Conception to Death Our bodies are ever changing from the moment we are conceived to the

moment we die. Our bodies have many different functions that help to keep us alive

every single day. We don’t think much about all our bodies do; yet everything we do

affects our bodies in some way shape or form, although we really don’t have much

control of our bodies while we are inside of the womb. So many things happen from

conception to death so why don’t we start from the beginning and go to the end.

In the beginning during the fertilization period our father’s sperm fertilizes

our mothers egg by attaching itself to the egg. Then the sperms nucleus merges with

the egg and combines genetic material, which makes the baby the perfect mix

between the mother and father. If the sperm carries a y chromosome then the baby

will be a boy and if the sperm carries an x chromosome then the baby will be a girl.

The fertilized egg, now called a zygote, then travels up the fallopian tubes and into

the uterus where it will call home for the next 40 weeks or so. While the zygote is on

its way through the fallopian tube it will divide into 16 cells. When the zygote has

entered the uterus the cells are now referred to as morula, and it proceeds to make

itself at home in the uterus by burrowing into the lining of the uterus. The cells are

now called blastocysts by scientists and they have an inner cell mass that is the

embryo itself, a fluid filled cavity that is the amniotic sac, and outer cell mass that is

the placenta. By week three the little ball of 16 cells has multiplied tremendously

and is now a ball of several hundred cells that is still continuing to grow.

Starting at four weeks into the creation of the baby’s cells it enters a period

known as the embryonic period. From now until about week 10 the organs begin to

form and even function! At this time, four weeks gestation, the baby is only about

the size of a poppy seed and consists of two layers called the epiblast and the

hypoblast where the organs and body parts will develop. At about five weeks the

baby is now approximately the size of a sesame seed and resembles a tadpole more

than an actual baby. At this time the baby is made up of three layers called the

ectoderm, the mesoderm, and the endoderm which later make up the organs and

tissues. The neural tube, where the spinal cord, brain, nerves and backbone sprout

off of, is now forming in the ectoderm. The ectoderm also gives rise to the skin, hair,

nails, mammary and sweat glands, and tooth enamel. The mesoderm is beginning to

form the heart and circulatory system and also this week the heart has begun to

separate into four chambers and beat. The mesoderm will also form the baby’s

muscles, cartilage, bone and subcutaneous tissue. The endoderm has the lungs,

intestines, and rudimentary urinary system, as well as the thyroid, liver, and

pancreas. In week six the baby begins developing the eyes, nose, and a mouth. Also

at this time the baby’s heart is beating at about 100 to 160 beats per minute. Along

with the development of the eyes, nose, and mouth the baby has little arm and leg

buds forming and his ears are only small indentations on the side of the baby’s head.

The pituitary gland is also forming at this time and so are the brain, muscles and

bones. Around this time the baby is about a quarter of an inch long.

During week seven the baby is developing hand and feet, and the tail that

made the baby look like a tad pole is becoming smaller and smaller. There are also

now eye folds that are forming a cover over the eyes, as well as the nose and tiny

veins beneath the skin. The brain has continued to grow and the liver is churning

out red blood cells until the bone marrow takes over. The pancreas and liver are

now present and the intestines are connected to the umbilical cord. During week

eight webbed fingers and toes begin poking out from the baby's hands and feet, the

eyelids practically cover the eyes, breathing tubes extend from the throat to the

branches of the developing lungs, and the"tail" is just about gone. In the brain, nerve

cells are branching out to connect with one another, forming primitive neural

pathways.

At nine weeks the baby is now about an inch long. The essential body parts

are all accounted for although they aren’t quite ready for the real world and the

heart has stopped dividing into its four chambers. Next up the heart begins to form

the valves and the sex organs have now become part of the external body even

though they aren’t quite yet distinguishable. The eyes are now fully formed but they

wont open for another couple until the baby is about 27 weeks along. Also at this

time the eyes, nose and mouth have become more distinct as well as the ears. By

week ten the baby has now completed the most critical portion of its development.

