This category covers the biological processes underlying human reproduction, including gamete development, hormonal regulation, fertilization, and early embryonic development.
Estrogen is the key hormone responsible for the development of secondary sexual characteristics in females.
Ref: NCERT Class 12 Biology Chapter 2: Human Reproduction Menstrual Cycle Fertilization Implantation Pregnancy Parturition Lactation
Oxytocin is released from the posterior pituitary and triggers the contraction of myoepithelial cells, leading to milk ejection.
Ref: NCERT Class 12 Biology Chapter 2: Human Reproduction Menstrual Cycle Fertilization Implantation Pregnancy Parturition Lactation
FSH stimulates the growth and maturation of ovarian follicles during the early (follicular) phase of the menstrual cycle.
Ref: NCERT Class 12 Biology Chapter 2: Human Reproduction Menstrual Cycle Fertilization Implantation Pregnancy Parturition Lactation
Progesterone maintains uterine quiescence (prevents contractions) throughout pregnancy until labor begins.
Ref: NCERT Class 12 Biology Chapter 2: Human Reproduction Menstrual Cycle Fertilization Implantation Pregnancy Parturition Lactation
The LH surge in the mid-cycle triggers the release of the oocyte from the follicle.
Ref: NCERT Class 12 Biology Chapter 2: Human Reproduction Menstrual Cycle Fertilization Implantation Pregnancy Parturition Lactation
The withdrawal of estrogen and progesterone levels, when fertilization does not occur, leads to the shedding of the endometrium (menstruation).
Ref: NCERT Class 12 Biology Chapter 2: Human Reproduction Menstrual Cycle Fertilization Implantation Pregnancy Parturition Lactation
The acrosomal reaction releases enzymes that digest the zona pellucida, enabling the sperm to penetrate and fuse with the oocyte.
Ref: NCERT Class 12 Biology Chapter 2: Human Reproduction Menstrual Cycle Fertilization Implantation Pregnancy Parturition Lactation
Humans exhibit discoid placentation, where the placenta forms a disc-shaped structure on the uterine wall.
Ref: NCERT Class 12 Biology Chapter 2: Human Reproduction Menstrual Cycle Fertilization Implantation Pregnancy Parturition Lactation
Following fertilization, the zygote undergoes cleavage, forming a morula before further development into a blastocyst.
Ref: NCERT Class 12 Biology Chapter 2: Human Reproduction Menstrual Cycle Fertilization Implantation Pregnancy Parturition Lactation
Embryo transfer (ET) is the final step in IVF where the cultured embryo is placed into the uterine cavity for implantation.
Ref: NCERT Class 12 Biology Chapter 2: Human Reproduction Menstrual Cycle Fertilization Implantation Pregnancy Parturition Lactation
hCG is secreted by the trophoblast soon after implantation and is the hormone detected by pregnancy tests.
Ref: NCERT Class 12 Biology Chapter 2: Human Reproduction Menstrual Cycle Fertilization Implantation Pregnancy Parturition Lactation
During the luteal phase, under the influence of progesterone, the endometrium becomes thick and receptive to the implantation of a fertilized egg.
Ref: NCERT Class 12 Biology Chapter 2: Human Reproduction Menstrual Cycle Fertilization Implantation Pregnancy Parturition Lactation
