Human Biology: Immune System and Blood Cells

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Questions and Answers

What is a primary function of T cells in the immune response?

Mount immune response via antibodies

Phagocytosis

Develop into macrophages

Direct cell attack (correct)

What distinguishes leukocytes from erythrocytes in terms of life span?

Erythrocytes have a life span of days

Leukocytes live for hours to years (correct)

Erythrocytes live for months

Leukocytes have a life span of days to weeks

Which statement best explains the effect of chemotherapy on blood cells?

It disrupts the development of normal blood cells (correct)

It has no impact on normal fast-growing cells

It enhances the growth of leukocytes while killing cancerous cells

It selectively targets only leukocytes and leaves other cells unharmed

What is the main structural feature of erythrocytes that facilitates gas exchange?

Highly flexible biconcave disc shape Signup and view all the answers

Which type of white blood cell is primarily responsible for developing into macrophages?

Monocytes Signup and view all the answers

Which plasma protein is primarily responsible for maintaining osmotic pressure?

Albumin Signup and view all the answers

What is the primary function of γ globulins in the plasma?

Bind to foreign substances Signup and view all the answers

Which type of leukocyte is responsible for phagocytizing bacteria?

Neutrophils Signup and view all the answers

Which plasma protein is converted into a fibrin network for clot formation?

Fibrinogen Signup and view all the answers

What is the lifespan of eosinophils in the bloodstream?

8-12 days Signup and view all the answers

Which leukocyte lack obvious granules in their cytoplasm?

Agranulocytes Signup and view all the answers

What is the primary role of prothrombin in the body?

Blood clotting Signup and view all the answers

Which of the following is NOT a function of albumin?

Bind foreign substances Signup and view all the answers

Which blood group contains no agglutinins in the plasma?

Blood group AB Signup and view all the answers

What percentage of the population is estimated to be Rh-positive?

85% Signup and view all the answers

What is the first step in the hemostasis process?

Vasoconstriction of the injured blood vessel Signup and view all the answers

Which of the following substances is NOT a vasoconstrictor released during vascular spasms?

Histamine Signup and view all the answers

What complication can arise during a second pregnancy for an Rh-negative mother who did not receive Rhogam after her first delivery?

Erythroblastosis fetalis Signup and view all the answers

Which blood group has both A and B agglutinogen present on the red blood cells?

Blood group AB Signup and view all the answers

What is the primary purpose of hemostasis?

To prevent excessive blood loss Signup and view all the answers

Which of the following is NOT a step in the hemostasis process?

Vascular dilation Signup and view all the answers

What is the primary function of hemoglobin in red blood cells?

Transport of oxygen and carbon dioxide Signup and view all the answers

How many heme groups are present in a single hemoglobin molecule?

Four Signup and view all the answers

What is the life span of a red blood cell?

120 days Signup and view all the answers

Which protein chains are present in hemoglobin?

Two alpha and two beta chains Signup and view all the answers

What percentage of carbon dioxide in the blood is bound to the globin moiety?

5% Signup and view all the answers

Which of the following is a nonprotein component of hemoglobin responsible for binding oxygen?

Heme Signup and view all the answers

What is the typical red blood cell count range for females?

4.2-5.2 million cells/mm3 Signup and view all the answers

What is erythropoiesis?

Formation of red blood cells Signup and view all the answers

Which hormone is primarily responsible for stimulating erythropoiesis in response to decreased oxygen supply?

Erythropoietin Signup and view all the answers

Which nutrient is essential for hemoglobin synthesis?

Iron Signup and view all the answers

What is the primary site of erythropoiesis in adults?

Red bone marrow Signup and view all the answers

Which of the following conditions can lead to anemia?

Decrease in RBC count Signup and view all the answers

What role does Vitamin C play in erythropoiesis?

It enhances iron absorption Signup and view all the answers

What is a key characteristic of blood groups in the ABO system?

Presence of agglutinogens on RBCs Signup and view all the answers

The primary function of erythropoietin is to stimulate which of the following processes?

Stimulate RBC formation Signup and view all the answers

Which of the following nutrients plays a crucial role in RBC maturation and is predominantly found in red meat?

Cobalamin (Vitamin B12) Signup and view all the answers

What triggers the adherence of platelets to collagen during platelet plug formation?

von Willebrand factor Signup and view all the answers

Which of the following is a direct effect of thromboxane A2 on the vascular system?

Causes vasoconstriction Signup and view all the answers

What is the first step in the coagulation process after platelet plug formation?

Prothrombin activator is formed Signup and view all the answers

What is the primary role of plasmin in the context of hemostasis?

To dissolve fibrin in a formed clot Signup and view all the answers

Which anticoagulant is known to be extracted from animal sources?

Heparin Signup and view all the answers

What is the outcome of excess fibrinolysis in the vascular system?

Increased risk of bleeding Signup and view all the answers

Which vitamin's antagonists are utilized to decrease certain coagulation factors?

Vitamin K Signup and view all the answers

What is the role of tissue plasminogen activator (t-PA) in the process of fibrinolysis?

