what is the watery part of blood

Blood Plasma: Composition and Function

The liquid component of blood, a complex solution containing a variety of substances essential for maintaining homeostasis and facilitating transport throughout the circulatory system.

Principal Components

  • Water: Consisting of approximately 90-92% of the total volume, it acts as the solvent for all other constituents.
  • Plasma Proteins: Represent about 7-8% and include albumins, globulins (alpha, beta, gamma), and fibrinogen. These proteins perform diverse roles such as maintaining osmotic pressure, transporting lipids and hormones, participating in immune responses, and facilitating blood clotting.
  • Electrolytes: Ions such as sodium, potassium, chloride, calcium, and bicarbonate are crucial for maintaining pH balance, nerve and muscle function, and osmotic pressure.
  • Nutrients: Glucose, amino acids, lipids, and vitamins are transported to cells for energy production, growth, and repair.
  • Waste Products: Metabolic byproducts such as urea, creatinine, bilirubin, and lactic acid are transported to excretory organs for removal.
  • Dissolved Gases: Oxygen and carbon dioxide are transported, playing a critical role in respiration. Nitrogen is also present.
  • Hormones: Chemical messengers that regulate various physiological processes.

Functions

  • Transport: Serves as the medium for transporting blood cells, nutrients, waste products, hormones, and gases throughout the body.
  • Regulation of Blood Volume and Pressure: Plasma proteins, especially albumin, contribute to maintaining osmotic pressure, which influences fluid balance between the blood and tissues.
  • Immune Defense: Antibodies (immunoglobulins) present in the liquid portion of blood play a critical role in recognizing and neutralizing pathogens.
  • Blood Clotting: Contains clotting factors, such as fibrinogen, which are essential for forming blood clots and preventing excessive bleeding.
  • Temperature Regulation: Facilitates heat distribution throughout the body, helping to maintain a stable internal temperature.
  • Maintaining pH Balance: Acts as a buffer system, helping to maintain a stable pH in the blood.

Relationship to Serum

Serum is the fluid component of blood after coagulation. It is essentially the same as the liquid fraction of blood, but it lacks the clotting factors (e.g., fibrinogen) that are consumed during the clotting process.