Red Blood Cells Flashcards
What are red blood cells also known as?
Erythrocytes
What are the key characteristics of RBCs?
- The most abundant cells in blood.
- Constantly produced, with a lifespan of 1-4 months (depending on species).
- Main function is oxygen (O₂) transport.
- The first cells affected during chemotherapy, leading to anemia.
What is haemoglobin?
A protein tetramer (2 alpha, 2 beta chains) responsible for oxygen transport
What does haemoglobin contain that allows oxygen binding?
Iron-containing haem co-factors
How does fetal haemoglobin differ from adult haemoglobin in some mammals?
- In humans and sheep, fetal haemoglobin has 2 alpha and 2 gamma (γ) chains.
- It has a higher affinity for oxygen.
Which species do not have fetal haemoglobin with gamma chains?
Chickens, guinea pigs, rabbits, horses, pigs, dogs, and cats
What is Carbaminohemoglobin?
- A form of haemoglobin bound to carbon dioxide (CO₂).
- Formed when CO₂ levels are high in tissues.
How is CO₂ transported in the blood?
- Dissolved in blood plasma.
- Bound to haemoglobin.
- Converted into bicarbonate (HCO₃⁻).
What is erythropoiesis?
The process of RBC production in the bone marrow.
What is the origin of RBCs?
They originate from hemocytoblasts (stem cells) in the bone marrow
How do mammalian RBCs develop?
- Immature RBCs contain a nucleus.
- The nucleus is lost as RBCs mature (except in birds, reptiles, and amphibians)
What are reticulocytes, and why are they important?
- Immature RBCs without a nucleus.
- Critical indicator of bone marrow function
How does RBC maturation differ in horses?
- Horses do not have circulating reticulocytes.
- This makes RBC analysis difficult for diagnosing anemia.
What triggers erythropoiesis?
- Low oxygen (O₂) levels in the body.
- Detected by the kidneys, which release erythropoietin (EPO).
- EPO stimulates the bone marrow to produce RBCs.
What happens when the kidneys fail (e.g., in cats and humans)?
- Reduced erythropoietin production.
- Leads to lower RBC count → requiring EPO supplements.
What are the key characteristics of mature RBCs?
- Lack a nucleus and organelles.
- Contain ATP, nitric oxide, proteins, and sugars.
- Different species have different blood types.
What is the ABO blood system, and where is it found?
A blood type classification system found in humans
What is the most common symptom of RBC disorders?
Anemia (low RBC count)
What is a rarer RBC-related disorder?
Polycythemia (thickened blood due to high RBC numbers)
What are the three main causes of anemia?
- Loss of RBCs (e.g., internal bleeding).
- Destruction of RBCs (e.g., infection like malaria).
- Lack of RBC production (e.g., iron or vitamin B12 deficiency).
What is immune-mediated hemolytic anemia (IMHA)?
- An autoimmune disease where the body attacks its own RBCs.
- Caused by Type II hypersensitivity.
What is Haemolytic disease of the newborn, and how does it occur?
- Occurs in horses and livestock when antibodies from the mother’s colostrum destroy newborn RBCs.
- Often results from incorrect blood transfusion or previous pregnancy exposure.
What are the symptoms of haemolytic disease of the newborn?
- Born healthy, but becomes weak after suckling.
- Jaundice, anemia, mucus membrane damage.
- Can lead to death.
What are the two clinical types of anemia?
- Regenerative anemia → Bone marrow responds, increasing reticulocytes.
- Non-regenerative anemia → Bone marrow does not respond adequately.
