脑细胞的五大杀手 （ZZ)# LeisureTime - 读书听歌看电影
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在另外一贴看到说脑是一个复杂的器官，无独有偶，看到这新闻，就转一下。就不翻译
了。
5 Ways You're Killing Your Brain Cells
http://www.msn.com/en-us/health/medical/5-ways-youre-killing-yo
Contrary to popular belief, we don’t have a limited supply of brain cells.
Sure, the majority of them grow early in life, but some areas of the brain
continue to grow them into adulthood and beyond — a process called
neurogenesis. The hippocampus is one of these areas, and it’s also among
the most important areas of the brain, playing roles in memory, emotion, and
learning. But as we grow older, a number of factors compete with
neurogenesis and kill brain cells. No, they’re not smoking weed and
drinking alcohol; instead, they’re a little more common than you might
expect. Here are seven of them.
1. Losing Sleep
The National Sleep Foundation recommends most adults get between seven and
nine hours of sleep every night, and for good reason. This gives our brains
sufficient time to move through the sleep stages, which gradually become
deeper, and end in REM (rapid eye movement) sleep before starting all over
again.
Getting to REM sleep is important because it’s during this time that the
brain is working hard both to keep us asleep — by causing paralysis in
limbs during dream states, for example — while also activating brain
regions responsible for learning. This is when memories are consolidated and
stored, and energy levels are replenished. With that said, it’s not
surprising that someone who consistently loses sleep will have a harder time
concentrating, making decisions, and engaging themselves in both learning
and social situations.
A study from last year shows how these effects fall in line with brain
damage; it found the neurons in the energy-producing region of the brain
called the locus coeruleus (LC) began to die from extended wakefulness.
Without these cells to produce energy, our bodies are unable to function
properly the next day. Another study found sleep deprivation could cause
shrinkage in the cerebral cortex and hippocampus, especially in adults over
60 years old, suggesting that sleep becomes ever more important as we age.
2. Smoking
Over 42 million adults smoke cigarettes in the United States; that’s nearly
one in five people. And with each drag, they’re inhaling over 7,000 toxic
chemicals, 69 of which have been shown to cause cancer. Smoking causes a
whole range of other diseases, too, from chronic bronchitis to emphysema, to
heart disease and stroke.
Stroke, in itself, has been shown to cause brain damage, but with all these
toxins, there’s bound to be at least one that specifically affects the
brain, right? It turns out there are several of them. In a 2002 study from
France’s National Institute for Health and Medical Research, scientists
found nicotine-addicted rats generated 50 percent fewer neurons in the
hippocampus’s dentate gyrus. Those that took higher doses of nicotine also
experienced the most brain cell death. If that isn’t bad enough, another
study from India found a compound in cigarettes, called NNK, could cause an
exaggerated response in the brain’s white blood cells, forcing them to
attack healthy brain cells as well.
Researchers from the rat study believe their findings could explain why
smokers who try to quit experience short-term cognitive problems. “It could
be that while they are smoking, the stimulant effect of nicotine masks the
loss of neuronal plasticity,” study author Pier Piazza told New Scientist.
“When they stop smoking, these deficiencies remain.”
3. Dehydration
The common misconception that alcohol will kill brain cells comes from the
fact that it triggers a whole range of body processes. One of these is “
breaking the seal”; that moment when we have to use the bathroom after
downing a couple of beers, and revisiting it more often than usual for the
rest of the night. As we drink more, the alcohol suppresses the hormone
vasopressin, which is responsible for retaining water in the body. This
makes our bodies unable to hold our urine in, and one unfortunate result is
dehydration — which also happens to be the reason we get hangovers.
Considering 75 percent of the brain is made of water, it would behoove
anyone drinking to couple their vodka-cranberry with a large glass of water.
Actually, we’re going to recommend that glass of water being around at all
times of the day, because mild dehydration can occur after only four hours.
Once it starts getting bad, it can cause the brain to swell (cerebral edema
) as the body tries to pull more water into the cells — some of these may
eventually rupture. Seizures aren’t uncommon either, as electrolyte
imbalances cause neurons to miscommunicate. All of this causes the brain to
work harder to function properly, which in turn can cause it to shrink, a
2011 study found.
