Recording-2025-03-05T01:55:29.862Z

Components of Blood

• Whole Blood: Blood is considered whole when drawn from the body; it separates into components when spun.

Plasma

• Appearance: Amber-colored liquid that rises to the top after centrifugation.

• Composition:

  • Water: Major component of plasma.

  • Proteins: Includes albumin, immunoglobulins, and transport proteins.

    • Albumin: Maintains osmotic pressure, keeps fluid in blood vessels, synthesized by the liver.

    • Immunoglobulins: Antibodies such as IgG and IgA, crucial for immune response.

  • Solutes: Electrolytes, nutrients, and waste products dissolved in plasma.

• Percentage of Blood: Plasma makes up about 55% of whole blood.

Formed Elements

• Definition: Cellular components that settle at the bottom when blood is spun.

• Main Types:

  • Red Blood Cells (RBCs) / Erythrocytes:

    • Appearance: Red due to hemoglobin.

    • Function: Transport oxygen and carbon dioxide; live approximately 120 days.

    • Shape: Biconcave for flexibility; lack a nucleus, thus don’t undergo mitosis.

  • White Blood Cells (WBCs) / Leukocytes:

    • Located in a "buffy coat" layer between plasma and RBCs; less dense than RBCs.

  • Platelets / Thrombocytes:

    • Cell fragments involved in clotting, central for wound healing.

Differentiation Between Plasma and Formed Elements

• Plasma: Fluid with dissolved substances, includes proteins, and does not contain cells.

• Formed Elements: Composed of fully formed cells and cell fragments (like platelets).

Blood Types

• Naming Conventions:

  • Platelets (thrombocytes), White Blood Cells (leukocytes), Red Blood Cells (erythrocytes).

• Oxygen Content:

  • Arterial Blood: Bright red due to high oxygen levels.

  • Venous Blood: Darker; lower oxygen content.

Plasma Proteins and Their Roles

• Albumin: Major protein, important for maintaining osmotic pressure.

• Antibodies: Protect the body from pathogens, part of the immune response.

• Transport Proteins: Carry molecules like hormones in the blood.

Blood Cell Lifespan and Function

• Red Blood Cells:

  • Lifespan: ~120 days, recycled by the spleen.

  • Hemoglobin: Each molecule can carry 4 oxygen molecules.

• Platelets:

  • Role: Blood clotting; become sticky upon vessel injury, release chemicals to recruit more platelets.

• White Blood Cells:

  • Subtypes:

    • Neutrophils: Most abundant, respond to bacterial/fungal infections.

    • Eosinophils: Fight parasites and engage in allergic reactions.

    • Basophils: Release histamines and heparin during allergic responses.

    • Lymphocytes: Involved in adaptive immunity (B cells, T cells, and natural killer cells).

  • Phagocytosis: Engulf and digest foreign materials.

Blood Vessels

• Layers of Blood Vessels:

  • Tunica Intima: Innermost layer, smooth to ensure efficient blood flow.

  • Tunica Media: Middle muscular layer, regulates blood vessel diameter.

    • Importance in arteries: Allows adjusting to high pressure, providing elasticity.

  • Tunica Externa: Outer connective tissue layer for protection.

• Types of Blood Vessels:

  • Arteries: Carry blood away from the heart, have thick media to withstand high pressure.

  • Veins: Carry blood to the heart, contain valves to prevent backflow, often less thick than arteries.

  • Capillaries: Single layer of endothelial cells for exchange of gases and nutrients.

Circulatory Pathways

• Circle of Willis: Ensures brain receives adequate blood supply even if a blockage occurs.

• Hepatic Portal Circulation:

  • Connects capillary beds in the intestines to the liver for nutrient processing before entering systemic circulation.

• Fetal Circulation:

  • Umbilical Vein: Carries oxygenated blood to the fetus.

  • Umbilical Arteries: Carry deoxygenated blood from the fetus back to the placenta.

Blood Pressure and Pulse

• Normal Blood Pressure: Approximately 120/80 mmHg.

  • Systolic Pressure: Pressure during heart contraction.

  • Diastolic Pressure: Pressure during heart relaxation.

• Pulse Sites: Important for clinical assessments of circulation.