Blood Physiology Quiz

Questions and Answers

How does decreased oxygen delivery to the kidneys affect erythrocyte production?

It immediately destroys existing erythrocytes.

It increases erythropoietin secretion. (correct)

It decreases erythropoietin secretion.

It has no effect on erythrocyte production.

What is the role of iron in hemoglobin?

It stabilizes the globin chains.

It binds to oxygen molecules. (correct)

It assists in the destruction of old erythrocytes.

It enhances the elasticity of red blood cells.

What happens to old erythrocytes as they age?

They are rejuvenated by iron.

They produce more hemoglobin.

They become rigid and fragile. (correct)

They become more flexible.

Which of the following components of hemoglobin carries oxygen?

Iron in heme groups. Signup and view all the answers

What is hemoglobin concentration important for diagnosing?

Anemia. Signup and view all the answers

At what saline concentration does complete hemolysis occur?

< 0.35% Signup and view all the answers

Which condition is associated with increased osmotic fragility?

Hereditary spherocytosis Signup and view all the answers

What is the role of agglutinins in blood grouping?

To bind specific antigens on the RBC membrane Signup and view all the answers

According to Karl Landsteiner's Law, if antigen A is present on RBCs, what must be true about the plasma?

Antibody A must be absent Signup and view all the answers

What is the main reason for blood group typing?

To assess the presence of antigens on RBCs Signup and view all the answers

Study Notes

Oxygen Delivery and Erythropoiesis

Decreased oxygen delivery to kidneys boosts erythropoietin secretion, stimulating red blood cell (RBC) production.

Hemoglobin Structure and Function

Hemoglobin (Hb) reversibly binds oxygen, composed of four globin chains and four heme groups.
Each heme contains an iron atom capable of binding one O2 molecule; thus, one Hb can transport four O2 molecules.
In the lungs, hemoglobin forms oxyhemoglobin (bright red) upon oxygen binding; releases oxygen in tissues, becoming darker red deoxyhemoglobin (or reduced hemoglobin).

Erythrocyte Lifecycle

Erythrocytes live 100–120 days; aging cells become rigid and fragile, leading to their breakdown.
Macrophages engulf dying erythrocytes, separating hemoglobin into heme (converted to iron and bilirubin) and globin (reusable protein).

Importance of Hemoglobin Concentration

Hemoglobin concentration is critical for diagnosing anemia and varies with age, gender, and altitude.
Normal hemolysis occurs at saline concentrations of 0.50 – 0.55%; 50% lysis at 0.40% - 0.45%; complete lysis below 0.35%.

Osmotic Fragility Test (OFT)

Increased osmotic fragility indicates hereditary spherocytosis; decreased fragility suggests conditions like thalassemia, sickle cell anemia, and iron deficiency anemia.

Human Blood Groups

Blood type determination relies on surface antigens (agglutinogens) and the corresponding antibodies (agglutinins) present in plasma.
Major blood groups include the ABO system and the Rh system.

ABO Blood Typing

ABO blood types are determined by the presence of A and B antigens on RBCs.
Karl Landsteiner's Law dictates the compatibility of antigens and antibodies:
- Type A: A antigen, anti-B antibody
- Type B: B antigen, anti-A antibody
- Type AB: A and B antigens, no antibodies
- Type O: No antigens, anti-A and anti-B antibodies

Clinical Significance of Blood Groups

Vital for safe blood transfusion, managing hemolytic disease of the newborn, paternity disputes, and assessing susceptibility to diseases.

Rh Factor Implications

The Rh blood group is characterized by the presence of the D antigen; individuals are Rh+ or Rh-.
Anti-D antibodies form only after exposure to Rh+ blood in Rh- individuals.

Erythroblastosis Fetalis

Occurs when an Rh- mother’s antibodies attack the RBCs of an Rh+ fetus, triggered by previous Rh+ exposure.
Requires careful cross-matching of blood for transfusions and must be confirmed prior to transfusions in Rh- individuals.

Leukocytes (WBCs)

WBCs are integral to the immune system, combating pathogens, damaged cells, and foreign substances.
Produced in bone marrow; mature in lymphatic organs; are complete cells with nuclei and organelles.

WBC Count and Functions

Normal WBC count: 4,000-11,000 cells/mm³, average around 7,000 cells/mm³.
Decreased count (leukopenia) may arise from diseases; increased count (leukocytosis) reflects infection or inflammation.

Immune Response

WBCs perform phagocytosis and antibody production to neutralize pathogens and recruit additional immune cells.

Blood Coagulation Mechanisms

Coagulation involves over 50 components balancing procoagulants and anticoagulants; ensures controlled clotting following vascular injury.
Clotting factors are numbered I-XIII, synthesized primarily in the liver, and require vitamin K for production of certain factors.

Coagulation Pathways

Coagulation includes intrinsic (slower, initiated by tissue damage) and extrinsic pathways, merging into a common pathway for effective clot formation.

Description

This quiz covers key concepts in blood physiology, focusing on oxygen delivery and erythrocyte production. It explores the role of erythropoietin and details the structure and function of hemoglobin. Test your knowledge on these fundamental aspects of blood and its importance in the body.