Spermatogenesis
Read the following passage carefully and answer the given questions.
As you are aware, humans are sexually reproducing and viviparous. The reproductive events in humans include formation of gametes (gametogenesis), i.e., sperms in males and ovum in females. Male reproductive system is composed of a pair of testes, the male sex accessory ducts, accessory glands, and external genitalia. Each testicular lobule contains one to three highly coiled seminiferous tubules in which sperms are produced. Each seminiferous tubule is lined on its inside by two types of cells called male germ cells (spermatogonia) and Sertoli cells. The male germ cells undergo meiotic divisions finally leading to sperm formation, while Sertoli cells provide nutrition to the germ cells. The regions outside the seminiferous tubules called interstitial spaces, contain small blood vessels and interstitial cells or Leydig cells. The male sex accessory ducts include rete testis, vasa efferentia, epididymis and vas deferens. The male accessory glands include paired seminal vesicles, a prostate and paired bulbourethral glands. Secretions of these glands constitute the seminal plasma which is rich in fructose, calcium and certain enzymes.
LH acts on _________ cells and FSH acts on _________ cells, respectively.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Leydig, Sertoli
The testis has two kinds of non-germ cells. Leydig cells lie outside the seminiferous tubules, in the interstitial spaces. Sertoli cells lie inside the tubules and feed the germ cells.
(1) Leydig, Sertoli — Correct. LH acts on the Leydig cells, which make and release androgens. The androgens stimulate spermatogenesis. FSH acts on the Sertoli cells, which release factors that help the change of spermatids into sperms (spermiogenesis).
(2) Sertoli, Leydig — Incorrect. The two target cells are placed the wrong way round.
(3) Spermatids, Sertoli — Incorrect. Spermatids are germ cells. LH does not act on them but on the Leydig cells.
(4) Primary spermatocyte, secondary spermatocyte — Incorrect. Both are germ cells. Neither LH nor FSH acts on them directly. They act on the Leydig and Sertoli cells.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.
NCERT Extract:
Gametogenesis – “… LH acts at the Leydig cells and stimulates synthesis and secretion of androgens. Androgens, in turn, stimulate the process of spermatogenesis. FSH acts on the Sertoli cells and stimulates secretion of some factors which help in the process of spermiogenesis.”