NDA (II) 2022 General Ability Test · Question 79 of 150

Correct — D, plasma. Lymph is formed when part of the blood plasma filters out of the blood capillaries into the spaces between cells, so it is essentially plasma that has left the blood vessels. It is the same watery, straw-coloured, salt-and-glucose-carrying fluid, but with much less protein, because the large plasma proteins mostly stay behind in the capillary. Lymph carries white blood cells, especially lymphocytes, and no red blood cells, and is eventually returned to the blood circulation.

• (a)digestive juice — Digestive juices are enzyme-rich secretions poured by glands into the cavity of the gut to break food down. Lymph is a circulating body fluid in the tissue spaces, not a glandular secretion.
• (b)cytoplasmic fluid — Cytoplasm lies inside the cell membrane. The question itself says lymph occupies intercellular spaces — it is extracellular by definition, so it cannot resemble the fluid inside a cell.
• (c)urine — Urine is the waste filtrate produced by the kidneys for excretion and is loaded with urea and excess salts. Lymph is neither a waste product nor a kidney product; it goes back into the blood rather than out of the body.

Blood pressure in the capillaries pushes part of the plasma, minus most of its large proteins and all its red cells, out into the spaces between cells. This is tissue fluid, and once it enters the lymphatic vessels it is called lymph. Lymph vessels pass through lymph nodes, where the fluid is filtered and white blood cells are added, and finally empty back into the blood circulation.

The question gives you the decisive clue in its own stem — lymph is a tissue fluid in intercellular spaces. That immediately rules out anything inside a cell (cytoplasm), anything secreted into the gut (digestive juice) and anything on its way out of the body (urine). The one remaining option is the circulating fluid that lymph is derived from.

• Lymph is formed from plasma that filters out of the blood capillaries into the intercellular spaces.
• Lymph is similar to plasma in composition but contains much less protein, and it carries no red blood cells.
• Lymph vessels drain back into the blood circulation, so the fluid that leaks out of capillaries is returned.
• Lacteals, the lymph vessels in the villi of the small intestine, absorb digested fat into the lymph.

• Confusing lymph with cytoplasm because both are watery — one is outside cells, the other inside.
• Assuming lymph carries red blood cells; it carries white blood cells, chiefly lymphocytes.

A definition-style one-liner that tests whether you know lymph is derived from plasma rather than being a secretion or an excretion.

• practice — not a real PYQ

  Lymph differs from blood plasma mainly in having

  • (a)more protein
  • (b)less protein
  • (c)red blood cells
  • (d)no water

  Answer(b) less protein — the large plasma proteins mostly stay inside the capillary when tissue fluid is formed.

• practice — not a real PYQ

  Digested fat from the small intestine is absorbed mainly into the

  • (a)blood capillaries of the villi
  • (b)lacteals of the villi
  • (c)hepatic portal vein
  • (d)bile duct

  Answer(b) lacteals of the villi — lymph vessels that carry absorbed fat before it reaches the blood.