Human Reproduction Test - 46

During menstruation cycle, maturation of the follicle is stimulated by follicle stimulating hormone (FSH) from the anterior pituitary, and estrogen is secreted by the follicle lining cells. Ovulation is triggered by a surge of luteinizing hormone (LH) from the anterior pituitary, which occurs a few hours before ovulation. After ovulation, the follicle lining cells develop into the corpus luteum (yellow body), under the influence of LH from the anterior pituitary. The corpus luteum produces the hormone progesterone and some oestrogen. If the ovum is fertilised it embeds itself in the wall of the uterus, where it grows and develops and produces the hormone human chorionic gonadotrophin (hCG), which stimulates the corpus luteum to continue secreting progesterone and oestrogen for the first 3 months of the pregnancy, after which time this function is continued by the placenta. If the ovum is not fertilized the corpus luteum degenerates and a new cycle begins with menstruation.

Sustentacular cells are supporting cells of the seminiferous tubules of the testis; responsible for the differentiation of spermatids, the maintenance of the blood-testis barrier, and the secretion of inhibin, androgen-binding protein, and Mullerian-inhibiting factor. They are not concerned with endocrine functions of testes.

Ovulation is the process in which egg is released from the mature Graafian follicle. This stage of the menstrual cycle is also called ovulatory phase in which the ovary is released on the 16th day of the menstrual cycle if the duration of a menstrual cycle is of 30 days. This phase takes place due to an increase in the luteinizing hormone called as LH surge. Thus the correct answer is option D,

Menopause is the cessation of the monthly cycle wherein ovaries do not respond to gonadotropic hormones produced by the anterior pituitary and do not secrete oestrogens and progesterone. It marks the end of a reproductive phase of the human female. Deposition of subcutaneous fat, the presence of pubic hair and development of mammary glands are secondary sexual characters in human females. The correct answer is A.

Male accessory glands in humans are the seminal vesicles, prostate gland and the Cowper's glands. The products of these glands serve following functions: 
1. Nourish and activate the spermatozoa
2. Clear the urethral tract prior to ejaculation
3. Serve as the vehicle of transport of the spermatozoa in the female tract. Hence, option D is correct.

Solution

Correct answer is option A.

Explanation for correct option:

• Hormonal control of spermatogenesis is as follows:
• Hypothalamus secrets Gonadotropin releasing hormone (GnRH), which in turn stimulates the anterior pituitary gland to secret 2 hormones i.e., FSH and LH.
• FSH acts on Sertoli cells while LH acts of Leydig cells.
• Sertoli cells nourishes the spermatocytes and has role in spermatogenesis. While Leydig cells produces androgens such as testosterone. 

The menstrual cycle is divided into four phases, namely menstrual phase (day 1 to 5), proliferative phase (day 1 to 13), ovulation phase (day 14) and luteal phase (day 15 to 28). During menstrual phase, the uterus sheds its inner lining that exits the body in the form of menstrual fluid. During proliferative phase, eggs grow in the ovaries and single egg matures into a follicle. Simultaneously endometrium develops in the uterus. Proliferative phase ends when ovulation occurs. During ovulation phase, egg is released from the ovary. During luteal phase, the egg released remains in the Fallopian tube for 24 hours. If fertilization does not occur, egg disintegrate and menstrual phase of next cycle begins. 

The follicular phase is the first part of the ovarian cycle. During this phase, the ovarian follicles mature and get ready to release an egg. It usually lasts 7-8 days. Hence, option A is correct.

When a woman is born there are usually one million eggs in each ovary and one egg will be released, when she ovulates every month during her menstrual cycle, which is approximately 400-500 eggs over her lifetime. As a woman gets older the rest of the eggs disappear, break down or deteriorate and by the time she reaches menopause, there are no eggs left. Thus, the correct answer is option B.