The Brain

In the beginning of the lesson, we talked about our project. We learned that the due date was postponed to December 31st which was a great relief. I was really afraid that I would not be able to finish my work on time so learning that we have like about a month more to work on it made me feel really good.

Later, we started a new topic, the “brain”. Although it might be very boring to learn about the brain for many people, I like it. When I was in high school, my favourite science subject was biology and I had studied the brain in English so I didn’t have a hard time understanding this lesson.

First, we started talking about the neurons. A neuron is the basic unit of the nervous system. It receives and transmits messages. It contains dendrytes, cell body and axon. We learned that axon-dendryte connections are very few in children. Then we learned something called the myelin sheath which is covering the axon. The lack of myelin sheath causes inefficiency in the brain because if there is no myelin sheath, the signal is lost. The lack of it also causes MS. Then we talked about neurotransmitters. We said that they transmit the signal from one neuron to the next. Antidepressants work on the neurotransmitters. Some examples are endorphin, serotonin. Then we talked about the synapse and the synaptic cleft.



Moreover, we said that children are born with very less myelin sheath. Then there are two developments:
1) Myelination: A 2 year old can’t really focus on one thing: she passes playing from one toy to the other, jumping from one activity to the other. This is because there is not much myelination. However when she becomes 6 years old, she can focus. But we also added that myelination is small in teenagers.
2) Neural connections increase: Till age 3, children can easily learn second languages. Later, there is pruning. Pruning means that if certain neuroconnections are not being used, the brain will eliminate them. So pruning causes loss of neural pathways/connections. There is also redundancy.

Then we talked about the parts of the brain. There are two hemispheres in the brain and they are connected by the corpus callosum. The parts of the brain are brain stem, cerebellum, limbic system and cerebral cortex.

An interesting thing I learned in this lesson was that the brain is folded to contain more information. I also learned that fish don’t have cerebral cortex.

The cerebrum/cerebral cortex is the part which makes us important. Here are the four parts and their functions:
Frontal lobe: reasoning, planning speech…
Occipital lobe: vision
Temporal lobe: hearing, memory
Parietal lobe: touch, smell, taste

Another interesting thing I learned in this class which I haven’t learned in my previous biology lessons was that teenagers don’t have an entirely matured frontal lobe which makes them think it’s okay for drinking and driving. The most interesting thing was the story about the railroad worker who got shot in the head and his personality changed.