(1) Hematopoietic System

Overview of the Hematopoietic System

• The hematopoietic system includes blood, a connective tissue consisting of:

  • Liquid matrix: Plasma, which makes up more than 55% of total blood volume.

  • Formed elements: Cells and cell fragments, comprising 45% of total blood volume.

Blood Volume in Adults

• Average adult female: 4 to 5 liters.

• Average adult male: 5 to 6 liters.

• Blood constitutes approximately 8% of total body weight.

Plasma Composition

• Plasma is a pale yellow fluid containing:

  • 91% Water

  • 7% Proteins

    • Albumins: The majority of plasma proteins.

    • Globulins: Include immune system components and transport molecules.

  • 2% Other components: Ions, nutrients, gases, and waste products.

Proteins in Plasma

• Albumin: Most abundant protein in plasma.

• Globulins: Functions include:

  • Immune response.

  • Transport molecules for other cells.

  • Presence of clotting factors such as fibrinogen.

• Fibrinogen: Converts to fibrin to form blood clots.

Serum

• Definition: Plasma without clotting factors (e.g., fibrinogen).

Formed Elements in Blood

• Comprised of:

  • Red Blood Cells (RBCs): Also known as erythrocytes; the most abundant formed elements (95%).

  • White Blood Cells: Other formed elements involved in immune response.

  • Platelets: Cell fragments important for clotting.