Human Reproduction

Human Reproduction

Human reproduction encompasses the whole process from fertilization to childbirth. Humans are sexually reproducing, internally fertilizing, and viviparous organisms. The reproductive system of humans includes the primary sex organs that produce the gametes, and secondary organs that show secondary sexual characteristics that separate males from females and help in the whole process of reproduction. We humans are sexually dimorphic i.e. there is a remarkable difference between male and female reproductive events, and these events only occur when a person achieves puberty. The events include the following stages;...

Human Reproductive System

The human Reproductive system is divided into two types i.e., Male and Female Reproductive Systems:...

Male Reproductive System

The male reproductive system is mostly located externally in the pelvic region of the body. It consists of the testes (primary sex organ), accessory ducts, accessory glands, and external genitalia....

Female Reproductive System

Female Reproductive System is located internally in the pelvic region of the lower abdomen. It consists of a pair of ovaries (primary sex organ), a pair of oviducts, a uterus, a cervix, a vagina, and external genitalia. Along with these structures, there is a pair of mammary glands that acts in a pattern to maintain the process of ovulation, fertilization, pregnancy, parturition, and lactation....

Gametogenesis

The process of formation of gametes (sperm and ovum) by meiosis in the primary sex organs i.e. testis in males and ovaries in females is called gametogenesis. The formation of sperm by the testis is called spermatogenesis and the formation of the ovum by ovaries is called oogenesis....

Menstrual Cycle

It is the reproductive cycle in female primates e.g. monkeys, apes, and human beings. The first menstruation begins at puberty and is called menarche. Menstrual cycles cease around 50 years of age; that is termed menopause. In human females, menstruation is repeated at an average interval of about 28/29 days, and the cycle of events starting from one menstruation to the next one is called the menstrual cycle. It has four phases;...

Fertilization and Implantation

During copulation (coitus) insemination takes place i.e. semen containing sperm cells is released by the penis into the vagina. The motile sperms swim rapidly, pass through the cervix, enter into the uterus, and finally reach the junction of the isthmus and ampulla (ampullary-isthmic junction) of the fallopian tube. On the other hand, the ovum released by the ovary is also transported to the ampullary-isthmic junction where fertilization takes place. For the process of fertilization to take place the sperm cells first have to undergo capacitation in which the sperm cells get activated by the secretion of the female genital tract for the release of enzymes stored in the acrosome....

Pregnancy and Embryonic Development

Immediately after implantation, the inner cell mass (embryo) differentiates into an outer layer called ectoderm and an inner layer called endoderm, and in between a mesoderm soon appears. These three layers give rise to all tissues (organs) in adults....

Parturition and Lactation

Vigorous contraction of the uterus at the end of pregnancy causes expulsion/delivery of the fetus is called parturition. It is controlled by a neuroendocrine mechanism that includes the following steps;...

FAQs on Human Reproduction

Q1: If there are 15 primary spermatocytes, how many sperm cells will be produced?...