Fertilisation, Implantation, Pregnancy and Parturition
Zygote to blastocyst, placenta, gestation hormones, birth and lactation. (Biology › Human Reproduction, NEET UG syllabus.)
What is Fertilisation, Implantation, Pregnancy and Parturition?
The process of fusion of male and female gametes (sperm and ovum) to form a diploid zygote.
Key points
- Describe the process and site of fertilisation.
- Explain the events of cleavage and blastocyst formation.
- Detail the process of implantation.
- Describe the structure and functions of the placenta.
Common exam trap
Confusing the site of fertilisation (fallopian tube) with the site of implantation (uterus).
Definitions
- Term
Fertilisation
- Meaning
The process of fusion of male and female gametes (sperm and ovum) to form a diploid zygote.
- Term
Implantation
- Meaning
The embedding of the blastocyst into the endometrium of the uterus.
- Term
Placenta
- Meaning
A temporary organ that connects the developing foetus to the uterine wall, providing nutrients, oxygen, and removing waste products, and acting as an endocrine gland.
- Term
Gestation
- Meaning
The period of development of the embryo or foetus inside the mother's womb, from conception to birth.
- Term
Parturition
- Meaning
The process of childbirth, involving uterine contractions to expel the foetus and placenta.
- Term
Lactation
- Meaning
The process of milk production and secretion by the mammary glands after childbirth.
Learning objectives
Describe the process and site of fertilisation.
Explain the events of cleavage and blastocyst formation.
Detail the process of implantation.
Describe the structure and functions of the placenta.
List and explain the roles of hormones during pregnancy.
Outline the major events of embryonic and foetal development.
Explain the neuroendocrine mechanism of parturition.
Describe the process of lactation and its hormonal control.
Prerequisites
Basic knowledge of male and female reproductive systems.
Understanding of gametogenesis (spermatogenesis and oogenesis).
Familiarity with hormonal regulation in the menstrual cycle.
Common mistakes
Confusing the site of fertilisation (fallopian tube) with the site of implantation (uterus).
Mixing up the functions of oxytocin (contractions, milk ejection) and prolactin (milk production).
Incorrectly identifying the origin of hormones like hCG (placenta, not pituitary).
Misunderstanding the sequence of cleavage stages (zygote → morula → blastocyst).
Forgetting that the placenta also acts as an endocrine gland.
Keywords
Fertilisation
Zygote
Cleavage
Morula
Blastocyst
Implantation
Placenta
hCG
hPL
Estrogen
Progesterone
Gestation
Parturition
Oxytocin
Relaxin
Lactation
Prolactin
Embryo
Foetus
Zona Pellucida
Cortical Reaction
Practice preview
A woman's urine sample tests positive for hCG. Which of the following events has most likely occurred and is being indicated by this hormone?…
hard
Which of the following is NOT a primary function of the placenta?…
easy
Which hormone is primarily responsible for maintaining the endometrium during pregnancy after implantation, initially secreted by the corpus luteum and later by the placenta?…
medium