Iron Transport Mechanisms Quiz

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Questions and Answers

What is the primary role of plasmapheresis in iron transport?

To enhance the absorption of dietary iron

To collect iron from the enterocytes (correct)

To store excess iron as ferritin

To convert iron into its ferrous form

Which vitamin is essential for the first step in the synthesis of porphyrin?

Vitamin E

Vitamin B6 (correct)

Vitamin C

Vitamin D

What process is responsible for the internalization of the transferrin-iron complex in normoblasts?

Facilitated diffusion

Exocytosis

Simple diffusion

Endocytosis (correct)

What component is required to render iron into its ferric form for transport?

Ceruloplasmin Signup and view all the answers

Which of the following is responsible for the characteristic blue staining of normoblast cytoplasm?

Presence of RNA-containing ribosomes Signup and view all the answers

What characterizes toxic granulation in neutrophils?

Purple-grey cytoplasmic granules Signup and view all the answers

Which classification indicates a platelet count of less than 50.0 × 10^9/L?

Thrombocytopenia Signup and view all the answers

Which condition is associated with the presence of reactive lymphocytes?

Immunological stimulation Signup and view all the answers

What is a common clinical sign associated with anaemia?

Pale mucous membranes Signup and view all the answers

What does the presence of active monocytes indicate?

Phagocytic activity in diseases Signup and view all the answers

What is the main manifestation of cytoplasmic vacuolisation in neutrophils?

Foamy appearance Signup and view all the answers

Which of the following is NOT a characteristic of thrombocytopenia?

Normal platelet morphology Signup and view all the answers

What type of cellular change is indicated by the presence of Döhle bodies?

Severe bacterial infection Signup and view all the answers

What role does sialic acid play in trans-membrane proteins?

It aids in cell adhesion. Signup and view all the answers

What is the primary function of ankyrin in the erythrocyte membrane?

To anchor integral proteins to contractile proteins. Signup and view all the answers

What is a potential cause for the activation of antibodies leading to cold-agglutinin disease?

Lower temperatures than 37ºC Signup and view all the answers

Which statement is true about the calcium concentration in erythrocytes?

It is significantly lower than in plasma. Signup and view all the answers

Which of the following processes primarily involves macrophages removing erythrocytes?

Extravascular haemolysis Signup and view all the answers

What type of diagnostic finding may indicate monocytes have phagocytosed erythrocytes?

Presence of monocytes in blood smears Signup and view all the answers

Which pathway primarily contributes to generating NADPH in erythrocytes?

Pentose Phosphate-shunt (PP-S). Signup and view all the answers

What is a hallmark feature of erythrocytes affected by immune-mediated hemolytic anemia (IMHA)?

Presence of spherocytes Signup and view all the answers

What is the primary function of glucose in the metabolism of erythrocytes?

A significant portion is diverted to produce NADPH via the PP-S pathway. Signup and view all the answers

What physiological change occurs to erythrocytes during extravascular haemolysis?

Erythrocytes become dense and lack central pallor Signup and view all the answers

Why do dog and cat erythrocytes have low potassium levels?

They do not have sodium-potassium-ATPase. Signup and view all the answers

What happens to oxidized glutathione in the presence of NADPH?

It is reduced back to its active form. Signup and view all the answers

What happens to hemoglobin during intravascular haemolysis?

It is released into the plasma Signup and view all the answers

What mechanism leads to the formation of spherocytes in IMHA?

Partial phagocytosis and resealing of the membrane Signup and view all the answers

Which protein acts similarly to myosin in muscle tissue within erythrocytes?

Actin. Signup and view all the answers

What mediates the transport of unconjugated bilirubin from the spleen to the liver after erythrocyte destruction?

Albumin Signup and view all the answers

What is the underlying mechanism of intravascular hemolysis when RBCs are destroyed due to antibody attachment?

Extravascular water leaking into red cell cytoplasm Signup and view all the answers

Which antibody type is more efficient at complement fixation in cases of immune-mediated hemolytic anemia (IMHA)?

IgM Signup and view all the answers

What role do Fc-receptors play in the destruction of red blood cells by the mononuclear phagocytic system?

They facilitate binding of antibodies to RBCs Signup and view all the answers

What is a possible outcome when antibodies are directed against red cell precursors in the bone marrow?

Haemolytic anemia with a poor regenerative response Signup and view all the answers

Which condition is characterized by the absence or reduction of all stages of red cell precursors in the bone marrow?

Pure red cell aplasia Signup and view all the answers

In cases of significant RBC clumping due to high levels of antibodies, what effect does this have on hemolysis?

It facilitates RBC removal by the MPS Signup and view all the answers

Which breed characteristic is noted regarding the presentation of primary immune-mediated hemolytic anemia (IMHA)?

More frequently observed in middle-aged dogs Signup and view all the answers

What typically accompanies the presence of immune-mediated hemolytic anemia in affected patients?

Increased numbers of nucleated erythrocytes Signup and view all the answers

What is neonatal isoerythrolysis primarily caused by in newborn foals and kittens?

