Question

During early pregnancy progesterone is secreted by
(a) Corpus luteum
(b) FSH
(c) Thyroid
(d) None of the above

Answer 1

Hint: The ovum is shed from the ovary by the rupture of the follicle. The shedding of the ovum from a Graafian follicle is called ovulation. The remaining parts of follicle form a structure which releases progesterone during early pregnancy.

Complete answer:
Corpus Luteum is a yellow-coloured body structure which is the remains of the Graafian Follicle after the release of the developing ovum. The cytoplasm of the corpus luteum is filled with a yellow pigment called lutein. The corpus luteum grows for a few days and if the ovum is fertilized and the pregnancy results, it continues to grow. It releases large amounts of progesterone. It is needed for the maintenance of endometrium, which is required for the implantation of the fertilised ovum and other events of pregnancy. After the fertilisation and implantation of the embryo in the endometrium of the uterus, the corpus luteum continues to secrete progesterone for 7-9 weeks. This hormone is essential for the continuity of blood supply and oxygen supply to the foetus. It also supports the uterine linings to become thick enough to surround the embryo.

Additional Information: -The thyroid gland is made up of two lobes which are situated on either side of the trachea. The follicle cells in thyroid gland synthesise two hormones namely tetraiodothyronine or thyroxine and triiodothyronine. These hormones play a very crucial role in the regulation of basal metabolic rate (BMR). Thyroid hormones are also responsible for the maintenance of water and electrolyte balance.
-FSH is a follicle-stimulating hormone secreted by the anterior pituitary. This hormone further targets the ovarian follicles and stimulates their growth and also the secretion of oestrogen in females. In males, it stimulates spermatogenesis in testes.
So, the correct answer is ‘Corpus luteum.’

Note: -The ovary is the primary sex organ in females. Its surface is covered by germinal epithelium which lines the ovarian stroma.
-This ovarian stroma is divided into two regions namely a peripheral cortex and an inner medulla. The cortex contains numerous sac-like structures known as ovarian follicles. The medulla is filled with loose connective tissue, elastic fibres, numerous blood vessels, and smooth muscle fibres.