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Multilingual Illustrated DVD [Tutorial]
The Biology of Prenatal Development
Table of Contents
- THE EMBRYONIC PERIOD (THE FIRST 8 WEEKS)
- EMBRYONIC DEVELOPMENT: THE FIRST 4 WEEKS
- Chapter 3 – Fertilization
- Chapter 4 – DNA, Cell Division, and Early Pregnancy Factor (EPF)
- Chapter 5 – Early Stages (Morula and Blastocyst) and Stem Cells
- Chapter 6 – 1 to 1 1/2 Weeks: Implantation and Human Chorionic Gonadotropin (hCG)
- Chapter 7 – The Placenta and Umbilical Cord
- Chapter 8 – Nutrition and Protection
- Chapter 9 – 2 to 4 Weeks: Germ Layers and Organ Formation
- Chapter 10 – 3 to 4 Weeks: The Folding of the Embryo
- EMBRYONIC DEVELOPMENT: 4 TO 6 WEEKS
- Chapter 11 – 4 Weeks: Amniotic Fluid
- Chapter 12 – The Heart in Action
- Chapter 13 – Brain Growth
- Chapter 14 – Limb Buds and Skin
- Chapter 15 – 5 Weeks: Cerebral Hemispheres
- Chapter 16 – Major Airways
- Chapter 17 – Liver and Kidneys
- Chapter 18 – Yolk Sac and Germ Cells
- Chapter 19 – Hand Plates and Cartilage
- EMBRYONIC DEVELOPMENT: 6 TO 8 WEEKS
- Chapter 20 – 6 Weeks: Motion and Sensation
- Chapter 21 – The External Ear and Blood Cell Formation
- Chapter 22 – The Diaphragm and Intestines
- Chapter 23 – Hand Plates and Brainwaves
- Chapter 24 – Nipple Formation
- Chapter 25 – Limb Development
- Chapter 26 – 7 Weeks: Hiccups and Startle Response
- Chapter 27 – The Maturing Heart
- Chapter 28 – Ovaries and Eyes
- Chapter 29 – Fingers and Toes
- THE 8-WEEK EMBRYO
- THE FETAL PERIOD (8 WEEKS THROUGH BIRTH)
- Chapter 37 – 9 Weeks: Swallows, Sighs, and Stretches
- Chapter 38 – 10 Weeks: Rolls Eyes and Yawns, Fingernails & Fingerprints
- Chapter 39 – 11 Weeks: Absorbs Glucose and Water
- Chapter 40 – 3 to 4 Months (12 to 16 Weeks): Taste Buds, Jaw Motion, Rooting Reflex, Quickening
- Chapter 41 – 4 to 5 Months (16 to 20 Weeks): Stress Response, Vernix Caseosa, Circadian Rhythms
- Chapter 42 – 5 to 6 Months (20 to 24 Weeks): Responds to Sound; Hair and Skin; Age of Viability
- Chapter 43 – 6 to 7 Months (24 to 28 Weeks): Blink-Startle; Pupils Respond to Light; Smell and Taste
- Chapter 44 – 7 to 8 Months (28 to 32 Weeks): Sound Discrimination, Behavioral States
- Chapter 45 – 8 to 9 Months (32 to 36 Weeks): Alveoli Formation, Firm Grasp, Taste Preferences
- Chapter 46 – 9 Months to Birth (36 Weeks through Birth)
|By 24 weeks
the eyelids reopen
and the fetus exhibits
a blink-startle response.
This reaction to sudden,
typically develops earlier
in the female fetus.
|Several investigators report
exposure to loud noise
may adversely affect
increased heart rate,
excessive fetal swallowing,
and abrupt behavioral changes.
Possible long-term consequences
include hearing loss.
|The fetal respiratory rate
can rise as high
as 44 inhalation-exhalation
cycles per minute.
|During the third
trimester of pregnancy,
rapid brain growth consumes
more than 50% of the energy
used by the fetus.
Brain weight increases
between 400 and 500%.
|By 26 weeks
the eyes produce tears.
The pupils respond to light as early as 27 weeks. This response regulates the amount of light reaching the retina throughout life.
|All components required
for a functioning sense
of smell are operational.
Studies of premature babies
reveal the ability
to detect odors
as early as 26 weeks
Placing a sweet substance in the amniotic fluid increases the rate of fetal swallowing. In contrast, decreased fetal swallowing follows the introduction of a bitter substance. Altered facial expressions often follow.
|Through a series
of step-like leg motions
similar to walking,
the fetus performs somersaults.
|The fetus appears less wrinkled as additional fat deposits form beneath the skin. Fat plays a vital role in maintaining body temperature and storing energy after birth.|
|By 28 weeks the fetus
between high- and
|By 30 weeks, breathing movements
are more common
and occur 30 to 40% of the time
in an average fetus.
|During the last 4 months of pregnancy, the fetus displays periods of coordinated activity punctuated by periods of rest. These behavioral states reflect the ever-increasing complexity of the central nervous system.|
|By approximately 32 weeks,
or air "pocket" cells,
begin developing in the lungs.
They will continue to form
until 8 years after birth.
|At 35 weeks the fetus
has a firm hand grasp.
|Fetal exposure to various substances appears to affect flavor preferences after birth. For instance, fetuses whose mothers consumed anise, a substance which gives licorice its taste, showed a preference for anise after birth. Newborns without fetal exposure disliked anise.|
|The fetus initiates labor
by releasing large amounts
of a hormone called estrogen
and thus begins the transition
from fetus to newborn.
Labor is marked by powerful contractions of the uterus, resulting in childbirth.
to birth and beyond,
human development is dynamic,
continuous, and complex.
New discoveries about
this fascinating process
increasingly show the vital
impact of fetal development
on lifelong health.
As our understanding of early human development advances, so too will our ability to enhance health - both before and after birth.