Categories
WHY CORNER

Why do we stop growing after a certain stage?

When certain aquatic plants keep growing throughout their life, then why do we terrestrial animals stop growing? Well, a simple explanation is that that all animals, including humans, have evolved such that they stop growing at a size that balances energy efficiency and their competitive needs as they struggle to survive.

you may click & see

In humans, genes determine the growth pattern and height that one attains. Growth is said to occur when cells called chondroblasts multiply, adding cartilage to the ends of bones. Cells called osteoblasts then deposit calcium and other minerals in the cartilage and turn it into new bone tissue. As the deposition of calcium and minerals goes on, bones become longer and you grow taller. Toward the end of puberty, your body produces lots of oestrogen and this inhibits chondroblast proliferation thus slowing down the addition of new cartilage to the ends of your bones. When all the cartilage in the active growth area is calcified, you stop growing.

The overproduction or underproduction of certain hormones (bio-chemicals released in our body) or the inability to respond to them can affect growth, making it above or below normal. Gigantism is caused by the overproduction of the pituitary growth hormone, whereas severe short stature is often caused by the body’s inability to respond to this and other growth hormones.

Another interesting theory to explain this issue is that terrestrial animals have to support their weight without any help. Therefore, we have been designed to stop growing to protect our bodies from becoming bigger than we can manage.

According to space researchers, if you travel into space, you will  grow irrespective of your age. Although the effect is temporary, you can actually grow by as much as eight centimetres while in orbit, they say. This is due to reduced gravitational force acting on your body. As a result, the spinal column stretches out a bit thus making one taller. This phenomenon is also visible when you are asleep. If you sleep horizontally, you will actually be a little taller in the morning since gravity is unable to compress your spinal column until you stand up.

Source:The Telegraph ,Kolkata(India)

Categories
WHY CORNER

Why do people snore while sleeping?

[amazon_link asins=’B004AH8N3A,B015DEYJJU’ template=’ProductCarousel’ store=’finmeacur-20′ marketplace=’US’ link_id=’d8dadb7a-1a10-11e7-ae5f-87c9892c8969′]

Snoring  happens  to all of us: tossing and turning sleeplessly while the person in the next room snorts and snarfs his way through the night. Why is it that a perfectly normal, healthy person makes such an awful noise?

CLICK & SEE

While breathing during sleep, structures like the palate, uvula (fleshy conical lobe at the back of the mouth) and tonsils may flap against each other as there may be excess tissue in this region. The vibration of relaxed floppy tissues that line the upper airway causes the sound that you hear when someone is snoring. This is because when you sleep, all the muscles in the body are relaxed and muscle tone decreases.

The upper airway is lined with muscles that keep the airway open. When these muscles relax during sleep, the diameter of the airway decreases and, in some people, this partially blocks the airflow, leading to turbulence.

Instead of air flowing smoothly down the airway into the lungs, it flows with gusts and bursts. Travelling through such an airway, the air picks up speed and gets whipped around in different directions. As the air bounces around, it hits the relaxed, floppy tissues lining the throat and causes them to vibrate, like a flag in the wind. This produces the snoring sound.

People don’t make a snoring sound when they are awake because the muscles in the throat hold the airway open wide enough for a smooth flow of air into the lungs.

Also, we snore more as we get older because our muscles become increasingly flaccid with age. Gaining weight also adds to the chances of snoring as fat deposits accumulate in the tissues of the airwaymaking them heavier so they fall more into the line of airflow.

Source:The Telegraph (Kolkata,India)

Categories
WHY CORNER

Why does your stomach growl when you are hungry?

[amazon_link asins=’B007XXFGU6,B009KBOST4,B076CS1H28,B00L8O19CU,1250063086,B01BTZKCC0,B00AIUUXHC,B078HL9DRT’ template=’ProductCarousel’ store=’finmeacur-20′ marketplace=’US’ link_id=’6b0a8912-8c1e-11e8-8e83-6f0c8371e3b0′]

Doctors call it “borborygmi”. Sounds somewhat like the sound you hear, isn’t it?

Growling in the stomach is a common phenomenon all of us would have experienced sometime or the other. “The stomach muscles are in constant peristaltic motion to digest the food ingested and letting it flow into the intestines. In general, increased flow within the system causes the stomach to growl,” says Dr Mahesh Goenka, director and head of the department of gastroenterology, Apollo Gleneagles, Calcutta.

The reasons for the increased flow of chyme (digested food) are many. Often, an obstruction in the gut may hamper the bowel movement, thereby causing an increased flow in the proximal region to allow smooth passage. In an attempt to do so the muscles contract vigorously, thereby causing the growling noise. The obstruction could be due to a tumour or a consequence of tuberculosis.

“Again, if in the absence of food the stomach walls squeeze together in an attempt to mix and digest food, the gases and digestive juices slosh around in the empty organ creating the noise,” says Dr Goenka.

Yet, hunger actually has nothing to do with an empty stomach but is a result of certain nutrients missing in the bloodstream. The brain contains a “hunger centre”, which functions as an accelerator — or brake — for our stomachs and intestines. Once the necessary nutrients are lacking in the blood, the dinner bell is rung and the stomach and intestines start growling.

The reasons that trigger malabsorption of nutrients often include worm infestations like gyadriasis or tropical spruce (common in India), TB, lymphoma (an intestinal tumour) or Crohn’s disease (an allergy that causes inflammation of the bowel). And, adds Dr Goenka, if you are thin and lack adequate adipose padding, then too your stomach can often be heard growling.

Source:The Telegraph (Kolkata,India)