What are the other changes during puberty?

Puberty is often a time of rebellion, in which familiar things, such as rules in the family, are questioned. Due to hormonal changes in the body, young people undergo emotional instability. Friends and people of the same age become very important. They are torn between being the glamour of being independent and the risk of leaving a secure life. Unfortunately, at this time peer pressure poses a grave danger of getting into conflicts and addictions—such as alcohol or drugs.

 


Do only boys undergo a voice change?

Girls also undergo a voice change, but it is not as pronounced as in boys. The larynx in the throat is responsible for the voice and the vocal cords are present inside it. In children, the vocal chords are short, so that the voice is rather shrill. During puberty, the larynx grows rapidly in boys and one can clearly see it, the ‘Adam’s apple’, in the centre of the throat.


Continue reading "Do only boys undergo a voice change? "

How does the body change?

The production of sex hormones results in the growth of breasts in girls, a broadening of the hips, and the start of menstruation. In case of boys, the body becomes more muscular, testes and penis increase in size, the production of semen starts, and the night ejaculations begin. This is the time for first loves and understanding sexual orientation. A lot of activity goes on in the brain too. New nerve paths arise, and old ones disappear. 

What happens at puberty?

Puberty starts at about 11 or l2 years of age for girls and around 13 years for boys. This is a phase of development, in which the body and the mind undergo a change. Growth spurts, the production of sex hormones start, girls experience their first menstruation, and boys experience the breaking of their voices. Boys and girls start discovering their own sexuality and emotions run high. The transition from childhood to the adult phase is a special time and has different meanings in different cultures.

 


Why are some babies disabled at birth?

The causes of disabilities are many and cannot always be explained. We do know that a lack of oxygen at birth can cause damages to the brain. If the mother smokes or takes drugs during pregnancy, it can have serious consequences because the drug reaches the blood circulation of the child via the umbilical cord. Sometimes, there may be genetic changes which may cause disabilities. For instance, a change in the 21st chromosome causes Down syndrome in the child. It is important to ensure that people with disabilities are not discriminated against in our society. 

How does the baby breathe in the uterus?

A baby does not need to breathe in the uterus. Everything that it needs for its growth is provided to it by its supply line: the umbilical cord. This cord connects the blood circulation of the child with that of the mother. The foetus, as the unborn child is called, gets nutrients and oxygen through the umbilical cord. The waste products of the foetus are thrown out into the blood circulation of the mother and are excreted by the mother. After the birth of the baby, the umbilical cord is no longer required and is cut off. 

What determines whether a baby is a boy or a girl?

The sex of the baby is determined by the chromosomes. Usually, all of us have 23 pairs of chromosomes. They determine how our body looks like and how it works. They are also the reason we resemble our parents. The 23rd pair of chromosomes is different in case of males and females. In a woman, these are two X chromosomes, in a man it is one X and one Y chromosome. The egg cell has an X chromosome; the sperm could have either an X or a Y chromosome. If a sperm with a ‘Y’ chromosome fertilizes the egg, then the chromosome combination for the baby would be XY: a boy. If an ‘X sperm’ fertilizes the egg, the result is XX: a girl. It is clear, therefore, that the sex of the baby is determined by the father.

 


What happens to the fertilized egg cell?

A new life can start with the fusion of the sperm and the egg, which contains the genetic information of the father and the mother in equal parts. On the way through the fallopian tube, the egg cell divides several times. It finally gets lodged in the mucous membrane of the uterus, a special hollow muscle. This has a good blood supply and provides the egg cell with nutrients. After it is fixed in the uterus, the egg cell is called an embryo and development starts immediately.

How does fertilization occur?

After a man and a woman have had sex, about 300 million sperm cells are present in the woman’s vagina. The sperms swim forward with the help of their tails with a common aim: to fertilize the egg cell. The egg cell ripens in the ovary of a woman only once a month. Certain hormones then trigger ‘ovulation’, in which the egg cell is released from the ovary in the fallopian tube. Fertilization occurs if the egg cell meets a sperm. Doctors assume that after ovulation, an egg cell can be fertilized for a maximum of 12-24 hours. A single sperm cell is enough to fertilize the egg cell. 

How are babies born?

When a man and a woman have sex, the erect penis of the male is inserted into the vagina of the female. The sperm cells of the male are ejaculated into the vagina of the female. If an egg cell has been released in the ovary at that time, it may get fertilized by the sperm and the woman may become pregnant. The baby develops in the woman's uterus for about 40 weeks, till it is developed enough to be born. Usually, babies are born healthy, but sometimes they may be born with a disability.

Why must we sleep?

We may not know exactly why we need to sleep, but we do know that our body needs sleep to rest and recover. If the sleep is inadequate, performance of the brain and the body goes down. One becomes irritable and cannot concentrate. After several days of inadequate sleep, one may start hallucinating. The duration of sleep needed depends on the person and the age. While most babies sleep for more than 12 hours a day, some old people need only 5-6 hours of sleep.

 


What is a stroke?

A stroke is a serious medical condition occurring as a result of an interruption in the supply of oxygen to the brain. The most frequent reason for a stroke is the blockage or bursting of a blood vessel in the brain. In both cases, the blood circulation and, hence, the supply of oxygen to the brain is interrupted. The result is damaged brain tissue. Stroke patients may lose all information that was stored in the damaged area and may have to relearn simple things like walking, swallowing, or writing. Sometimes, the brain can build new connections between the brain cells and repair the damage. 





 

What is memory?

It is the store of things learned and retained from our activity or experience. Our memory is a collection of knowledge, experiences, impressions, skills, habits, and many other things. It gives us the ability to learn and adapt from previous experiences as well as to build relationships. It has a lifelong storage capacity, and no computer of the world can match its performance. Short-term memory is the information that we are currently thinking of and it lasts for only a few seconds. Important things which we have experienced and would not like to forget are transferred from short-term memory into long-term memory.

How do nerve cells transmit signals?

Signal transmission through nerve cells is quite complicated. Like all the other cells, nerve cells also have a cell body with a nucleus. There are fine extended branches known as dendrites and a long ‘tail’ called the axon on the body of the nerve cells. Axons in the brain are smaller than 1 mm, whereas in the spinal cord they can be as long as 1 m. A chemical substance is released through an electrical impulse into the synapses present at the end of the axon. This chemical substance, known as the neurotransmitter, is transferred to the dendrite of another nerve cell and the signals are transmitted. 





 

What is the structure of our brain?

The brain is made up of two halves. Different areas of the brain have different functions. All nerve cells in the brain, about 100 billion of them, are connected to one another and transmit information. This network of the nerve cells is expanded through learning and training. Our brain controls our actions, regulates our sleep, and allows us to feel sensations like pain and joy. If it is damaged, maybe due to a stroke, one has to relearn a lot of things like speaking, walking, or eating.