Blood Componests

Blood and Its Components

Introduction

• Overview of blood and the lymphatic system.

Blood Components

• Whole blood components:

  • Red Blood Cells (Erythrocytes)

  • White Blood Cells (Leukocytes)

  • Platelets

  • Plasma: Water, proteins, antibodies, sodium, chloride, glucose, urea; transports substances.

Separation of Blood Components

• Centrifugation separates blood by mass:

  • Plasma: Top (yellowish liquid).

  • Buffy Coat: Thin white layer (WBCs and platelets).

  • Red Blood Cells: Heaviest, at the bottom (red).

Blood Volume

• Average adult: approximately $5$ liters of blood.

Plasma

• Liquid portion of blood, mostly water ($90$% of plasma volume).

• Contains critical proteins: clotting factors, transport proteins, antibodies.

• Assists in bodily functions and blood test measurements.

Formed Elements of Blood

• Cell components, nearly half of total blood volume.

• Red Blood Cells (Erythrocytes):

  • Contain hemoglobin for oxygen transport.

  • Hematocrit: Ratio of red blood cell volume to total blood volume; normal is around $40$

  • Low hematocrit indicates anemia; high indicates polycythemia.

• White Blood Cells (Leukocytes):

  • Immune cells (e.g., lymphocytes, eosinophils).

  • Roughly $5,000$ to $10,000$ WBCs per milliliter of blood.

• Platelets:

  • Important for blood clotting.

  • Approximately $250,000$ platelets per milliliter.

Blood Disorders

• Anemia: Reduced oxygen-carrying capacity (e.g., Iron Deficiency, Pernicious, Sickle Cell).

• Polycythemia: Excessive red blood cell production, increased hematocrit (can result from blood doping).

• Leukemia: Cancer charactized by overproduction of abnormal white blood cells.

The Lymphatic System

• Components: Lymphatic Vessels, Lymph Nodes, Thymus Gland, Spleen.

Functions of the Lymphatic System

• Drains excess interstitial fluid.

• Assists in dietary fat absorption.

• Pivotal role in immune response (houses white blood cells).

Interaction with the Circulatory System

• Lymph fluid returns to circulatory system via subclavian vein.

• Helps maintain fluid homeostasis.

Blood Cell Formation

• Stem Cells (common precursors):

  • Myeloid Stem Cells: Give rise to red blood cells, platelets, various white blood cells.

  • Lymphoid Stem Cells: Lead to T-cells, B-cells, and plasma cells.

  • Cells differentiate under specific signals.

Blood Donation

• Average donation: approximately $500$ mL.

• Benefits: saves lives, safe procedure.

• Different blood groups (O positive, O negative, A positive, etc.) determine transfusion compatibility.