Blood Components

Blood Components

Overview of Blood Composition

• Blood is made up of cells suspended in a thick liquid called plasma.

• Composition:

  • Approximately 45% of blood volume consists of:

    • Red Blood Cells (RBCs)

    • Leukocytes (white blood cells)

    • Platelets

Erythrocytes (Red Blood Cells)

• Main function: Transport oxygen (O2).

• Approximate number in the body: ~ 25 trillion.

• Structural features:

  • Biconcave shape: Increases surface area for O2 transport.

  • Lack of nucleus and mitochondria: Maximizes space for hemoglobin.

  • Each hemoglobin molecule can bind up to four O2 molecules.

Plasma

Composition and Functions of Plasma

• Plasma constitutes about 55% of blood volume.

• Contains:

  • Water: Acts as a solvent.

  • Electrolytes (ions): Maintain osmotic balance and pH buffering.

  • Proteins: Essential for various functions such as immunity and clotting.

Cellular Elements in Plasma

• Major cell types in blood include:

  • Leukocytes (5,000-10,000 per mm³ of blood)

    • Functions: Defense and immunity.

  • Erythrocytes (5,000,000-6,000,000 per mm³ of blood)

    • Function: Transport oxygen and some CO2.

  • Platelets (250,000-400,000)

    • Function: Blood clotting.

Plasma Proteins

• Albumin: Provides osmotic balance and pH buffering.

• Immunoglobulins: Functions as antibodies in defense.

• Fibrinogen: Involved in the clotting process.

• Apolipoproteins: Assist in lipid transport.

Coagulation Process

Initiation of Clotting

• Platelets play a crucial role in clotting:

  • Release clotting factors that trigger a cascade of reactions.

• Conversion process:

  • Prothrombin (inactive) is converted to thrombin (active).

  • Thrombin converts fibrinogen to fibrin, forming the structural framework of a blood clot.

Positive Feedback Mechanism

• The clotting process is enhanced by a positive feedback system, amplifying the response until a stable clot is formed.

Clotting Disorders

Genetic Mutations and Disorders

• Mutations in genes coding for clotting factors can lead to disorders such as hemophilia.

• Anti-clotting factors present in plasma prevent spontaneous clots.

• Issues arise when clots form incorrectly, leading to blockages (thrombus).

Consequences of Clotting

Medical Conditions Related to Clotting

• Myocardial Infarction (Heart Attack): Clots in coronary arteries can damage heart tissue due to oxygen deprivation.

• Pulmonary Embolism: Clots in the lungs restrict blood flow, causing potential death of lung tissue.

• Stroke: Occurs when clots obstruct blood flow to the brain, leading to oxygen deprivation.

  • Treatment options include CPR and TPA (tissue plasminogen activator) to dissolve clots.

Anticoagulants and Their Use

Blood Thinners

• Heparin, Warfarin, Coumadin: Anti-coagulants that help prevent clot formation but do not dissolve existing clots.

• NSAIDs (Aspirin, Ibuprofen, Naproxen): Prevent platelet clumping but may increase bleeding risk.

  • Care should be taken when combining NSAIDs and blood thinners.

Cholesterol and Cardiovascular Health

Understanding LDL and HDL

• Atherosclerosis: The build-up of fatty deposits (mostly cholesterol) in arteries, leading to hardening and narrowing of blood vessels.

• LDL (Low-Density Lipoprotein): Transports cholesterol to cells; high levels increase cardiovascular risk.

• HDL (High-Density Lipoprotein): Removes excess cholesterol and returns it to the liver; beneficial in reducing risk.

Inflammatory Response in Arterial Damage

• Damaged arteries trigger inflammation, with leukocytes responding and binding to lipids, thus forming plaques.

Treatment and Prevention of Atherosclerosis

Therapies and Interventions

• Treatments include:

  • Anti-inflammatory drugs (e.g., low-dose aspirin prevents platelet aggregation).

  • Statins: Lower LDL cholesterol levels to mitigate atherosclerosis risk.

  • Management of chronic hypertension to prevent arterial damage and plaque formation.