Science, Art, Litt, Science based Art & Science Communication

Qs people asked me on science and my replies to them - part 268

Q: While playing volleyball I fall and got injured but I didn't tell anyone because I wanted to play but now it's painful to move that hand I think my shoulder bone moved a bit from it's place I'm 14 can repair by itself what should I do?

Krishna: No, a dislocated shoulder will not heal itself. If you suspect a dislocated shoulder, seek prompt medical attention. Most people regain full shoulder function within a few weeks. However, once you've had a dislocated shoulder, your joint may become unstable and be prone to repeat dislocations.

The shoulder joint is the most frequently dislocated joint of the body. Because it moves in several directions, your shoulder can dislocate forward, backward or downward, completely or partially, though most dislocations occur through the front of the shoulder. In addition, fibrous tissue that joins the bones of your shoulder can be stretched or torn, often complicating the dislocation.

Shoulder dislocation is a common injury in contact sports, such as football and hockey, and in sports that may involve falls, such as downhill skiing, gymnastics and volleyball.

Complications of a dislocated shoulder may include tearing of the muscles, ligaments and tendons that reinforce your shoulder joint, nerve or blood vessel damage in or around your shoulder joint, shoulder instability, especially if you have a severe dislocation or repeated dislocations, which makes you more prone to re-injury.

If you stretch or tear ligaments or tendons in your shoulder or damage nerves or blood vessels around your shoulder joint, you may need surgery to repair these tissues.

If you notice a visibly deformed or out-of-place shoulder, swelling or bruising, intense pain, or inability to move the hand/joint, go to a good qualified medical doctor immediately. Don’t neglect.

To avoid a recurrence, follow the specific strength and stability exercises after consulting your doctor.

Q: What is the science behind a person becoming a righty or a lefty?

Krishna: In human biology, handedness is an individual's preferential use of one hand.

There are various theories with regard to handedness. The science regarding handedness is incomplete and not settled yet.

Handedness research in the twentieth century produced not only promising pathways of understanding but also a number of dead ends. The heavy dependence on incidence rate studies produced extended controversies and rampant inconsistencies in the attempts to connect left-handedness to both pathological and nonpathological traits.

Genetic factors, epigenetic factors, prenatal hormone exposure, even ultrasound [ theory is that ultrasound may sometimes affect the brains of unborn children, causing higher rates of left-handedness in children whose mothers receive ultrasound during pregnancy - research suggests there may be a weak association between ultrasound screening (sonography used to check the healthy development of the fetus and mother) and left-handedness (3)] are all considered to understand the handedness.

The mapping of the human genome and the ability to scan specific genetic sites will eventually lead to a new understanding of the genetics underlying human handedness and brain asymmetry. Neural imaging techniques with both human and primate participants have already revealed previously unknown aspects of brain asymmetries. A good example of this latter point is the research that scanned the brains of natural right-handers and left-handers converted to right-hand writing while both groups wrote with the right hand. The brain activation patterns of the two groups while writing were not identical. The former left-handers retained residual activation in the movement centers of the right hemisphere that was not seen in the brains of natural right-handers. These results confirmed the theory that switching the writing hand from left to right produces changes in the brain. However, it contradicted the claim that these brain changes are dysfunctional for the person involved (1).

Research since the 1980s has shown that our preference for being left or right-handed is probably determined in the womb before we are born, as early as the eighth week of pregnancy, according to ultrasound scans. From week 13 in the womb, babies tend to suck either their right or their left thumb.

It was previously thought that the genetic differences in the left and right hemisphere of the brain would determine whether someone was born left or right handed. But a study from 2017, published in the journal eLife, has found that the answer could lie in the spinal cord.

They found that gene activity in the spinal cord is already asymmetrical in the womb, and this could be what causes left or right-handedness.

Arm and hand movements start in the brain, in an area called the motor cortex, which sends a signal to the spinal cord. This is where the signal is translated into a motion. While the baby is growing in the womb, up until about 15 weeks, the motor cortex and the spinal cord are not yet connected, but right or left-handedness is already decided.

In other words, the baby can already make movements, and has chosen its favourite hand before the brain starts controlling the body. This led the researchers to believe the spinal cord is the decider for the hand preference.

The asymmetrical nature of the spinal cord could be down to something called epigenetics - which is how organisms are affected by changes in their genes' expressions, rather than in the genes themselves. These changes are often brought about by environmental influences, and can affect how the baby grows.

These gene expression differences could affect the right and left spinal cord differently, resulting in lefties and righties.

Studies on twins show a different picture (2). It revealed genetics - the DNA inherited from parents - has some role to play. But how does it work?

The mutations were in instructions for the intricate "scaffolding" that organises the inside of the body's cells, called the cytoskeleton.Similar mutations that change the cytoskeleton in snails have been shown to lead to the molluscs having an anticlockwise or "lefty" shell.

In the left-handed participants, the two halves of the brain - the left and right hemispheres - were better connected and more co-ordinated in regions involved in language. The researchers "speculate" left-handed people may have better verbal skills, although they do not have the data from this study to prove it.

The best guess is handedness is 25% genetic and 75% down to the environment.

So the handedness science is not settled. The work to determine the exact causes is still going on.

Footnotes:

1. https://www.sciencedirect.com/topics/neuroscience/left-handedness

2. https://academic.oup.com/brain/article/142/10/2938/5556832?login=false

3. Salvesen KÅ (September 2011). "Ultrasound in pregnancy and non-right handedness: meta-analysis of.... Ultrasound in Obstetrics & Gynecology. 38 (3): 267–71. doi:10.1002/uog.9055. PMID 21584892. S2CID 5135695.

Q: How can we identify someone drowning in a swimming pool?

Krishna: There are several reports in the media about children and young adults drowning not only in swimming pools but in canals, rivers and sea.

There are a few signs,experts say, can be used to identify somebody who is drowning.

1. Bobbing or floating in place.

2. Head tilted back with mouth open.

3. Head low in the water, with mouth at water level.

4. Trying to roll over onto the back.

5. Hyperventilating or gasping for breath.

6. Hair over forehead or eyes.

7. Eyes glassy and empty, unable to focus, or eyes closed.

If someone appears to be in trouble in the water, take immediate action. Get help from others who can swim. Do not attempt to rescue a drowning person when you're also in the water unless you are trained to do so. Drowning people may panic and try to pull anyone nearby underwater with them.

Instead, extend or throw a floating object to the person. Once they are safely out of the water, tilt their head back, lift their chin and check for breath. Turn the person on their side to help them expel water.

If the person is not breathing, anyone trained should begin to perform hands-only CPR until the ambulance and paramedics arrive.

Also, keep the following steps in mind:

Always designate a responsible adult to supervise children in or near water.
Clear any loose toys from the pool area to reduce tripping hazards.
Don't use toys as flotation devices. Use life jackets for activities in or near lakes, rivers, or oceans, especially for children and weaker swimmers.
When swimming in natural bodies of water, be wary of hidden hazards such as strong currents, sharp rocks, or tangles of vegetation.
Always check the weather forecast before water activities.
Use the buddy system when swimming.
Don't drink alcohol before or during water activities or while supervising children.
People with medical conditions or those taking certain medications may require additional precautions.

Qs people asked me on science and my replies to them - part 268

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