Human Reproduction Test - 19

At the end of meiosis I females have two daughter cells and meiosis II only occurs if and when the fertilization occurs by the sperm cell.

Meiosis II starts after the sperm proceeds fertilization process in female.

Parturition is an induced Complex neuroendocrine mechanism. In this signals are originated from a fully developed foetus and placenta. This lead to mild uterine contractions and hence fetal ejection reflex.
Then Oxytocin is released from maternal pituitary and it acts on uterine muscles leading to strong uterine contractions.

This further continues to stronger and stronger contractions. As a result, the baby is expelled out of the uterus with placenta through the birth canal.

Hysterectomy is the surgical removal of uterus. It may also involve removal of the cervix, ovaries. Fallopian tubes and other surrounding structures.

The first phase of human menstrual cycle is called proliferative phase (follicular phase), while second phase of human menstrual cycle is called as secretory phase or luteal phase and it lasts for about 13 days.

Here, the LH is secreted by anterior lobe of pituitary leading to ovulation.

Male accessory glands in humans are the seminal vesicles, prostate gland, and the bulbourethral glands. Secretion of accessory sex glands is called seminal plasma. It is rich in fructose (source of energy), citrate, prostaglandins, calcium and certain enzymes.

Seminal fluid along with the sperms is called semen or seminal fluid. It also maintains the viability and motility of sperms as it provides proper pH (approximately pH 7.5) and ionic strength.

The act of expelling the full term young one from the mother's uterus at the end of gestation period is called parturition. Parturition is induced by signals from both the fully developed foetus and the placenta. It induces mild uterine contractions called foetal ejection reflex.

The amnion is a bilayered membranous sac which surrounds and prevents desiccation of embryo inside the uterus, enclosing the amniotic cavity (amnion).

Sertoli cells are the cells that line the seminiferous tubules in the testis. It helps in spermatogenesis. It also nourishes the cells of the testis so they are also known as nurse cells. It is activated by the FSH hormone which is secreted by the anterior pituitary.

It also phagocytoses the residual cytoplasm.

Cleavage indicates the divisions of cells early embryo which is called the ad blastula stage. Blastomeres after cleavage will be small in size due to the short span of the Interphase stage of mitosis, hence resulting in the small size of cells.

Cleavage is a series of rapid mitotic divisions of the zygote which convert the single celled zygote into a multicellular structure called blastula (blastocyst). About thirty hours after fertilization, the newly formed zygote divides into two cells, the Blastomeres, in the upper portion of the Fallopian tube.

This is the first cleavage. The next division occurs within forty hours after fertilization. The third division occurs about three days after fertilization.

During these early cleavages, the young embryo is slowly moving down the fallopian tube towards the uterus. At the end of fourth day, the embryo reaches the uterus. It has thirty two cells.