The correct option is 1, 2 and 3 only.
Explanation
Blood is a specialized connective tissue consisting of a fluid matrix known as plasma and formed elements. Plasma is a straw-coloured, viscous fluid that serves as the medium for transporting nutrients, hormones, and waste products.
Statement-wise Analysis:
- Statement 1 is Correct: Plasma constitutes nearly 55% of the total blood volume. The remaining 45% consists of formed elements (erythrocytes, leucocytes, and platelets).
- Statement 2 is Correct: Water is the primary constituent of plasma, accounting for approximately 90-92% of its volume. This high water content allows plasma to act as an effective solvent.
- Statement 3 is Correct: Proteins contribute around 6-8% of plasma. The major plasma proteins include fibrinogen (essential for clotting), globulins (involved in defense mechanisms), and albumins (crucial for maintaining osmotic balance).
- Statement 4 is Incorrect: Serum is defined as plasma without clotting factors. During coagulation, clotting factors like fibrinogen are utilized to form a clot. The fluid remaining after the removal of these factors is termed serum (Serum = Plasma - Clotting Factors).
Key Takeaway: The fundamental difference between plasma and serum is that plasma contains clotting factors (such as fibrinogen), whereas serum is the fluid obtained after blood has clotted and lacks these factors.