Growth and Ageing -2 major processes that occur during growth
Table of Contents
Growth occurs as a result of changes that happen in the body. From the zygote to the fetus, to a baby, a toddler, a child, an adolescent, and to an adult, growth occurs consistently.
Merriam Webster dictionary defines growth as the natural increase in size. Growth in humans become visible as height and weight increases, and as they start gaining the ability to perform various activities over time.
When growth fails to happen normally and at the right time, it becomes a call for concern and worry.
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Growth is triggered by changes in the requirements of various parts of the body.
For instance, in the third week of fetal life, the cardiovascular system begins to grow and develop because the embryo can no longer meet its oxygen and nutritional needs by only diffusion. This is the signal that triggers growth and development of the heart and its components.
As time goes on, the requirements of the body continue to change requiring the occurrence of growth and maturation.
When a child is born newly, the child is dependent on breast milk for the first six months of life outside the womb. Within this period, breast milk is able to provide sufficient nutrient.
After six months, however, supplementary foods become necessary and the body adapts to this by making the digestive system fit enough to break down foods.
Before the end of six months, any attempt to give other foods will lead to digestive issues.
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The major processes that occur during growth are:
Cell division
The cell is the smallest unit of the body. When cells divide, it leads to an increase in the number of cells. This increase causes parts of the body to mature gradually.
There are two types of cell division: Mitosis and Meiosis.
Mitosis is called a multiplication division; in other words, the cells multiply by dividing.
Meiosis is called a reduction division, because the cells do not multiply in this case, but retains a constant number.
Meiosis occurs in reproductive organ cells, while mitosis occurs in every other cell.
In bones for instance, as cell division occurs, the bone lengthens, leading to a visible increase in height. Substances are deposited in the bone which makes it stronger. This process is known as ossification.
Cell growth and maturation
As cells are formed, they grow subsequently, and then die, so that new ones can be formed.
Cell growth involves the increase in the size of cells and their adaptability to many functions.
In red blood cells (erythrocytes) for instance, the cells continue to increase in size, haemoglobin is formed, and other cell organelles disappear.
After its life span of 120 days, it is destroyed in the spleen.
Ageing
Ageing simply means growing older. It is a natural part of the growth that presents with loss of hair, weakness of bones, wrinkling and folding of skin, etc.
Some of the factors responsible for ageing include:
Age
Over time, the body cells continue to wear off as age sets in. Some processes no longer occur as smoothly as they used to.
As we age, the cells in our bodies get to a point where division ceases and then breakdown begins.
For instance, as one grows older, fat cells in the body begin to atrophy (reduce). These fat cells are responsible for the smooth texture of the skin. As these fat cells atrophy, the skin begins to fold, and wrinkles begin to appear.
2. Genetics
The effect of age may be more visible in some individuals than in others. While some people will grow white hair earlier in life, some will happen later in life.
Someone who already has an eye defect in his/ her earlier years of life is more prone to have a declining sight when they grow older.
Additionally, a family history of diseases such as hypertension, cancer, or diabetes, makes one more prone to these diseases that occur majorly in old age.
3. Environmental factors
Environmental factors include food, water, and surroundings.
People, who eat unhealthy foods more often, age faster.
Exposure to sun rays is another feature that enhances ageing. UV ray from the sun can lead to mutations, hence bringing the onset of ageing closer.
4. Health status
Some diseases like cancer make people look older; because it alters many normal functions in the body. Autoimmune diseases destroy cells of the body more quickly, leading to loss of weight and more changes that come with the advancement in age.
