BRAIN FACTS
1.
3 = the weight of your brain
in pounds
2.
4 to 6 = the number of minutes
your brain can survive without oxygen before it starts to die
3.
8 to 10 = the number of
seconds you have before losing consciousness due to blood loss
4.
10 to 23 = the number of watts
of power your grain generates when you’re awake (that’s enough to turn on a
light bulb!)
5.
20 = the percentages of oxygen
and blood flow going to the brain
6.
100,000 = the number of miles
of blood vessels in your brain
7.
1,000 to 10,000 = the number
of synapses for each neuron in your brain
8.
100 billion = the number of
neurons in your brain
9.
Women are twice as likely to
be diagnosed with depression than men in the United States.
10. The human brain has about 100,000,000,000 (100 billion)
neurons.
11. A women from Berlin Germany has had 3,110 gallstones
taken out of her gall bladder.
12. From all the oxygen that a human breathes, twenty percent
goes to the brain.
13. People who ride on roller coasters have a higher chance
of having a blood clot in the brain.
14. Once a human reaches the age of 35, he/she will start
losing approximately 7,000 brain cells a day. The cells will never be replaced.
15. It is not possible to tickle yourself. The cerebellum, a
part of the brain, warns the rest of the brain that you are about to tickle
yourself. Since your brain knows this, it ignores the resulting sensation.
16. In America, the most common mental illness is Anxiety
Disorders.
17. Your brain is 80% water.
18. Your brain is move active and thinks more at night than
during the day.
19. The diameter of an individual brain neuron is just 4
microns thick, you could fit 30,000 neurons on the head of a pin.
20. Your brain generates nearly 25 watts of power while
you're awake, which is enough to light up a light bulb.
21. Alcohol interferes with brain processes by weakening
connections between neurons.
22. Every time you have a new thought, or recall a memory, a
new brain connection is made between two or more brain cells.
23. A living brain is so soft you could cut it with a table
knife.
24. Loss of oxygen for just 5 to 10 minutes can cause serious
brain damage. The brain can stay alive for 4 to 6 minutes without oxygen. After
that cells begin die.
25. The average adult's brain weighs 3 - 4 lbs. but consumes
20% of the bodys oxygen supply.
26. The human brain contains around 400 miles of blood
vessels.
27. There is no sense of pain within the brain itself which
explains why brain surgeons can probe areas of the brain even when the patient
is awake.
28. The left side of your brain (left hemisphere) controls
the right side of your body; and, the right side of your brain (right
hemisphere) controls the left side of your body.
29. Your cerebral cortex is about as thick as a doctors
tongue depressor and it grows thicker as you learn more.
30. You will lose consciousness in 10 seconds after the loss
of blood supply to the brain.
31. Of all creatures on earth humans have the most complex
brain.
32. Differences in brain weight and size do not equal
differences in mental ability.
33. If stretched out the cerebral cortex would be 0.23 sq. m
or 2.5sq.ft.
34. Average surface area of the cerebral cortex is 2,500 cm2
or 2.69 sq.ft.
35. There are about 100 billion neurons in the human brain,
the same number of stars in our galaxy.
BRAIN QUESTIONS AND ANSWERS
1.What is the Brain?
ANS-The brain is the center of
the nervous system in animals. All vertebrates, and the majority of
invertebrates, have a brain. Some "primitive" animals such as
jellyfishes and starfishes have a decentralized nervous system without a brain,
while sponges lack any nervous system at all.
In vertebrates, the brain is
located in the head, protected by the skull and close to the primary sensory
apparatus of vision, hearing, balance, taste, and smell. The human brain appears
to have no localized center of conscious control. The brain seems to derive
consciousness from interaction among numerous systems within the brain.
The human brain controls the
central nervous system by way of the cranial nerves and spinal cord the
peripheral nervous system and regulates virtually all human activity. The brain
is made up of over 100 billion nerve cells with each brain cell connected to
around 10,000 other cells, which equals around 1000 trillion connections in
your brain. Your brain is actually very soft, jelly-like, and not grey but a
deep red in color.
The brain controls both involuntary, or
"lower," actions, such as heart rate, respiration, and digestion.
Complex, or "higher," mental activity, such as thought, reason, and
abstraction, is consciously controlled.
LOBES OF CEREBRUM
2.How long is the spinal cord
and how much does it weigh?
ANS-The average spinal cord is 45
cm long in men and 43 cm long in women. The spinal cord weighs approx. 35
grams.
3.What size is an adult humans
brain?
ANS-The human brain is about the
size of a cantaloupe.