This is the beginning of the so-called fetal period, a time when the tissues and

organs in his body rapidly grow and mature. The baby is swallowing fluid and

kicking up a storm. Vital organs — including his kidneys, intestines, brain, and liver
(now making red blood cells in place of the disappearing yolk sac) — are in place

and starting to function. The baby's limbs can bend now. Its hands are flexed at the

wrist and meet over its heart, and its feet may be long enough to meet in front of its

body. The outline of its spine is clearly visible through translucent skin, and spinal

nerves are beginning to stretch out from the baby’s spinal cord.

The baby is almost fully formed by week eleven. Its hands will soon open and

close into fists, tiny tooth buds are beginning to appear under the gums, and some of

the bones are beginning to harden. At week twelve reflexes develop, the eyes have

moved from the sides to the front of the head, and the ears are right where they

should be. During week thirteen fingerprints have formed on the baby's tiny

fingertips, the veins and organs are clearly visible through the baby’s still-thin skin,

and the body is starting to catch up with the head — which makes up just a third of

the body size now. If the baby is a girl, she now has more than 2 million eggs in her

ovaries. At week fourteen the baby can now squint, frown, grimace, pee, and

possibly suck its thumb! Also the arms will have grown to a length that's in

proportion to the rest of its body.

During week fifteen the baby is moving amniotic fluid through its nose and

upper respiratory tract, which helps the primitive air sacs in the baby’s lungs begin

to develop. Its legs are growing longer than its arms now, and the baby can move all

of its joints and limbs. Although the baby’s eyelids are still fused shut, it can sense

light. Also at this time the baby is forming taste buds. This is also the earliest time

that you can determine gender. At week sixteen the heart is now pumping about 25

quarts of blood each day, and this amount will continue to increase as the baby

continues to develop. The patterning of the scalp has begun, though the locks aren't

recognizable yet. Also the baby has started growing toenails! During week

seventeen the baby's skeleton is changing from soft cartilage to bone, and the

umbilical cord — the lifeline to the placenta — is growing stronger and thicker. The

baby can now move its joints, and its sweat glands are starting to develop.

Week eighteen is most commonly recognized for the week to find out the

gender. Also the blood vessels are visible through the baby’s thin skin, and its ears

are now in their final position, although they're still standing out from its head a bit.

A protective covering of myelin is beginning to form around the baby’s nerves,

which is a process that will continue for a year after the baby is born. If the baby is a

girl, her uterus and fallopian tubes are formed and in place. If the baby is a boy, his

genitals are noticeable now which helps to determine the gender on the ultra sound.

Week nineteen is important because the brain is designating specialized areas for

smell, taste, hearing, vision, and touch. Some research suggests that the baby may be

able to hear voices. The kidneys continue to make urine and the hair on the scalp is

sprouting. A waxy protective coating called the vernix caseosa is forming on the skin

to prevent it from pickling in the amniotic fluid. In week twenty the baby is

swallowing more, which is good practice for the digestive system. The baby is also

producing meconium, a black, sticky by-product of digestion. This gooey substance

will accumulate in the bowels, and will be seen in the first soiled diaper, however

some babies pass meconium in the womb or during delivery.

Week twenty-one is when the baby's eyebrows and lids become present, and

if the baby is a girl, her vagina has begun to form as well. During week twenty-two

the baby’s lips, eyelids, and eyebrows are becoming more distinct, and there are tiny

tooth buds developing under the gums. Also at this time the eyes have formed, but

the irises (the colored part of the eye) still lack pigment. The pancreas — essential

for the production of some important hormones — is developing steadily at this

time and fine hair called lanugo that covers his body is growing and the deep

wrinkles on the skin, adds a padding of fat to fill them in. Over the course of week

twenty-three the blood vessels in the lungs are developing to prepare for breathing,

and the sounds that the baby's increasingly keen ears pick up are preparing it for

entry into the outside world. Loud noises are also becoming familiar by this time. At

week twenty-four the brain is growing quickly , and the taste buds are continuing to

develop. The lungs are developing "branches" of the respiratory "tree" as well as

cells that produce surfactant, a substance that will help the air sacs inflate once the

baby hits the outside world. The skin is still thin and translucent, but that will start

to change soon.

