When does the fetus develop a functional nervous system?
1 Answer
It is a long process, even begins at conception.
Explanation:
The fetal nervous system -- i.e., your baby-to-be's brain and spinal cord -- is one of the very first systems to develop. In fact, it's making big strides before you even know you're pregnant.
First Trimester:
At week 6 or 7, the neural tube then bulges into 3 sections--forebrain, midbrain, and hindbrain (where it will soon develop into your baby's spinal cord). Soon these areas then morph into five different regions: cerebrum, cerebellum, brain stem, pituitary gland, and the hypothalamus.
While at the same time, special neural cells form throughout the embryo to form the very beginnings of nerves. As each of these neural cells form and connect to each other, they result in early fetal movements, like the baby's curling into the fetal position.
Around week 8, the fetus should begin his development of the limbs, and the sense of touch.
In the second trimester, the baby begins to suck, swallow, blinks, and even dreams! This is around 16 weeks to 21 weeks. This means that the sense of taste begins to develop as well. Myelin starts to grow and covers the nerves. This may even take until the baby's birth. By now, the fetal nervous system is developed enough for the baby to hear noises outside the womb!
By 28 weeks, fetal brainwave activity features sleep cycles that feature dreaming!
At the third trimester, the baby's brain grows with the rapid development of neurons until birth.
Hope this helps. :-)
This is only an overview.
You may read more here: http://www.wisegeek.org/what-are-the-stages-of-fetal-development.htm http://www.whattoexpect.com/pregnancy/fetal-brain-nervous-system/
