• Trophoblast - helps in implantation / attachment to endometrium / attachment to uterus.
• Inner cell mass - gets differentiated into an embryo.

Colostrum, rich in nutrients, rich in antibodies/ rich in IgA/provide passive immunity/provides immunity to new born/helps to develop resistance in new born/readily available for new born/ hygenic/develops a bond between mother and child.

Spermatogonia undergo the process of spermatogenesis while Sertoli cells helps spermiation.
The process of formation of spermatids is called spermatogenesis. It occurs in spermatogonia of seminiferous tubules. The process of release of mature sperms is called spermiation.

(a) I  - Teritiary follicle
II  - Ampullary-isthmic junction
III  - Ampullary-isthmic junction
IV  - Endometrium of uterus.
(b) The signals originate from the fully developed foetus and the placenta.
Pituitary releases oxytocin,that stimulates stronger contractions of the uterine muscles.

(a) The primary oocyte grows in size and completes meosis I,forming a larger haploid cell,the secondary oocyte and a smaller cell,the first polar body.
(b) In the luteal phase,the ruptured graafian follicle transforms into corpus luteum.
Corpus luteum secretes large quantity of progesterone to maintain the endometrium.

Each fallopian tube extends from the periphery of each ovary to the uterus.
The part of the fallopian tube closer to the ovary is the funnel-shaped infundibulum.
The edges of the infundibulum possess finger like projections,called fimbriae.
The infundibulum leads to the wider part of the fallopian tube,called ampulla.
The last part of the oviduct with a narrow lumen;is called isthmus;it joins the uterus.

Duct System of male Reproductive System.
The intratesticular duct system starts with tubuli recti,which are the short,straight end segments of the seminiferous tubules ;these tubules connect the seminiferous tubules to the cuboidal epithelium-lined channels,called rete testis.
Form the rete testis arise 10-20 fine tubules,called vasa efferentia that leave the testis and open into the epididymis.
Epididymis is a single convoluted tubule that is located along the posterior surface of the testis.
The epididymis continues as the vas-deferens,that ascends into the abdominal cavity through inguinal canal.
It loops over the urinary bladder and receives a duct from the seminal vesicle of its side to form ejaculatory duct that runs through the prostate and opens into the prostatic urethra,just after its emergence from the urinary bladder.
The urethra receives the ducts of prostate gland and bulbourethral glands,a little ahead and runs through the penis to its openning called urethral meatus,to the outside.

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The male accessory ducts are rete testis, vasa efferentia, epididymis and vas deferens.These ducts store and transport the sperms from the testes to the outside through the urethra. The male accessory glands are paired seminal vesicles, prostate gland and paired Bulbourethral glands. The secretion of these glands forms seminal plasma, which is rich in fructose, calcium and certain enzymes. The secretion of Bulbourethral glands lubricates the glans penis.

Luteinizing hormone influences Leydig cells;they secrete the hormone,testosterone.

Follicle stimulating hormone influences Sertoli cells;they produce certain factors necessary for spermiogenesis.

Gondotropins are secreted by the anterior pituitary.

Follicle stimulating hormone (FSH) and luteinising hormone (LH) are the gonadotropins.

FSH stimulates follicular development and secretion of estrogens by the follicle cells.

Both FSH and LH attain a peak level around the middle of the cycle(about 14th day).

The maximum level of LH (also called LH surge) induces ovulation,i.e.,rupture of the mature follicle and release of ovum/secondary oocyte.

LH stimulates the formation of corpus luteum from the ruptured follicle and secretion of progesterone from the corpus luteum.

a) Structure of ovum. Most animal eggs are spherical or oval, non-motile but on close examination. it is noted that one pole is different from the other. The pole from which polar bodies are given off is called animal pole while the opposite is termed as vegetal pole. Thus it is said to have polarity. Thus various cytoplasmic substances are distributed along the axis in unequal manner. The nucleus also called (germinal vesicle) having chromatin network is surrounded by nuclear membrane. It also contains prominent nucleolus. All animal eggs contain some reserve material to provide food called yolk. The cytoplasm of ovum is called ooplasm. It lacks centrosome but contains cortical granules derived from Golgi bodies in its outer region termed cortex.
(b) Function of Zona pellucida. During fertilisation as a result of cortical reaction, zona pellucida hardens and prevents the entry of additional sperms (polyspermy).