Question

By what name is the liquid medium of blood known as?
a. Plasma
b. Blood corpuscles
c. Waste (excretory) substances
d. Waste material

Answer 1

Hint: Blood consists of two components, the cellular components and the fluid component. The fluid component is called the plasma which is 90% water with various substances dissolved or suspended in it, like nutrients, proteins, wastes, ions and cellular components.

Complete answer:
Blood is a fluid connective tissue. Like all other connective tissues, it is made up of cellular elements and an extracellular matrix. The cellular elements include red blood cells (RBCs), white blood cells (WBCs) and platelets. The extracellular matrix, called plasma, makes blood unique among all connective tissues as it is fluid. Plasma is a straw coloured liquid portion of the blood which is composed of water, salts, enzymes, antibodies and other proteins. In human blood, cellular components make up approximately 45 percent of the blood and the liquid plasma 55 percent.

Among the given options:
Blood corpuscles account for 45% of the blood tissue by volume. These are classified as erythrocytes, leukocytes and thrombocytes. Erythrocytes are commonly referred to as red blood cells or RBCs. Leukocytes are white blood cells, or WBCs. A smaller third cellular constituent are the thrombocytes (platelets).

The major excretory wastes produced in the body are carbon dioxide, excess water and nitrogenous compounds like ammonia, urea and uric acid.

Waste materials are unwanted or unusable substances which are discarded after primary use, or are worthless and of no use.

Hence, The correct answer is option (A).

Additional information:
Plasma serves as a transport medium for delivering nutrients to the cells of the various organs of the body. It also helps in transporting waste products derived from cellular metabolism to the kidneys, lungs and liver for excretion.
Plasma is considered as a transport system for blood cells, and it plays a crucial role in maintaining normal blood pressure. It also takes part in distribution of heat throughout the body and thus maintains homeostasis, or biological stability.

Note: Plasma serves as the liquid base for whole blood. Whole blood minus RBCs (erythrocytes or red blood cells), WBCs (leukocytes or white blood cells) and platelets (thrombocytes) make up the plasma.