Do I have any of the same cells as when I was born?

Do I have any of the same cells as when I was born?

Varpu Palo, 8

Stem cells are a kind of cell factories of the body that are able to divide and transform into new tasks.

Previously, it was assumed that, for example, the liver, muscles and bones would be regenerated with the help of stem cells.

Recently, however, it has been discovered that even the neurons of the brain and their supporting cells seem to regenerate at least partially.

It is known that, for example, blood cells, i.e. red and white cells and platelets, are constantly renewed, so an eight-year-old does not have the same blood cells left as when he was born.

However, it is not known for sure whether an eight-year-old or older person still has any of the same cells in his body as when he was born. Based on current knowledge, it would seem that we could still have the same stem cells.

The eight-year-old is growing at a fast pace, during which his body also produces a lot of new stem cells. In a growing child, most of the cells are very new.

Seppo Vainio

professor of developmental biology

Kvantum Institute, University of Oulu

How long does it take for a raindrop to fall from the sky to the ground?

Anna Aalto, 8

It depends about how high a raindrop’s journey starts and how big it is.

Raindrops can be of very different sizes. Small drops can be about 0.5 millimeters or the size of a mandarin, while in tropical heavy rain near the equator the drops can grow up to six millimeters or the size of a pea. According to research data, raindrops in Finland are usually smaller than three millimeters.

The drop height also varies a lot. Because we in Finland live in the cold north, the formation of rain often starts with ice crystals, which grow into snowflakes and melt as they fall into raindrops. Usually, raindrops fall from a height of about two kilometers here, but in thunderstorms the height of the clouds can be even more than 10 kilometers.

If we assume that the droplet is the size of a grain of rice, i.e. about two millimeters, and it falls from a height of two kilometers, it takes about six minutes to reach the ground.

If, on the other hand, a raindrop of the same size falls from a height of ten kilometers, it takes about 30 minutes. The wind or upward-flowing air encountered by the drop during its journey can slow down its journey somewhat.

Annakaisa von Lerber

investigator

Department of Meteorology

Why do cats and dogs chase their tails?

Viljami Merikallio, 11

Reasons there are several to chase the tail.

As young cats and dogs begin to explore their surroundings, they also find their tails. For example, kittens play with their tails to learn predatory skills specific to their species. Even if food is offered to the pet from a plate, it does not eliminate the need to chase. Playing shows that the puppy is doing well.

Sometimes interest in the tail can indicate health problems. If the tail is suffering from pain or itching, the animal will easily try to relieve it by scratching, licking or biting, although this only makes the matter worse. Then he should be examined and taken care of. When the trouble goes away, he is left alone.

Also, the lack of meaningful activities can lead to stereotypic, i.e. schematically repetitive, activities that look like chasing the tail. This occurs especially in dogs. By circling the ring with its tail behind it, the dog relieves its boredom. By increasing exercise or other fun activities, walking in a circle will decrease.

If the dog shows an almost compulsive wagging of the tail, it may be an obsessive-compulsive disorder caused by intense stress. Some individuals may have a hereditary predisposition to it. If the veterinarian confirms the diagnosis, he will also give treatment instructions.

Outi Vainio

emeritus professor of veterinary pharmacology

University of Helsinki

Where is the tallest tree in Helsinki? What about Finland?

Alvar Pfau, 7

Helsinki the longest tree is known to be a 41-meter spruce, which is located in the Pitkäkoski nature reserve.

The longest tree in Finland is the European larch from Punkaharju in Savonlinna, which has a length of 47.3 meters. Also in the village of Padasjoki Vesijao, a spruce almost as tall, 45 meters, grows.

The longest pine tree grows in the Lehmo village of Kontiolahti. It is 42 meters. Birches and aspens can grow to about 35 meters in Finland.

The information is compiled by wood enthusiasts. Some of the measurements are already quite old, so someone should update them. Results may vary slightly due to tree growth and death. Maybe not all of Finland’s tall trees have even been found yet!

Sometimes it is difficult to see the tops of tall trees in the forest because they may be shaded by other trees. In open places, trees can become multi-branched and broad-topped, in which case the highest point is not always visible either.

There is more information about tree thicknesses than lengths. Length is traditionally measured with a measure called a hypsometer. With it, you aim first at the base of the tree and then at the top, after which the length in between is calculated. New measuring devices that utilize laser beams are also available. The most accurate result can only be measured with a tape measure after the tree has been felled.

Juha Raisio

wood specialist

Dendrologian Seura ry

Send the question, the questioner’s full name and age to [email protected]. The column is provided by Touko Kauppinen.