Maternal allo-antibodies against specific blood group antigens Signup and view all the answers

Why is neonatal isoerythrolysis more common in cats when a type B queen mates with a type A tom?

Type B cats have high anti-A titres Signup and view all the answers

What is a common clinical finding in a newborn affected by neonatal isoerythrolysis?

Anemia and icterus Signup and view all the answers

Which of the following statements about allo-antibody production in mares is true?

Production can persist for years after being sensitized Signup and view all the answers

How do newborn foals and kittens acquire allo-antibodies?

By absorbing colostrum shortly after birth Signup and view all the answers

What is the reported prevalence of neonatal isoerythrolysis in Standardbred horses?

2% Signup and view all the answers

Which characteristic of maternal allo-antibodies in cats distinguishes them from those in horses?

They are fully developed before birth Signup and view all the answers

What is the age at which donors should be assessed for health when donating blood in cats?

Up to 9 years old Signup and view all the answers

Study Notes

Haematology 410

Haematology is the study of the haematopoietic system, including the erythron (red blood cells), leukon (white blood cells), and haemostasis (blood clotting).
Blood consists of plasma, red blood cells, white blood cells, and platelets.
The haematopoietic system is a complex "organ" that includes bone marrow, lymphoid organs, and in some cases the liver.
It is involved in transport, host defense, and homeostasis throughout the body.
The Erythron includes circulating red blood cells, erythroid precursors, and stem cells in the bone marrow. Its primary function is oxygen transport.
The Leukon relates to the total number of white blood cells, which function as the body's defense mechanism.
Haemostasis is the interaction of blood vessels, platelets, and clotting factors to form and dissolve clots as needed.

Erythrocyte Maturation

Red blood cells develop from pluripotent stem cells in a multi-step process within the bone marrow.
Different stages of erythroid development have specific names and features.
The meta-rubricyte stage is the last nucleated stage before the reticulocyte, displaying 75-80% of mature haemoglobin.
Erythroid precursors, like normoblasts, are used clinically in a simple way as a general classification.
Each stage's name is indicative of its characteristic features.
Reticulocytes, a critical early stage, are released from the bone marrow and enter the bloodstream to mature into fully functional red blood cells. The time taken from stimulus to mature reticulocyte is about 3 days.

Erythrocyte Membrane

The erythrocyte membrane has a bilayer phospholipid structure with cholesterol molecules.
The distribution of lipids and membrane proteins affects membrane fluidity and flexibility, influencing erythrocyte function.
Transmembrane proteins play various roles, including receptors, ion channels, and structural components.
Proteins like ankyrin, actin, and spectrin, interact with the membrane, and are calcium-activated, facilitating changes in membrane shape.
Several elements (e.g. sialic acid) on the membrane are important for understanding pathological aspects of the membrane.
Changes in the proportion of esterified cholesterol can influence membrane fluidity.

Erythrocyte Metabolism

Erythrocytes utilize large amounts of glucose via the Embden-Meyerhof pathway, but also use the Pentose Phosphate Shunt to generate NADPH for antioxidant defense.
The erythrocyte's lifespan varies across species, with dogs having an average of 110 days and cats 70 days.
Senescent red blood cells are typically removed by the spleen.
The process of erythrocyte removal from circulation involves the breakdown of haemoglobin to its constituents (iron, amino acids, etc), which are recycled by the body.

Pathophysiology of Erythrocytes

Anaemia and Hypochromia: factors affecting erythrocyte production and maturation can result in significant red blood cell abnormalities and anaemia.
Diseases that affect circulation, like those found in the vascular pathology, can affect red blood cell function and structure.
Certain diseases, such as inflammatory disorders and infections, impact iron recycling, affecting red blood cell production by influencing the erythron.
Diseases influencing the lipid profile, including those affecting the liver, can impact the erythrocyte membrane.

Methods in Haematology

Sample collection, using appropriate anticoagulants, such as EDTA, heparin, citrate, fluoride, is crucial for preserving cellular elements and metabolites.
Different collection sites (e.g., capillary, venous) have advantages and disadvantages.
Various staining techniques, such as Romanowsky stains, allow for visualization and assessment of various cell components.
Counting of cells (and derived structures, e.g. reticulocytes) can be done manually (with haemocytometers) or automatically.
Assessment of red blood cell indices and counts, alongside examination of blood smears, is a critical part of haematologic analysis.

### Blood Transfusion

Blood transfusions can be life-saving in acute and chronic cases of anaemia related to various diseases.
Both the donor and recipient must be cross-matched and compatible prior to the blood transfusion.
Administration of blood must be kept sterile and done carefully.
Adverse reactions to transfusions can be immunologic (e.g. haemolysis) or non-immunologic (e.g. circulatory overload or hypothermia).
Appropriate monitoring of the patient post transfusion is crucial.

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Description

Test your knowledge on the intricate processes involved in iron transport and metabolism. This quiz covers the roles of plasmapheresis, vitamin requirements, and the internalization mechanisms of the transferrin-iron complex in normoblasts. Challenge yourself and understand the biochemical aspects of iron transport better.