By 4 weeks the clear amnion surrounds the embryo in a fluid-filled sac.[55] This sterile liquid, called amniotic (am-nē-ot'ik) fluid, provides the embryo with protection from injury.[56]

The heart typically beats about 113 times per minute.[57] The heart changes color as blood enters and leaves its chambers with each beat. The heart will beat approximately 54 million (5.4×107) times before birth and over 3.2 billion (3.2×109) times over the course of an 80-year lifespan.[58]

Rapid brain growth is evidenced by the changing appearance of the forebrain, midbrain, and hindbrain.

Upper and lower limb development begins with the appearance of the limb buds by 4 weeks.[59]

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.[60]

Between 4 and 5 weeks, the brain continues its rapid growth and divides into five distinct sections.[61]

The head comprises about one-third of the embryo's total size.[62]

The cerebral (ser'ĕ-brăl) hemispheres appear,[63] gradually becoming the largest parts of the brain.[64]

Functions eventually controlled by the cerebral hemispheres include thought, learning, memory, speech, vision, hearing, voluntary movement, and problem-solving.[65]

Lord, we marvel as we read about the development of this little child. The heart, the limbs, the brain are all developing according to the plan you put in place at fertilization, and we can hardly keep track of the speed of all that is happening.

O God, free us from the error of thinking that size determines value. Instead, help us to discover the wonder of small things, and of small people.

Protect all children as they grow in the womb, and open our minds to what science teaches us about how we all developed in our earliest weeks.

We pray through Christ our Lord. Amen.

By 4 weeks the clear amnion surrounds the #embryo in a fluid-filled sac. This sterile liquid, called amniotic (am-nē-ot'ik) fluid, provides the embryo with protection from injury. If an embryo is not human why is there a natural protection from injury? See more at babychris.org

With #heartbeatbill being passed in many states think about this fact: The heart beats about 113 times per minute. The heart changes color as blood enters & leaves its chambers with each beat. The heart will beat 54 million times before birth. See more @babychris.org

In the developing embryo rapid brain growth is evidenced by the changing appearance of the forebrain, midbrain, and hindbrain. It doesn’t take a scientist to know if the embryo has a brain it’s more than a blob of tissues. See more at babychris.org

At 4-5 weeks cerebral hemispheres appear, gradually becoming the largest parts of the brain. Functions controlled by the cerebral hemispheres include thought, learning, memory, speech, vision, hearing, voluntary movement, & problem-solving. See more at babychris.org

We continue to track the development of Baby Chris in the womb, at BabyChris.org.

On April 22, Baby Chris turns four weeks old. Chris’ heart is beating about 113 times per minute, upper and lower limb development has already begun, and rapid brain growth is occurring. This week, the brain will divide into five distinct sections, and the baby’s head will comprise about one third of the baby’s total size.

It is amazing to see so much activity and growth in a child just a little over one eighth of an inch tall!