| |
Capítulo 40 3 a 4 Meses (12 a 16 Semanas): Papilas Gustativas, Movimento de Mandíbula, Reflexo de Sucção, Percepção dos Primeiros Movimentos do Feto
|
| |
| Between 11 and 12 weeks,
fetal weight increases
nearly 60%.
Twelve weeks marks the end
of the first third,
or trimester, of pregnancy.
|
| Distinct taste buds now cover
the inside of the mouth.
|
| By birth, taste buds
will remain
only on the tongue
and roof of the mouth.
|
| Bowel movements begin
as early as 12 weeks
and continue for about 6 weeks.
The material first expelled from
the fetal and newborn colon
is called meconium.
It is composed
of digestive enzymes,
proteins, and dead cells
shed by the digestive tract.
|
| By 12 weeks,
upper limb length
has nearly reached its final
proportion to body size.
The lower limbs take longer
to attain their
ultimate proportions.
|
| With the exception of the back
and the top of the head,
the body of the entire fetus
now responds to light touch.
|
| Sex-dependent developmental
differences
appear for the first time.
For instance, female fetuses
exhibit jaw movement
more frequently than males.
|
| In contrast to the withdrawal
response seen earlier,
stimulation near the mouth
now evokes
a turning toward the stimulus
and an opening of the mouth.
This response is called
the "rooting reflex"
and it persists after birth,
helping the newborn find
his or her mother's nipple
during breastfeeding.
|
| The face continues to mature
as fat deposits begin
to fill out the cheeks
and tooth development begins.
|
| By 15 weeks, blood-forming
stem cells arrive
and multiply in the bone marrow.
Most blood cell formation
will occur here.
|
| Although movement begins
in the 6-week embryo,
a pregnant woman first
senses fetal movement
between 14 and 18 weeks.
Traditionally, this event
has been called quickening.
|
