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Multilingual Illustrated DVD [Tutorial]

The Biology of Prenatal Development

4 - 6 Weeks

Introducing the Multilingual Illustrated DVD
Explore the fascinating imagery and facts presented in The Biology of Prenatal Development at your own pace. Each clip from the program is accompanied by its corresponding written script. Select Play Movie to watch any clip. Select See Snapshots to view high resolution images. See the program script and subtitles in 88 languages by using the Choose Language drop-down menu and clicking Refresh. Subtitles are displayed in your chosen language and may be turned on and off by clicking the button found in the lower right corner of the movie player. A "full screen" option is also available by clicking the button.

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Show Table of Contents


Embryonic Development: 4 to 6 Weeks Chapter 11 4 Weeks: Amniotic Fluid

Play Movie \| See Snapshots	By 4 weeks the clear amnion surrounds the embryo in a fluid-filled sac. This sterile liquid, called amniotic fluid, provides the embryo with protection from injury.
Chapter 12 The Heart in Action

Play Movie \| See Snapshots	The heart typically beats about 113 times per minute. Note how the heart changes color as blood enters and leaves its chambers with each beat. The heart will beat approximately 54 million times before birth and over 3.2 billion times over the course of an 80-year lifespan.
Chapter 13 Brain Growth

Play Movie	Rapid brain growth is evidenced by the changing appearance of the forebrain, midbrain, and hindbrain.
Chapter 14 Limb Buds

Play Movie \| See Snapshots	Upper and lower limb development begins with the appearance of the limb buds by 4 weeks.
Play Movie \| See Snapshots	The skin is transparent at this point because it is only one cell thick. As the skin thickens, it will lose this transparency, which means that we will only be able to watch internal organs develop for about another month.
Chapter 15 5 Weeks: Cerebral Hemispheres

Play Movie \| See Snapshots	Between 4 and 5 weeks, the brain continues its rapid growth and divides into 5 distinct sections. The head comprises about 1/3 of the embryo's total size. The cerebral hemispheres appear, gradually becoming the largest parts of the brain. Functions eventually controlled by the cerebral hemispheres include thought, learning, memory, speech, vision, hearing, voluntary movement, and problem-solving.
Chapter 16 Major Airways

Play Movie \| See Snapshots	In the respiratory system, the right and left main stem bronchi are present and will eventually connect the trachea, or windpipe, with the lungs.
Chapter 17 Liver and Kidneys

Play Movie \| See Snapshots	Note the massive liver filling the abdomen adjacent to the beating heart. The permanent kidneys appear by 5 weeks.
Chapter 18 Yolk Sac and Germ Cells

Play Movie \| See Snapshots	The yolk sac contains early reproductive cells called germ cells. By 5 weeks these germ cells migrate to the reproductive organs adjacent to the kidneys.
Chapter 19 Hand Plates and Cartilage

Play Movie \| See Snapshots	Also by 5 weeks, the embryo develops hand plates, and cartilage formation begins by 5 1/2 weeks. Here we see the left hand plate and wrist at 5 weeks and 6 days.