Chapter 27, Problem 1CYR

Match the correct time period of gestation with the prenatal period of development:

_____________ Pre-embryonic period

______________Fetal period

______________Embryonic period

a. Weeks 3–8

b. Weeks 1–2

c. Weeks 9–38

Summary Introduction

To review:

Match the correct period of gestation with the prenatal period of development:

______ Pre-embryonic period

______ Fetal period

______ Embryonic period

a. Weeks 3-8

b. Weeks 1-2

c. Weeks 9-38

Introduction:

Pregnancy includesall the processes that lead to conception, where an oocyte is developed, until the birth of thechild. The oocyte is developed during the gestation period, which lasts from the menstrual period until the birth of a child, which is for a time period of 40 weeks. This gestation period is longer than theprenatal period.

Explanation of Solution

The pre-embryonic period lasts for the first two weeks after fertilization, when the secondary oocyte is fertilized by the aid of the sperm cell and the secondary oocyte undergoes the process of meiosis II in order to turn into an ovum. The female and the male nuclei come together to give rise to a zygote. Hence, weeks 1-2 is the correct time period for the pre-embryonic period.

During the fetal period, the gestation process occurs from week 9 to week 38, till birth. In this, the conceptus is known as thefetus, which grows larger to develop the organ systems that function without the aid from the mother later. Thus, weeks 9-38 consist of the fetal period.

The embryonic period lasts the third week to the eighthweek of gestation. Thus, weeks 3-8 consist of the embryonic period. During this phase, the conceptus grows rapidly, and forms and folds into the rudimentary organ systems.

Conclusion

Term	Period
Pre-embryonic period	(b)Weeks 1-2
Embryonic period	(a)Weeks 3-8
Fetal period	(c)Weeks 9-38