4. Stress
Most of us can agree there’s been that one day or week where everything
seemed to be going wrong. Trying to juggle so many problems is stressful.
But because it’s the body’s way of rising to the challenge, it often helps
us with improved concentration and focus. However, the body can only take
so much of it, and after a certain point, it’ll backfire, throwing off
concentration, causing irritability, and killing our energy.
All of this can be blamed on the stress hormone cortisol, which is released
from the adrenal gland during stressful moments. The hormone activates
several biological processes with the intention of diverting energy to where
it’s most needed; digestion, for example, stops while heart rate increases.
In people with chronic stress, however, cortisol levels can be so excessive
that the brain ends up producing more myelin-producing cells and fewer
neurons, a study from last year found. Myelin is the fatty material that
makes up the brain’s white matter and quickens communication between
neurons. But such changes in the brain, the researchers said, may contribute
to a person’s risk of mental health illnesses like schizophrenia and
anxiety disorder.
5. Cocaine and Other Narcotics
While marijuana won’t kill brain cells, other narcotics on the Drug
Enforcement Administration’s drug schedule list certainly will. Drugs like
cocaine, methamphetamine, bath salts (synthe8 things your doctor's not
telling youtic cathinones), and MDMA (ecstasy or molly) all activate the
brain’s reward systems, triggering the release of the neurotransmitters
serotonin, dopamine, and norepinephrine.
While triggering all these neurotransmitters can cause a euphoric high and
make the user especially active, they also damage the neurons responsible
for releasing the feel-good chemicals. As a result, the user can develop a
tolerance to the drug, which forces them to take more over time to achieve
the same high — further damaging the cells or even killing them. In a 2003
study on cocaine, researchers looked at brain samples from 35 deceased
cocaine users and compared them to the brains of 35 nonusers. They found
dopamine levels were far lower in those who had used cocaine, especially in
those who were depressed as well, suggesting that there were fewer dopamine-
producing neurons.
Researchers believe that this damage to brain cells is what leads to drug
addiction, as the user finds it progressively harder to feel good on his own
.
了。
5 Ways You're Killing Your Brain Cells
http://www.msn.com/en-us/health/medical/5-ways-youre-killing-yo
Contrary to popular belief, we don’t have a limited supply of brain cells.
Sure, the majority of them grow early in life, but some areas of the brain
continue to grow them into adulthood and beyond — a process called
neurogenesis. The hippocampus is one of these areas, and it’s also among
the most important areas of the brain, playing roles in memory, emotion, and
learning. But as we grow older, a number of factors compete with
neurogenesis and kill brain cells. No, they’re not smoking weed and
drinking alcohol; instead, they’re a little more common than you might
expect. Here are seven of them.
1. Losing Sleep
The National Sleep Foundation recommends most adults get between seven and
nine hours of sleep every night, and for good reason. This gives our brains
sufficient time to move through the sleep stages, which gradually become
deeper, and end in REM (rapid eye movement) sleep before starting all over
again.
Getting to REM sleep is important because it’s during this time that the
brain is working hard both to keep us asleep — by causing paralysis in
limbs during dream states, for example — while also activating brain
regions responsible for learning. This is when memories are consolidated and
stored, and energy levels are replenished. With that said, it’s not
surprising that someone who consistently loses sleep will have a harder time
concentrating, making decisions, and engaging themselves in both learning
and social situations.
A study from last year shows how these effects fall in line with brain
damage; it found the neurons in the energy-producing region of the brain
called the locus coeruleus (LC) began to die from extended wakefulness.
Without these cells to produce energy, our bodies are unable to function
properly the next day. Another study found sleep deprivation could cause
shrinkage in the cerebral cortex and hippocampus, especially in adults over
60 years old, suggesting that sleep becomes ever more important as we age.
2. Smoking
Over 42 million adults smoke cigarettes in the United States; that’s nearly
one in five people. And with each drag, they’re inhaling over 7,000 toxic
chemicals, 69 of which have been shown to cause cancer. Smoking causes a
whole range of other diseases, too, from chronic bronchitis to emphysema, to
heart disease and stroke.
