What effect does luteinizing hormone (LH) have on a female?

Correct Answer: D

Rationale: The correct answer is D: LH triggers ovulation in a female. LH is a hormone released by the pituitary gland that stimulates the release of an egg from the ovary during the menstrual cycle. This process is known as ovulation. It is a crucial step in the reproductive cycle of females. A: LH does not promote the enlargement of female breasts. Breast growth is primarily regulated by estrogen and progesterone. B: LH does have a significant effect on females, particularly in the reproductive system. C: While LH does contribute to the development of secondary sex characteristics in females, its main role is in triggering ovulation.

Correct Answer: D

Rationale: Step-by-step rationale for why the correct answer is D: 1. Testes are the male gonads responsible for producing sperm. 2. The testes function as the primary reproductive organ in males. 3. Sperm production occurs in the seminiferous tubules within the testes. 4. The testes also produce testosterone, the primary male sex hormone. Summary of why other choices are incorrect: A: Producing - While testes do produce sperm, this choice lacks specificity regarding the male gonads. B: Estrogen functions and are called ________ - Estrogen is a female sex hormone, not produced by male gonads. C: Progesterone - Progesterone is a female sex hormone produced mainly by the ovaries, not by male gonads.

Correct Answer: D

Rationale: The correct answer is D: 14 days. During oogenesis, the process of ovulation occurs approximately 14 days prior to the start of the next menstrual cycle. This is crucial for timing fertilization and pregnancy. The other choices are incorrect because: A: an ovum is the mature egg released during ovulation, not directly related to the menstrual cycle. B: 7 days is not a relevant timeframe in the context of oogenesis and menstrual cycles. C: a primary oocyte is the initial stage of egg development and needs further maturation before ovulation, not directly linked to the menstrual cycle timing.

Correct Answer: D

Rationale: The correct answer is D: Sertoli cells. Seminiferous tubules are lined with Sertoli cells, which provide structural support and nourishment to developing sperm cells. These cells also help in the process of spermatogenesis. A: Oocytes are female germ cells found in the ovaries, not in the seminiferous tubules. B: Red blood cells are not found in the seminiferous tubules. They are responsible for carrying oxygen in the bloodstream. C: Leydig cells are found in the interstitial tissue of the testes and are responsible for producing testosterone, not lining the seminiferous tubules. Therefore, the correct choice is D as Sertoli cells play a crucial role in sperm production within the seminiferous tubules.

Correct Answer: A

Rationale: The correct answer is A because oestrogen actually has a negative feedback effect on the hypothalamus. When oestrogen levels rise, it signals the hypothalamus to stop producing gonadotropin-releasing hormone (GnRH), which in turn decreases follicle-stimulating hormone (FSH) and luteinizing hormone (LH) production. This negative feedback loop helps regulate the menstrual cycle. Choices B, C, and D are correct statements about oestrogen. Oestrogen does stimulate retention of fluid, growth of ovaries and follicles, and the development of female body characteristics.