells.
Inaccurate cell counting.
Poor dye quality or improper staining time.
Inadequate slide preparation .
Hemolysis or platelet clumping.
Mistakes in calculations.

Conditions Affecting Reticulocyte Values

Increased Reticulocyte Values:
- Hemolytic anemias (sickle cell anemia, autoimmune hemolytic anemia).
- Thalassemia.
- Enzyme deficiencies (G6PD deficiency, pyruvate kinase deficiency).
Decreased Reticulocyte Values:
- Bone marrow suppression (e.g., due to chemotherapy, radiation, or certain infections).
- Iron deficiency anemia.
- Vitamin B12 or folate deficiency.

Intrinsic Defects Leading to Increased Red Blood Cell Destruction

Membrane Defects:
- Hereditary spherocytosis.
- Hereditary elliptocytosis.
- Hereditary stomatocytosis.
- Abetalipoproteinemia.

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Description

Explore the essential roles of proteins, lipids, and carbohydrates in red blood cells. Understand how these biomolecules contribute to the structural integrity, flexibility, and functionality of RBCs. This quiz will also cover the processes involved in the breakdown of red blood cells.