Prenatal Growth and Functional Development

Question 1

What are the stages of prenatal growth?

Answer 1

Period of the egg
Period of the embryo
Period of the fetus

Question 2

What are the characteristics of the period of the egg?

Answer 2

First two weeks after fertilization
Rapid cell division in sequence:
1) Morula
2) Blastocyst
3) Implantation
4) Differentiation of cellular layers

Question 3

What are the characteristics of the period of the embryo?

Answer 3

Weeks 3-8
Rapid growth continues
Differentiation of stem cells into specific cell types:
- totipotent
- Pluripotent
-Multipotent
Organization of cell types into tissues==> organs
By end of period all basic anatomic and physiologic features established

Question 4

What are the characteristics of the period of the fetus?

Answer 4

Weeks 9-40 (gestation can vary from 38-42 weeks)
Rapid growth
Changes in proportions
Functional development of: tissues, organs, systems

Question 5

What are the prenatal growth characteristics?

Answer 5

Weight gain over time= sigmoid curve (s-curve)
10-12% of birth weight at week 20 (half-term) vs 50% length at week 20

Fetal period features major changes in proportions of body segments: head, trunk and lower extremities

Question 6

What are the characteristics of fetal motor activity?

Answer 6

Baby starts to move at 12 weeks, mom feels it at 20 weeks

Gestational age specific: neuromuscular changes, primary reflexes, muscle tone, reactivity, motility, sensorimotor behaviour
Spontaneous motor activity is part of normal development of muscles and joints
Fetal motor behaviours are precursors to postnatal motor behaviours