Tag: parts of the brain

Trophoblast refers to outer cells of a blastocyst that serve in placenta formation in the beginning of the second trimester. It secretes human chorionic gonadotropin that ensures persistence of the corpus luteum. The later serves to secrete ovarian hormone estrogen, progesterone, and relaxin that are required to maintain pregnancy. Hence, removal of ovaries after 4th month would not affect the pregnancy. The correct answer is C.

FSH is primarily involved in stimulating the growth of ovarian follicles, while LH induces ovulation. At ovulation, the ovum or egg is released and the ruptured follicle is transformed into a corpus luteum, which secretes progesterone as its main product. 

Leydig cells, also known as interstitial cells of Leydig, are found adjacent to the seminiferous tubules in the testicle. They produce testosterone in the presence of luteinizing hormone (LH). 

Gonadotropin-releasing hormone (GnRH) is secreted by the hypothalamus and stimulates the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary gland. 

The corpus luteum in the ovaries is the major site of progesterone production in humans, progesterone is also produced in smaller quantities by the ovaries themselves, the adrenal glands and, during pregnancy, the placenta.

Progesterone belongs to a group of steroid hormones called as progestogens. It is mainly secreted by the corpus luteum in the ovary during the second half of the menstrual cycle. It plays important roles in the menstrual cycle and in maintaining the early stages of pregnancy. The progesterone prepares the body for pregnancy in the event, that the released egg is fertilised. If the egg is not fertilised, the corpus luteum breaks down, the production of progesterone falls and a new menstrual cycle begins. Hence, progesterone is called as the 'anti abortion' hormone. 

When contraction of the uterus starts, oxytocin is released, which stimulates more contractions and more oxytocin is released. In this way, contractions increase in intensity and frequency. Oxytocin causes contractions during the second and third stages of labor.

Pheromones are chemicals released by an organism into its environment enabling it to communicate with other members of its own species. It changes the behaviour of another animal of the same species (animals include insects). 

Formic acid is the simplest carboxylic acid and occurs naturally, mostly in ant venom. 

The corpus luteum is a temporary endocrine structure in female mammals, that is involved in the production of progesterone and moderate levels of estradiol and inhibin. The corpus luteum develops from an ovarian follicle during the luteal phase of the menstrual cycle or oestrous cycle, following the release of a secondary oocyte from the follicle during ovulation.