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In human beings, menstrual cycle ceases around at 50 years of age and there will be no production of egg. It is the phase in a woman's life when menopause occurs, ovulation and menstruation stop. Hence, a woman cannot conceive a child after 50 years of age.

Pregnancy occurs when the sperm and ovum reaches the ampullary isthmus junction of the fallopian tube at the same time. During every coitus both are not reaching at this position together.

GnRH acts on anterior pituitary and FSH acts on Sertoli cells of seminiferous tubules.

GnRH stimulates the release of two gonadotropin – Follicle stimulating hormone and leutenising hormone (LH) from the anterior pituitary. FSH stimulates the Sertoli cells to secrete some factors necessary for spermiogenesis.

Chorionic villi appear after implantation on the trophoblast. 

It becomes interdigitated with uterine tissue to form the placenta and increases the surface area for exchange of materials between the mother and the embryo.

 Stem cells....

Formation of mature female gamete, Ovary.

Oviduct (Fallopian tube/ampullary–isthmic junction).

Amniotic fluid.

(c) theca externa and theca intemna

Ciliated epithelial tissue.

It is a mature ovarian follicle in the ovary.

• In humans the mechanism is not completely understood; however, it is known that the initiation of spermatogenesis occurs at puberty due to the interaction of the hypothalamus, pituitary gland, and Leydig cells. If the pituitary gland is removed, spermatogenesis can still be initiated by follicle stimulating hormone (FSH) and testosterone.
•  FSH stimulates both the production of androgen-binding protein (ABP) by Sertoli cells and the formation of the blood-testis barrier. ABP is essential to concentrating testosterone in levels high enough to initiate and maintain spermatogenesis. 
• Intratesticular testosterone levels are 20–100 or 50–200 times higher than the concentration found in blood, although there is variation over a 5- to 10-fold range amongst healthy men.

Correct order = cleavage, blastomeres, morula, blastocyst, trophoblast, inner cell mass/ endometrium, implantation 

Cleavage: mitotic divisions starts as the zygote move through the oviduct towards the uterus and form (2/4/8/16) daughter cells called blastomeres. Embryo with 8 to 16 blastomeres is called a morula. Morula continues to divide and transforms into a blastocyst. Blastomeres in blastocyst are arranged into an outer layer called trophoblast and an inner group of cells attached to trophoblast called the inner cell mass. The trophoblast laver then gets attached to the endometrium and inner cell mass differentiates as the embryo. Ultimately blastocyst becomes embedded in the endometrium of uterus. This is called Implantation.

Progesterone –maintains endometrium- corpous luteum.

Progesterone hormone is essential for maintenance of endometrium of uterus, so that foetus may get implanted here.

LH surge is essential for the events leading to ovulation.

(i) The complete neuro-endocrine mechanism.

(ii) Oxytocin acts on uterine muscle for stronger contraction.

(iii) To ensure the fusion of one sperm.

(iv) Seminal plasma is a liquid medium which helps the sperm to move and nourishes it.

 Trophoblast.

Provide nutrition to germ cells.

Corpus luteum.

Fertilization refers to the fusion of a sperm and ovum in humans occurs in the ampullary isthmic junction of the fallopian tube.When a sperm comes in contact with the zona pellucida of the ovum, it induces changes in the membrane that. blocks the entry of other sperms. The secretions of acrosome help the sperm to digest the zona pellucida and plasma membrane of the ovum and enter into its cytoplasm.

The entry of sperm induces the completion of secondary meiotic division of the secondary oocyte resulting in the formation of a second polar body and a large ootid. The haploid nucleus of the ootid and that of the sperm fuse to form a diploid zygote.

 Ampullary-isthmic junction of fallopian tube.

During pregnancy, placenta produces hormones like human chorionic gonadotropin and human placental lactogen and ovary produces relaxin.

(a) Nipple 

(b) Ampulla 

(c) Fat

Human chorionic gonadotropin. Human placental lactogen. The source that secretes them is placenta.

Human chorionic gonadotropin (hCG)—Placenta. 

Human placental lactogen (hPL) — Placenta. 

Relaxin (towards the end of pregnancy)—Ovary.

(a) Hormone ‘X’: Luteinising hormone. 

Hormone ‘Y’: Follicle stimulating hormone. 

(b) 

(i) 5th day to 12th day of the cycle: Follicular phase (Proliferative phase). 

(ii) 14th day of the cycle: Ovulatory phase (release of ovum) followed by luteal phase. 

