Brain

The brain is made up of millions of nerve cells, and is part of the nervous system. It is shaped like a mushroom, and the ‘cap’ is called the cerebrum, with a very folded surface.

The cerebrum receives messages from all our sense organs, sorts them out and sends off appropriate responses. It also allows us to think, speak and remember things, as well as allowing us to have feelings and emotions.

The ‘stalk’ of the mushroom is called the brain stem, and the most important part of this is the medulla, which controls our life support systems such as breathing and the beating of our heart, without us having to think about it.

Sticking out of the brain stem is the cerebellum (which is located in the back of your head). This controls our sense of balance and allows our movements to be smooth and accurate.

This scan of the brain the head was made by an MRI scanner – that stands for Magnetic Resonance Imaging.

It shows a single scan right down the middle of the head, and some of the main blood supplies show up in lighter grey and white.

Image credit: Newcastle University

Another brain scan shows all the blood supply vessels – veins, arteries, capillaries.

The more blood that is flowing towards an area of the brain, the harder that part is working. This is one way we can work out which part of the brain does what.

Image credit: Newcastle University



MR scanners are so common now, they have their own emoji!
Image Credits: Newcastle University

This SOMSO® model from Adam,Rouilly shows the interior of the skull, especially the brain, one slice from the front and the other from the side. These same views are also shown in the MRI scans from Newcastle University that were used on Tanno and Iguda’s postcard from the brain.




Our brains keep on growing until we are about 18 years old.

A human brain is made up of over one hundred billion nerve cells.

This SOMSO® model from Adam,Rouilly shows the interior of the skull, especially the brain, one slice from the front and the other from the side. These same views are also shown in the MRI scans from Newcastle University that were used on Tanno and Iguda’s postcard from the brain.

In this video all about the brain, they use the phrase ‘encephalic trunk’ instead of ‘brain stem’. In America, encephalic trunk is a common way to talk about the brain stem.


Activity

Measuring reaction times. In this activity, your eyes send a message to your cerebrum that the ruler is falling. The cerebrum then sends a message to your hand to catch the ruler. It all happens so fast!

This requires a partner
1) Hold a ruler vertically in the air. This should be as long as possible, at least 30cm in length.
2) Your partner places their hand at the bottom of the ruler, in line with the zero mark, ready to catch it between their index finger and thumb.

Your partner should let you know that they are ready.
3) Without warning, release the ruler and let it drop – your partner must catch it as quickly as possible as soon as they see it fall.
4) Repeat this so you have ten results, and take an average score.
Swap roles, so that your partner drops the ruler and you catch it.

You can vary this experiment by comparing your left hand and right hand, is there a difference? Does the score change as you get more used to the activity – does practice make perfect?

Extension

You can work out the actual time of the reaction by using the table below. Compare the number on the ruler where the fingers caught it with the time taken.

distance (cm)Reaction time (seconds)distance (cm)Reaction time (seconds)
10.045160.181
20.064170.186
30.078180.192
40.090190.197
50.101200.202
60.111210.207
70.120220.212
80.128230.217
90.136240.221
100.143250.226
110.150260.230
120.156270.235
130.163280.239
140.169290.243
150.175300.247

You can go to the previous PostcardsFromTheBody secret pages by clicking the places below.

MouthStomachSmall Intestine
Photo of PostcardFromThe Mouth
Large IntestineBloodHeart
Lungs