Conception and Prenatal Development

Flashcards covering key concepts and terms related to conception and prenatal development.

What is gametogenesis?

The creation of reproductive cells that requires meiosis, resulting in gametes with half the number of chromosomes.

What occurs during oogenesis?

Formation of ova begins during prenatal life, and all ova a female will ever have are developed by the 30th week of gestation.

What is spermatogenesis?

Formation of sperm, beginning during fetal life and continuing throughout a man's life after puberty.

What is required for conception?

Correct timing between ovulation and ejaculation of healthy sperm; the ovum must be fertilized within 24 hours after ovulation.

What are the major events during the pre-embryonic period?

Initiation of cell division, formation of morula and blastocyst, entry of zygote into the uterus, and implantation.

What happens during the embryonic period?

Extends from the 3rd week to the 8th week after conception, where all major organ systems are established.

What are the derivatives of the ectoderm?

Includes the brain and spinal cord, hair, nails, sensory epithelium, and peripheral nervous system.

What does the mesoderm develop into?

Cartilage, bone, muscle tissue, kidneys, heart, and blood vessels.

Which structures are formed from the endoderm?

Tonsils, liver, pancreas, lining of gastrointestinal and respiratory tracts.

What happens during the fetal period?

Begins 9 weeks after conception, where the cells become a fetus with dramatic growth and refinement of organ systems.

What is the function of the placenta?

Metabolic functions, substance transfer between mother and fetus, and has endocrine functions.

What circulatory shunts bypass the fetal liver and lungs?

Ductus venosus, foramen ovale, and ductus arteriosus.

What is multifetal pregnancy?

A pregnancy involving more than one fetus, commonly seen with twins which may be monozygotic or dizygotic.

What are dizygotic twins?

Twins that develop from two separate eggs fertilized by two separate sperm.

What factors can increase the likelihood of having dizygotic twins?

Certain families, specific racial groups, older mothers, and women undergoing infertility therapy.