IMMUNOLOGY

Detailed explanation-1: -foreign proteins that gain access to the body through cuts and scrapes through the digestive or circulatory systems, or through the urinary and reproductive systems are called. antigens.

Detailed explanation-2: -A macrophage is the first cell to recognize and engulf foreign substances (antigens). Macrophages break down these substances and present the smaller proteins to the T lymphocytes.

Detailed explanation-3: -Phagocytosis is an important process for nutrition in unicellular organisms, while in multicellular organisms it is found in specialized cells called phagocytes. Phagocytosis consists in recognition and ingestion of particles larger than 0.5 m into a plasma membrane derived vesicle, known as phagosome.

Detailed explanation-4: -Immunoglobulin G (IgG), found in tissue fluids and plasma, attacks viruses, bacteria, and toxins.

Detailed explanation-5: -There are blood capillaries and special lymph capillaries, called lacteals, in the center of each villus. The blood capillaries absorb most nutrients, but the fats and fat-soluble vitamins are absorbed by the lacteals. The lymph in the lacteals has a milky appearance due to its high fat content and is called chyle.