To convert plasminogen to plasmin Signup and view all the answers

Study Notes

Blood Physiology and Pathophysiology

Blood is a liquid connective tissue, approximately 8% of total body weight in a 70 kg man
Blood volume is roughly 5-6 liters in men and 4-5 liters in women
Blood is composed of plasma (55%) and formed elements (45%)
Plasma is primarily water (90%) with organic and inorganic components and dissolved gases
Formed elements include Erythrocytes (RBCs), Leukocytes (WBCs), and Thrombocytes (Platelets)

Objectives

Describe cellular and non-cellular components of blood
Recognize blood functions
Define erythropoiesis, leucopoiesis, and thrombopoiesis
Identify RBC formation sites at different developmental ages
Describe RBC maturation stages
Describe RBC maturation
Describe RBC production regulation in response to hypoxia and erythropoietin hormone secretion
Identify clinical conditions associated with high levels of erythropoietin in the blood

Components of Blood

Plasma: 55% by volume, containing water (91%), proteins (7%), and other solutes (2%)
Formed Elements: 45% by volume, including:
- Erythrocytes (RBCs): 4-6 million/µl (in males); 4-5 million/µl (in females)
- Leukocytes (WBCs): 4,000-11,000/µl
- Thrombocytes (Platelets): 150,000-400,000/µl

Blood Composition and Hematocrit

Hematocrit: percentage of RBCs in whole blood. (Normal values vary by sex due to hormonal influences)

Functions of Blood

Transport: Gases, nutrients, hormones, waste products
Regulation: Acid-base balance, blood pressure
Defense: Against infection through white blood cells and the immune system. Hemostasis (blood clotting)

The Plasma

Plasma constitutes 55% of blood volume
Plasma is a yellow, clear fluid
On standing, it clots. The remaining fluid is called serum.
Serum is the plasma from which the clotting elements have been removed
Composed of 90% water, 9% organic constituents, and inorganic constituents and blood gases

Plasma Proteins

Albumin: Major contributor to plasma osmotic pressure, transport of various molecules; found in the liver (50% in the liver and 50% in lymphocytes)
Globulins: Transport hormones and fat-soluble vitamins; produced by liver and other cells (50% in the liver and 50% in lymphocytes)
Fibrinogen: Essential in blood clotting; produced by the liver
Prothrombin: Essential in blood clotting; produced by the liver

Specific Functions of Plasma Proteins

Albumin: Maintains osmotic pressure, transports hormones and ions
Globulins: Transport hormones, fat-soluble vitamins; antibodies (gamma globulins) bind foreign substances
Fibrinogen: Converted into fibrin to form blood clots
Prothrombin: Involved in blood clotting

Leukocytes (White Blood Cells)

4,000–11,000/µl
Two major categories:
- Granulocytes: Contain membrane-bound granules (e.g., neutrophils, eosinophils, basophils)
- Agranulocytes: Lack visible granules (e.g., lymphocytes, monocytes)

Erythrocytes (Red Blood Cells)

Average: 5 million/mm³
Appearance: Biconcave disc shape (for gas exchange, flexibility)
Structure: Primarily hemoglobin (oxygen and carbon dioxide transport); no nucleus or mitochondria
Functions: Carry hemoglobin, transport oxygen, transport carbon dioxide, buffer pH
Life Span: 120 days
Fate: Removed and broken down in the spleen

Erythropoiesis

Process of RBC formation
Intrauterine: Liver and spleen
Postnatal (children): Predominantly red bone marrow of axial and appendicular skeletons
Adults: Red bone marrow of axial skeleton

Factors Regulating Erythropoiesis

Decreased oxygen supply (hypoxia) to tissues stimulates erythropoietin (EPO) production
EPO is mainly produced by kidneys (85%) and liver (15%)
EPO stimulates RBC formation

Role of Nutrients for Erythropoiesis

Cobalamin (B12): RBC maturation (liver)
Folic Acid: RBC maturation (leaves, fish)
Vitamin B6: Hemoglobin synthesis (eggs, whole grains, potatoes)
Amino Acids: Nucleoprotein synthesis (eggs, meat, milk)
Vitamin C: Conversion of folic acid to active forms (aids absorption)
Iron: Essential for hemoglobin synthesis

Factors Affecting Erythropoiesis

Hormones: Testosterone stimulates EPO secretion, thyroid hormones increase cell metabolism, cortisol increases RBC formation
Healthy liver: Necessary for globin, iron, and vitamin B12 storage, EPO production
Healthy bone marrow: Site of erythropoiesis, vulnerable to irradiation and tumors

Anemias

Decrease in red blood cells (RBCs), hemoglobin (Hb), or both
Leads to decreased oxygen supply to tissues
Categorized (based on morphology and underlying causes)

Blood Groups

ABO System: Based on presence or absence of A or B antigens on RBCs. Plasma contains corresponding antibodies (Anti-A, Anti-B) , which can agglutinate foreign RBCs.
Rh System: Based on the presence or absence of antigen D (Rh factor)
- Rh+ve: Present
- Rh-ve: Absent
Important in blood transfusions and pregnancies (involving Rh-incompatibility between the mother and child

Hemostasis

Hemostasis: The process of stopping bleeding
steps in hemostasis:
1. vascular spasm (vasoconstriction of injured vessel)
2. platelet plug formation
3. coagulation (formation of blood clot)
4. fibrinolysis (dissolving of blood clot)

Anticoagulants

Heparin, Warfarin, and other agents to prevent clotting

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Description

Test your knowledge of the immune system and blood cell functions with this quiz! Covering topics such as T cells, leukocytes, erythrocytes, and plasma proteins, this quiz will challenge your understanding of key biological principles related to human anatomy and physiology.