Come week twenty- five the baby has begun to exchange the long, lean look

for some baby fat. As this occurs, the wrinkled skin will begin to smooth out and the

fetus will start to look more and more like a newborn. Also at this time the baby is

growing more hair. By week twenty-six the baby's ears are better developed and

more sensitive than before. The baby is also continuing to put on baby fat. If the

baby is a boy, his testicles are beginning to descend into his scrotum, which will take

about two to three days. Week twenty-seven is cool because the baby is sleeping and

waking at regular intervals, opening and closing its eyes, and maybe even sucking its

fingers. With more brain tissue developing, the baby's brain is very active now.

While the lungs are still immature, they would be capable of functioning — with a

lot of medical help — if it were to be born now. At week twenty-eight the baby can

blink its eyes, which now have lashes. With the eyesight developing, the baby may

be able to see the light that filters in through the womb. At this time the baby is

developing billions of neurons in the brain and adding more body fat in preparation

for life in the outside world.

By week twenty-nine the muscles and lungs are continuing to mature, and

the head is growing bigger to make room for the developing brain. During week

thirty the eyesight continues to develop, though it still isn’t very good. Come week

thirty-one the baby can turn its head from side to side, and the arms, legs, and body

are beginning to plump out as needed fat accumulates underneath the skin. The

baby is also probably moving a lot, which means that the baby is active and healthy.

Week thirty-two is the start of the seven week span when the baby will gain a third

to half of its birth weight as it fattens up for survival outside the womb. The baby

now has toenails, fingernails, and real hair (or at least respectable peach fuzz). The

skin is becoming soft and smooth as the baby plumps up in preparation for birth. At

week thirty-three the baby is rapidly losing the wrinkled, alien look and the skeleton

is hardening. The bones in the skull still haven’t fused together, which allows them

to move and slightly overlap, which makes it easier for it to fit through the birth

canal. The bones don't entirely fuse until early adulthood, so they can grow as his

brain and other grow. During week thirty-four fat layers are filling the baby out,

making it rounder. The skin is also smoother than ever. The central nervous system

is maturing and the lungs are continuing to mature as well. If the baby is born now it

will be able to survive just fine with maybe just a short stay in the NICU to make

sure everything is working okay. During week thirty-five the kidneys are fully developed now, and the liver

can process some waste products. Most of the basic physical development is now

complete and the next few weeks will be spent putting on weight. Week thirty-six is

spent packing on the pounds — at the rate of about an ounce a day and the baby is

shedding most of the downy covering of hair that covered its body as well as the

vernix caseosa, the waxy substance that covered and protected the skin during the

nine-month amniotic bath. The baby swallows both of these substances, along with

other secretions, resulting in a blackish mixture, called meconium, will form the

contents of the first bowel movement. Week thirty-seven is considered full-term

meaning the baby is nice and ready to be born with minimal problems if any at all.

Come week thirty-eight the baby has a firm grasp and the organs have matured and

are ready for life outside the womb. As far as the eye color goes if the baby is born

with brown eyes, they'll likely stay brown, if it born with steel gray or dark blue

eyes, they may stay gray or blue or turn green, hazel, or brown by the time the baby

