Human Blood Physiology Quiz

Questions and Answers

What role does the smoothness of the endothelial cell surface play in blood clot prevention?

It aids in the activation of clotting factors.

It prevents contact activation of the intrinsic clotting system. (correct)

It triggers the extrinsic clotting system.

It promotes the aggregation of platelets.

What is erythroblastosis fetalis primarily caused by?

Maternal antibodies destroying neonatal red blood cells. (correct)

Fetal intolerance to maternal blood cells.

Maternal antibodies attacking the fetal platelets.

Transfusion of incompatible blood types during pregnancy.

Which of the following statements about Rh blood groups is incorrect?

Rh factor was first discovered in Rhesus monkeys.

Rh positive indicates the presence of the Rh antigen.

Rh-positive individuals lack the Rh antigen. (correct)

Rh-negative individuals do not have the Rh antigen.

What is the expected outcome if a person with type A blood receives type B blood?

The blood will agglutinate due to antigen-antibody matching. Signup and view all the answers

What prevents thrombomodulin from exacerbating clot formation?

It inhibits thrombin and slows the clotting process. Signup and view all the answers

The presence of which blood group antigens can be detected in the human body?

At least 24 blood groups, including ABO and Rh. Signup and view all the answers

Which component is responsible for repelling clotting factors on the endothelial surface?

Glycocalyx. Signup and view all the answers

What factor might complicate pregnancies for Rh-negative mothers?

Isoimmunization against fetal Rh-positive antigens. Signup and view all the answers

What is the normal pH range of human blood?

7.35-7.45 Signup and view all the answers

Which component is present in the buffy coat in greater amounts after whole blood centrifugation?

WBCs Signup and view all the answers

Which statement about plasma is accurate?

Contains clotting factors Signup and view all the answers

What is the primary function of transferrin in the blood?

Delivery of ferric ions Signup and view all the answers

What does hematocrit measure?

Percentage of total blood volume occupied by RBCs Signup and view all the answers

What condition is characterized by an abnormally high number of RBCs?

Polycythemia Signup and view all the answers

What is the lifespan of platelets under normal conditions?

5-9 days Signup and view all the answers

Which of the following is NOT a phase of hemostasis?

Blood transfusion Signup and view all the answers

What role does thrombopoietin play in platelet production?

Promotes development of megakaryocyte colony-forming cells Signup and view all the answers

What happens to RBC production during hypoxia?

Increased RBC production Signup and view all the answers

What is the primary role of vascular constriction in hemostasis?

To prevent blood loss from the ruptured vessel Signup and view all the answers

Which factor is NOT involved in the activation of the clot formation process?

Oxygen Signup and view all the answers

What primarily triggers the extrinsic pathway of coagulation?

External trauma causing blood to escape Signup and view all the answers

What is necessary for platelet plug formation to be effective in stopping blood loss?

The damaged vessel opening is small Signup and view all the answers

Which statement correctly describes the differences between the intrinsic and extrinsic pathways?

The intrinsic pathway is slower and activated by internal factors Signup and view all the answers

What substances are crucial for platelet activation during hemostasis?

ADP, thromboxane A2, and serotonin Signup and view all the answers

What do both intrinsic and extrinsic pathways of coagulation have in common?

They both activate the same coagulation factors through different mechanisms Signup and view all the answers

What characterizes the rapid response of the extrinsic pathway?

It is quicker than the intrinsic pathway Signup and view all the answers

Study Notes

Human Blood pH

Normal pH of human blood is 7.35-7.45.

Buffy Coat Composition

The buffy coat contains a higher concentration of white blood cells (WBCs) after whole blood centrifugation.

Plasma Characteristics

Plasma consists of serum and clotting factors, and contains components necessary for blood clotting.

RBC Life Cycle

Ferritin stores iron intracellularly, releasing it in a controlled manner.
Transferrin is a glycoprotein in blood plasma responsible for iron transport to tissues.
Erythropoiesis is the production of red blood cells, starting from proerythroblasts in red bone marrow.
Proerythroblast divides and synthesizes hemoglobin, leading to reticulocyte formation, which eventually loses its nucleus.

Erythropoiesis Regulation

Erythropoiesis and RBC destruction are balanced; hypoxia triggers increased RBC production.

Hematocrit

Reflects the percentage of blood volume occupied by RBCs.
Normal hematocrit ranges: 38-46% for adult females, 40-54% for adult males.
Testosterone stimulates erythropoietin (EPO) synthesis, influencing RBC production.

Anemia and Polycythemia

Anemia is characterized by low hemoglobin levels, resulting from insufficient RBCs or hemoglobin.
Polycythemia involves an abnormally high RBC count, with hematocrit levels exceeding 65%, leading to increased blood viscosity and risks such as high blood pressure.

Platelet Formation

Platelets are small cell fragments that prevent bleeding, produced in bone marrow.
Thrombopoietin stimulates the differentiation of myeloid stem cells into megakaryocytes, which fragment into platelets (2000-3000 per cell).
Normal platelet count ranges from 150,000 to 400,000 per microliter of blood.

Hemostasis Process

Hemostasis involves a series of responses to stop bleeding, including vascular constriction and platelet plug formation.
Platelet aggregation occurs in response to blood vessel injury, requiring ADP and thromboxane A2 for activation.

Blood Coagulation

Coagulation is initiated by substances from damaged vascular walls and requires calcium ions.
Two pathways:
- Extrinsic pathway (external damage, quick response).
- Intrinsic pathway (internal trauma, platelet activation).

Blood Clotting Pathways

Both intrinsic and extrinsic pathways converge to form prothrombin activator, leading to a common coagulation pathway.

Blood Groups

Blood types are determined by agglutinogens (antigens) on RBC surfaces; significant blood groups include ABO and Rh.
Antibodies are produced in response to environmental carbohydrates, reaching peak levels by age 5-10.

Rh Factor and Compatibility

Rh blood group identifies Rh-positive and Rh-negative individuals; problems arise during Rh incompatibility in pregnancies.

Erythroblastosis Fetalis

A condition where maternal antibodies destroy fetal red blood cells, mainly affecting Rh-positive babies born to Rh-negative mothers.
Typically does not affect first pregnancies but can cause significant issues in subsequent ones; Coombs test can detect maternal antibodies.

Blood Transfusion Compatibility

Blood agglutination occurs when antibodies in the recipient's blood match antigens in the transfused blood, causing clumping (e.g., type A blood reacting to type B blood).

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Description

Test your knowledge on the physiological aspects of human blood, including its pH levels and the composition of blood components. This quiz will challenge your understanding of blood and plasma characteristics. Perfect for students in physiology and medical fields.