Stroke, in itself, has been shown to cause brain damage, but with all these
toxins, there’s bound to be at least one that specifically affects the
brain, right? It turns out there are several of them. In a 2002 study from
France’s National Institute for Health and Medical Research, scientists
found nicotine-addicted rats generated 50 percent fewer neurons in the
hippocampus’s dentate gyrus. Those that took higher doses of nicotine also
experienced the most brain cell death. If that isn’t bad enough, another
study from India found a compound in cigarettes, called NNK, could cause an
exaggerated response in the brain’s white blood cells, forcing them to
attack healthy brain cells as well.
Researchers from the rat study believe their findings could explain why
smokers who try to quit experience short-term cognitive problems. “It could
be that while they are smoking, the stimulant effect of nicotine masks the
loss of neuronal plasticity,” study author Pier Piazza told New Scientist.
“When they stop smoking, these deficiencies remain.”
3. Dehydration
The common misconception that alcohol will kill brain cells comes from the
fact that it triggers a whole range of body processes. One of these is “
breaking the seal”; that moment when we have to use the bathroom after
downing a couple of beers, and revisiting it more often than usual for the
rest of the night. As we drink more, the alcohol suppresses the hormone
vasopressin, which is responsible for retaining water in the body. This
makes our bodies unable to hold our urine in, and one unfortunate result is
dehydration — which also happens to be the reason we get hangovers.
Considering 75 percent of the brain is made of water, it would behoove
anyone drinking to couple their vodka-cranberry with a large glass of water.
Actually, we’re going to recommend that glass of water being around at all
times of the day, because mild dehydration can occur after only four hours.
Once it starts getting bad, it can cause the brain to swell (cerebral edema
) as the body tries to pull more water into the cells — some of these may
eventually rupture. Seizures aren’t uncommon either, as electrolyte
imbalances cause neurons to miscommunicate. All of this causes the brain to
work harder to function properly, which in turn can cause it to shrink, a
2011 study found.
4. Stress
Most of us can agree there’s been that one day or week where everything
seemed to be going wrong. Trying to juggle so many problems is stressful.
But because it’s the body’s way of rising to the challenge, it often helps
us with improved concentration and focus. However, the body can only take
so much of it, and after a certain point, it’ll backfire, throwing off
concentration, causing irritability, and killing our energy.
All of this can be blamed on the stress hormone cortisol, which is released
from the adrenal gland during stressful moments. The hormone activates
several biological processes with the intention of diverting energy to where
it’s most needed; digestion, for example, stops while heart rate increases.
In people with chronic stress, however, cortisol levels can be so excessive
that the brain ends up producing more myelin-producing cells and fewer
neurons, a study from last year found. Myelin is the fatty material that
makes up the brain’s white matter and quickens communication between
neurons. But such changes in the brain, the researchers said, may contribute
to a person’s risk of mental health illnesses like schizophrenia and
anxiety disorder.
5. Cocaine and Other Narcotics
While marijuana won’t kill brain cells, other narcotics on the Drug
Enforcement Administration’s drug schedule list certainly will. Drugs like
cocaine, methamphetamine, bath salts (synthe8 things your doctor's not
telling youtic cathinones), and MDMA (ecstasy or molly) all activate the
brain’s reward systems, triggering the release of the neurotransmitters
serotonin, dopamine, and norepinephrine.
While triggering all these neurotransmitters can cause a euphoric high and
make the user especially active, they also damage the neurons responsible
for releasing the feel-good chemicals. As a result, the user can develop a
tolerance to the drug, which forces them to take more over time to achieve
the same high — further damaging the cells or even killing them. In a 2003
study on cocaine, researchers looked at brain samples from 35 deceased
cocaine users and compared them to the brains of 35 nonusers. They found
dopamine levels were far lower in those who had used cocaine, especially in
those who were depressed as well, suggesting that there were fewer dopamine-
producing neurons.
Researchers believe that this damage to brain cells is what leads to drug
addiction, as the user finds it progressively harder to feel good on his own
.