9 months old. That's because a child's irises may gain more pigment in the months

after the baby is born, but they usually won't get "lighter" or more blue. Fun fact

green, hazel, and brown eyes have more pigment than gray or blue eyes. Come week

thirty-nine the baby just continues to build a layer of fat to help control body

temperature after birth. Another fun fact is that boys tend to be slightly heavier than

girls. Also at this time the outer layers of the skin are sloughing off as new skin

forms underneath. At week forty the skull bones are not yet fused, which allows

them to overlap a bit if it's a snug fit through the birth canal during labor. This so-

called "molding" is the reason the baby's head may look a little conehead-ish after

birth. The final week is week forty-one assuming that the mother had stayed

pregnant this long. If the mother is still pregnant then she will be induced to make

the baby come out. When the baby is born the umbilical cord is cut which means that direct

attachment to the mother is severed. At this point in our lives we learn to live

independently. The systems in our body begin to function on their own and our

instincts begin to kick in from the moment we enter the world. Since entering the

baby still has to rely on its mother to keep it safe. The mother does this through her

breast milk, which is full of vitamins and nutrition to keep the baby healthy. The

baby can’t protect itself from the germs and bacteria at first but when the baby feeds

off of the mother the germs go to her and in turn she develops the immunities and

passes them to the baby through her milk.

As a newborn the baby’s hearing is the best it will ever be and as time passes

this sense will become more impaired. Eyesight on the other had is different. As a

newborn the baby’s sight is terrible but, at 2 months colors and shades can be

distinguished, at 4 months you can recognize your mothers face and at 8 months the

baby will have 20/20 vision. As the baby continues to grow it uses all of the different

senses to create memories that will last a lifetime, especially through touch. Touch is

vital to a baby because it helps them to explore and figure things out such as what is

soft and what is hard, what is hot and what is cold.

Over time our once soft, cartilaginous bones become more and more rigid in

order to support our ever changing lifestyle. The stronger bones are key in our

development as they help with crawling and standing, which then leads to walking.

Another important factor to walking is balance. Balance comes from within the ears,

to be more specific it comes from tiny tubes inside of the ear that are full of fluid.

As we continue to grow our bones get stronger, we lose our milk teeth, and just live life as a normal little kid enhancing our skills, and get bigger. Unfortunately this stage in our lives doesn’t last forever as the time has come for puberty. Puberty generally begins around the age of eleven. Puberty is when the pituitary gland begins to secret hormones, and send messages to the brain telling it to activate the hormones that activate other hormones. Estrogen is the sexual drive hormone for women and testosterone is sexual drive hormone for men. When men hit puberty their hair growth and their muscle mass both double all the while the vocal chords are spread apart to give a deeper voice. Puberty is the process that helps to transform young girls and boys into the young men and women that they will become. Thankfully after the awkward teenage years comes the fantastic twenties. When we are in our twenties are bodies are in the best shape both inside and out because our bodies have completely renewed themselves both inside and out. This renewal process happens every ten years. At this stage in our lives it is important for us to maintain a healthy life style by working out and eating foods that are good for the body. At the same time we should also prevent long lasting damage to vital parts of our bodies ,such as the ears. By not listening to super loud music you can prevent the loss of hearing from happening for much longer than the person that constantly blasts their music. Also in our twenties is the time when we find “the one”. Interestingly our attraction to a significant other is just as much biological as it is physical, visual or smell related. Unknowingly our bodies secrete pheromones that are picked up by the brain of each person when there is an attraction to one another. These pheromones also help the brain to decipher if the person has good genes to pro create with. Then comes marriage and soon after a baby of their own. Another thing that happens as we grow older and have kids is that the body becomes less and less like it was when we first started and eventually it stops fixing itself. Stress is another factor that contributes to the aging process. When a person is going through stress the blood vessels constrict making it harder for the heart to pump blood through them as well as receive blood from them. Continued stress causes the heart to weaken which could lead to a heart attack. As we continue to age wrinkles become more prominent, and our skin begins to sag because of the lack of elasticity between our skin cells. At the same time our vision becomes more impaired and so does our hearing. The reason our vision becomes impaired is because the lenses have become less lubricated causing them to stiffen and not adjust to light as well as they had in the past. No matter how old or saggy we get our lives will always be remembered in those that we touched the most and we will leave a legacy. Whether that legacy is good or bad is up to us and how we live our lives today while we are young.