Unit 4 P1 -Human Lifespan - Conception and Development

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Assignment 1

The Human Lifespan


Conception is the whole process of conceiving or becoming pregnant. There are four stages of conception; copulation, fertilization, gestation, and birth. Copulation is the act of having sexual intercourse or could be done by IVF (In Vitro Fertilization) which is when an egg is mixed with a sperm in a glass and put back in the woman’s uterus. First, the ovaries release eggs into the uterus then the egg gets fertilized. When the sperm meets the egg and gets inside the egg, it gets fertilized and turns into ‘zygote’. After it turns into a zygote, it embeds itself in the lining of the blood vessels in the womb. Then the woman becomes pregnant.

 Copulation is the first step to conception. Every month, the ovaries release eggs to the uterus through the fallopian tube where it remains for 3 days. Ovulation is the term used when ovaries release eggs. When the man and woman have sexual intercourse, the man releases millions of sperms into the woman’s uterus. 

The next stage is fertilization; it’s when the sperm meets the egg. Only one sperm succeeds in fertilizing an egg. When it is fertilized, it is then called a ‘zygote’, it becomes embedded to the lining of the blood vessels in the womb and then the woman becomes pregnant. The zygote gets divided, a process called ‘cell division’, after the first division it is then called an embryo. The embryo keeps dividing until it cannot be divided any more. When it finishes dividing the last cell divided forms a shape and eventually a foetus.

Sometimes the sperm doesn’t meet the egg in the womb, sometimes it meets in the fallopian tube. It’s called ‘ectopic pregnancy’. If they meet in the wrong place like the fallopian tube and the baby grows there, it could be very painful for the woman carrying the child and their fallopian tubes could tear causing internal bleeding which could lead to feeling faint and losing consciousness.

Gestation is when the foetus develops into a baby. Gestation takes 9 months, more or less. There are three month periods called trimesters of the physical development of a zygote. The first trimester is when the foetus still looks like a baby lizard. You can start recognizing its head, spinal column and cord on its back, and a very visible umbilical cord running along its front stomach attached to the mother. When the baby is still in its first trimester, it is legally allowed to get an abortion. But when it’s on its second trimester, 4-6 months it’s no longer allowed, but can still be done illegally. When it is 4-6 months old, the foetus starts to form its arms, legs, facial features and other body parts. When it gets to it third and final trimester, it finally fully develops the body parts and the baby is now recognizable. And then the mother gives birth to the baby.

When the zygote turns into an embryo after cell division it is the size of a pinhead. This 'cell division' happens after 3 days of pregnancy. By the third week of pregnancy the embryo would already have a recognizable head and a spinal column and cord on its back and an umbilical cord attached to the wall of the mother's placenta which is located in the uterus. By the fourth week the fore brain of the embryo's fore brain develops where the head becomes more rounded. The body becomes C-shaped, grows its tail, and the cells that become the heart starts to move. When it's on its eighth week the embryo would be 3-4cm long. It would have a recognizable heart beat and slowly develop its eyes, mouth and other body parts so it begins to look more human. On its 2 – 7th month the internal organs will be developing and reach half the length or height of a fully developed baby and will reach half of the full weight only by its 8th month. On the last and 9th month, the baby's weight and height gets doubled because this is when the mother is feeding and consuming a lot of food. And then eventually, the mother gives birth to the child which can either be naturally born or by caesarean section which is when they cut open the stomach so the baby can be taken out but only when the mother is not able or having difficulty pushing the baby out through the womb.


        The term development refers to complex changes; it results in improved skills and abilities. Infancy development includes physical changes like growth – in height and weight. It also includes how the person develops intellectually – how they think and understand, emotionally – how it feels and socially – how they act around people.

        A person may develop normally, or they could have disabilities. They could suffer from arrested development which means that their physical or mental development is stopped, arrested that could be caused by genes or the environment. An example of arrested development would be when a person doesn’t grow physically, but they can grow mentally like dwarves. A person could also have delayed developmental issues; their development being delayed. A child could be mute for the first few years, but then suddenly they talk like a normal person would. Developmental delay could also be caused by genes or the environment.

INFANT (0 – 3 years old)

Physical Developments

        New-borns have reflexes like startle reflex, walking reflex, rooting reflex, and grasp reflex. The startle reflex (or 'Moro' reflex) is when you make loud noises or when you raise its head and lowering it suddenly, the baby will throw its legs and arms out, wiggle and also cry a little. Sometimes they do this in their sleep; they get woken up by the startle reflex. Some babies can go back to sleep but some babies can't and that's why some babies keep crying and parents have to take care of them in the middle of the night and make them fall asleep again. They grow out of this reflex between 3-7 months.

Walking reflex is when you carry the baby by its underarms with their feet almost touching the ground; the baby will start doing motions and kick its legs that make it look like they're walking. The only do this in their first and second months. The rooting reflex is when you stroke the baby's cheek with your breasts or fingers and the baby turns its head that way and makes sucking motions like when the mother tries to breastfeed their babies. The baby usually only does this when it's only 0-4 months old.

        Grasp reflex is when the baby grasps things like when you stroke your finger on its palm, the baby clasps its hand around your finger. The baby will also do the same if you stroke its feet, they will curl up. This gradually fades in its 3-4th month. 

When they’re aged 0-2 years they get breastfed by their mothers, it helps their bones and muscles develop. For the first few months of a baby, it is not able to balance its head as the muscles and bones in the neck are not properly developed but as it grows older, it is then capable to move and turn its head whichever way it wants to and we wouldn't have to hold its head for support. The development is called 'motor development', when the child slowly develops their bones and muscles and are able to move around. When the baby is newly born it is still fragile that's why people are very careful when carrying them but as months pass, the bones grow not only longer but also stronger so they can stand on their own.

There are two types of motor development, the gross motor and the fine motor. The fine motor development is involving the small muscles that are found in our hands while the gross motor is the development of the larger muscles like the ones found in our arms and thighs and all over our bigger organs. At the age of at least 1 year, they start learning how to walk, hold things and point and move their body parts however.

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The child also grows teeth, they grow on their first few weeks but they come out of the tooth buds and show their first 2 front teeth usually the ones in the middle, between 4-7 months. They eventually grow out a full set of teeth usually when they reach their third birthday. Permanent teeth come out only when they are fully grown replacing the baby teeth. The baby's gum would swell and get sensitive, behaviour would also change, experience sleeping problems and they would often drool resulting to rash on the face.

When a baby is born, it has ...

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