Hemoglobin and Blood Cell Functions Quiz

Chapter 19: The Cardiovascular System - The Blood

• This chapter covers the composition of blood, various cell types, red blood cell life cycles, hemoglobin, coagulation, and how blood is made.

About This Chapter

• Blood composition, cell types, and their origins, roles
• Red blood cell (RBC) life cycle, hemoglobin
• Blood coagulation mechanisms

Blood Composition

• Blood is composed of:
  • Plasma (55%): mostly water, proteins, electrolytes, nutrients, and waste products
  • Formed elements (45%): red blood cells (erythrocytes), white blood cells (leukocytes), and platelets
• Hematocrit measures the percentage of formed elements in whole blood.

Components of Blood

• Whole blood: 8% other fluids and tissues, 92% other fluids and tissues
• Blood plasma: 55%
  • Proteins: Albumins (54%), Globulins (38%), and Fibrinogen (7%)
  • Other solutes (1.5%): Electrolytes, nutrients, waste products, gases, regulatory substances, and vitamins
• Formed Elements (45%):
  • Platelets (150,000-400,000 per µL): Involved in clotting
  • White blood cells (leukocytes) (5,000-10,000 per µL): Types include- Neutrophils (60-70%), Lymphocytes (20-25%), Monocytes (3-8%), Eosinophils (2-4%), and Basophils (0.5-1%).
  • Red blood cells (erythrocytes) (4.8-5.4 million per µL): Carry oxygen.

The Origin of Blood Cells

• Hematopoiesis: the process of blood cell formation.
• Embryonic Hematopoiesis occurs in yolk sac, liver, spleen, thymus, lymph nodes, and red bone marrow.
• Adult Hematopoiesis occurs only in red bone marrow of flat bones and ends of long bones.
• Stem cells are the starting point and various types of blood cells develop from them.

Characteristics of Red Blood Cells

• Erythrocytes:
  • Biconcave discs.
  • Hemoglobin: Oxyhemoglobin (oxygen-carrying form) and Deoxyhemoglobin (oxygen-released form).
  • No nuclei or mitochondria.
  • Able to squeeze through capillaries

Red Blood Cell Counts

• Normal RBC counts vary by sex and age
• Males: 4.6-6.2 million per cubic millimeter of blood
• Females: 4.2-5.4 million per cubic millimeter of blood
• Children: 4.5-5.1 million per cubic millimeter of blood
• RBC count reflects oxygen-carrying capacity.

Hematocrit

• The percentage of total blood volume occupied by red blood cells
• Normal female range: 38-46% (average 42%)
• Normal male range: 40-54% (average 46%)

Hemoglobin

• A protein with four polypeptide chains and heme groups.
• Each heme group contains iron that binds to oxygen reversibly.

Transport of O2, CO2 and Nitric Oxide

• Hemoglobin carries oxygen from lungs to tissues.
• Transports 23% of carbon dioxide.
• Involved in regulating blood pressure and flow.

RBC Life Cycle

• RBCs circulate for 120 days
• Breakdown products are recycled, including the heme group, iron, and globin.

Red Blood Cell Production and Its Control

• Low blood oxygen stimulates the release of erythropoietin (EPO) from kidneys and liver
• EPO stimulates red blood cell production in the bone marrow

Types of White Blood Cells

• Leukocytes (five types):
  • Granulocytes: Neutrophils, Eosinophils, Basophils
  • Agranulocytes: Lymphocytes, Monocytes

Neutrophils

• First to arrive at infections.
• Phagocytic (engulf and destroy foreign particles).
• 54%-62% of leukocytes.

Eosinophils

• Defend against parasitic worm infestations
• 1%-3% of leukocytes.
• Elevated in parasitic worm infections and allergic reactions.

Basophils

• Release histamine and heparin.
• Less than 1% of leukocytes.

Monocytes

• Largest of blood cells.
• Leave bloodstream to become macrophages.
• Phagocytize bacteria, dead cells, and debris.
• 3%-9% of leukocytes.

Lymphocytes

• T cells and B cells—essential for immunity.
• B cells produce antibodies
• 25%-33% of leukocytes.

White Blood Cell Counts

• Normal range: 5,000-10,000 per cubic millimeter of blood
• Leukopenia: Low WBC count (below 5,000)
• Leukocytosis: High WBC count (above 10,000)
• Differential WBC count shows percentages of different types.

Emigration

• WBCs leave blood vessels and enter tissues (emigration) through endothelium.
• Process is stimulated by factors released by microbes (chemotaxis).

Hemostasis

• Sequence of reactions to stop blood loss
• Methods: Vascular spasm, platelet plug formation, blood clotting

1-Blood Vessel Spasm

• Blood vessels constrict to reduce blood flow

2-Platelet Plug Formation

• Platelets adhere to damaged vessel walls and aggregate to form a plug.

3-Blood Clotting Pathways

• Complex cascade of reactions lead to the formation of fibrin threads that create a clot.

Role of Vitamin K in Clotting

• Fat-soluble vitamin needed for synthesis of some clotting factors.
• Essential for proper functioning of the coagulation cascade.
• Produced by bacteria in the large intestine

Fate of Blood Clots

• Fibrinolysis breaks down the clot as the vessel heals.
• Plasmin digests fibrin and related components.

Thrombosis and Embolism

• Thrombosis: formation of thrombus (blood clot) within an unbroken blood vessel.
• Stasis (slow blood flow) can contribute to thrombosis.
• Embolism: obstruction of a vessel by an embolus (blood clot, air bubble, or fat).
• Pulmonary embolism: embolus lodged in lung
• Aspirin reduces thromboxane A2 synthesis to reduce inappropriate clotting.

Blood Groups and Blood Types

• Blood type categorizes blood based on antigens on red blood cells.
• Matching blood types is essential for transfusions.

Hemolytic Disease of the Newborn

• Rh incompatibility between mother and fetus can lead to hemolytic disease if mother's body produces antibodies that attack the baby's red blood cells.

Universal Donors and Recipients

• Type O blood is a universal donor as there are no antigens on the red blood cells.
• Type AB blood is a universal recipient, there are no antibodies.

Test your knowledge on the functions of hemoglobin and various blood cell types. This quiz covers topics such as hematocrit levels, the role of different leukocytes, and the effects of specific blood conditions. Perfect for students of biology or medical sciences!