(iii) 16th day to 25th day of the cycle: Luteal phase. 

(iv) FSH is secreted by the anterior pituitary which stimulates the ovarian follicle to secrete estrogen, which in turn stimulates the proliferation of the endometrium of the uterine wall. 

(c) Both LH and FSH attain a peak level in the middle of cycle (about 14th day). Rapid secretion of LH leading to its maximum level during the mid-cycle called LH surge induces rupture of Graafian follicle and thereby the release of ovum (ovulation).

(a) Ovaries: During the first phase of menstrual cycle, growth of follicles occur and primary oocyte matures in the follicle. The mature Graafian follicle bursts to release the ovum. In luteal phase, the remaining follicle forms corpus luteum, an endocrine gland that produces progesterone. 

(b) Uterus: The inner walls of the uterus are highly vascularised and muscular in nature and is known as endometrium. This wall takes active part in menstrual cycle because it breaks down due to the lack of progesterone. As a result, bleeding occurs. In the follicular phase, uterus enlarges in size. 

(c) Fallopian tube: The wall of the fallopian tubes thickens and its cilia and their movements are increased.

(d) menarche

(i) Corpus luteum continues to secrete progesterone to maintain Pregnancy, it persists and produces progesterone.

(ii) It disintegrates and changes into corpus albicans.

(b) Helps in the collection of the ovum after ovulation.

1. 30 

2. 15

The basal part of endometrium remains intact during menstruation because it forms the source of new endometrial lining for the next such cycle.

(i) 46 

(ii) 23 

(iii) 46 

(iv) 46

(i) 46

(ii) 23

(iii) 46

(iv) 46

23 chromosomes are present in a human male sperm.

Chorionic villi appear after implantation on the trophoblast. It becomes interdigitated with uterine tissue to form the placenta and increases the surface area for exchange of materials between the mother and the embryo.

Correct option is b. Penis

(i) Signals for parturition originate from the fully developed foetus/placenta/foetal ejection reflex

(ii) Colostrum contains antibodies (IgA), to (passively) immunise the baby.

Menstrual cycle is regulated by hypothalamus through the pituitary gland. At the end of menstrual phase, the pituitary FSH gradually increases resulting in follicular development within the ovaries. As the follicles mature, estrogen secretion increases resulting in a surge in FSH and LH. The surge of LH is responsible for ovulation and formation of corpus luteum that secretes progesterone which helps in maintaining the endometrium for implantation.

The scrotum is a sac of skin that hangs outside the abdominal cavity. Since viable sperms cannot be produced at normal body temperature, the scrotum is placed outside the abdominal cavity to provide a temperature 2- 3°C lower than the normal internal body temperature. Thus, the scrotum acts as a thermoregulator for spermatogenesis.

Gonadotropins (LH and FSH) are secreted by the anterior lobe of pituitary gland. 

Gonadotropins (LH and FSH) increase gradually during the follicular phase (proliferative phase) of menstrual cycle and stimulate follicular development as well as secretion of estrogen by the growing follicles. 

LH and FSH attain a peak level in the middle of the cycle (about 14th day) and rapid secretion of LH induces rupture of Graafian follicle followed by ovulation (release of ovum). 

LH stimulates transformation of Graafian follicle into corpus luteum.

(a) The milk secreted has nutrients and contain antibodies Ig A, Immunoglobuling or Ig A provide passives immunity.

(b) Colostrum

(i) Location: Lines inside the seminiferous tubules. 

Functions: Provide nutrition to the germ cells sperms.

(ii) Location: Outside seminiferous tubules in interstitial. 

Functions: Synthesise or secrete male hormones or androgens.

It is a passage connecting scrotum with pelvic cavity.

(i) Menstruation is a normal physiological process in the body of all normal women at puberty. This helps in reproduction. Therefore, the question of not allowing the women during this period of menstruation is not justified. 

(ii) Following values are not exhibited by such women : 

(a) Self-awareness about the body 

(b) Empathy.

Menopause is the phase in a women’s life when ovulation and menstruation stops. The average age of menopause is 45-50 years. It indicates the permanent cessation of the primary functions of the ovaries.

The sperms deposited in the female reproductive tract undergo capacitation. It is a bio chemical event that makes the sperm to penetrate and fertilize the egg.

If the fertilized ovum is implanted outside the uterus it results in ectopic pregnancy. About 95 percent of ectopic pregnancies occur in the fallopian tube. The growth of the embryo may cause internal bleeding, infection and in some cases even death due to rupture of the fallopian tube.