Average brain width = 140 mm
Average brain length = 167 mm
Average brain height = 93 mm
4.How much oxygen does the
brain need to stay "conscious"?
ANS-An adults brain requires
around 20% of the body's oxygen.
5.How much does the brain
weigh?
ANS-The human brain weighs on
average three pounds, or 1.5 kg.
6.How much blood is needed by
the brain?
ANS-Approximately 20% of the blood
flowing from the heart is pumped to the brain. The brain needs constant blood
flow in order to keep up with the heavy metabolic demands of the neurons.
7.Does the brain work at the
Speed of Light?
ANS-No, far from it. Axons, the
long output connection from a cell, come in two types: myelinated and
unmyelinated. Myelinated axons have an extra layer of "insulation," a
fatty substance, which allows the impulse to travel about 10 to 100 meters per
second. Unmyelinated axons only transmit at about 1 meter per second. When the
signal reaches the end, it has to cross the synapse to influence the next cell,
which adds about 5 ms. 10 meters per second = 22.356 mph and 100 meters per
second = 223.561 mph. As you can see it is a lot slower than the speed of light
in a vacuum which is exactly 299,792,458 metres per second, or 186 000 miles
per second, or 670,616,629 mph.
8.What is the largest part of
the brain?
ANS-The biggest part of the brain is the cerebrum which makes
up 85% of the brain's weight. The cerebrum is the thinking part of the brain
and it controls your voluntary muscles. 9.What are studies of the brain called?
The study of the brain and its
functions is known as neuroscience.
Psychology is the scientific
study of the mind and behavior.
Neurophysiology is the study
of normal healthy brain activity.
Neurology and psychiatry are
both medical approaches to the study of the mind and its disorders and
pathology or mental illness respectively.
10.How many main parts to the
brain are there?
ANS-The human brain can be divided
into three main parts: the forebrain, midbrain, and hindbrain:
A.The forebrain includes the
several lobes of the cerebral cortex that control higher functions.
B.Midbrain functions include
routing, selecting, mapping, and cataloguing information, including information
perceived from the environment and information that is remembered and processed
throughout the cerebral cortex.
C.Hindbrain -
(rhombencephalon) is a developmental categorization of portions of the central
nervous system in vertebrates. A rare disease of the rhombencephalon, "rhombencephalosynapsis"
is characterized by a missing vermis resulting in a fused cerebellum. Patients
generally present with cerebellar ataxia.
11.What is a neuron?
ANS-A neuron is a nerve cell in
the brain. The human brain is made up of approximately 100 billion
(100,000,000,000) neurons.
12.Is the brain an organ?
ANS-The brain is an organ as it
controls the functions of the body. It is sometimes referred to as a muscle of
thinking as the brain actually tells your muscles what to do. The brain is the
most important organ in the body because it controls all of the bodily
functions as well as the other organs.
13.Do men have a larger brain
than women?
ANS-Male humans have about a 10%
larger brain than females. A study of 46 adults aged 22-49 years found an
average brain volume of 1273.6cc for men, ranging from 1052.9 to 1498.5cc, and
1131.1cc for women, ranging from 974.9 to 1398.1cc. However differences in male
and female brain weight and size do not mean differences in mental ability.
There is evidence of a gradual increase in average brain size over the last
centuries, estimated to have been around 0.5% per decade.
14.Is a computer smarter than
a human brain?
ANS-The brain has a processing
capacity of 0.1 quadrillion instructions per second. The fastest super computer
in the world, called Roadrunner is capable of handling 1.026 quadrillion
calculations per second. However the computational power of the human brain is
difficult to ascertain, as the human brain is not easily paralleled to the
binary number processing of computers. For while the human brain is calculating
a math problem, it is subconsciously processing data from millions of nerve
cells that handle the visual input of the paper and surrounding area, the aural
input from both ears, and the sensory input of millions of cells throughout the
body. The brain is also regulating the heartbeat, monitoring oxygen levels,
hunger and thirst requirements, breathing patterns and hundreds of other
essential factors throughout the body. It is simultaneously comparing data from
the eyes and the sensory cells in the arms and hands to keep track of the
position of the pen and paper as the calculation is being performed.
15.Can an adult grow more
brain cells?
ANS-A landmark study in late 1998
by researchers from Sweden and the Salk Institute in La Jolla, California,
showed for the first time that some brain cells in mature humans may regenerate
under certain circumstances.
16.Do humans only use 10% of
the brain?
ANS-No, we use all of our brain.
17.What are Neurodegenerative
diseases?
ANS-Neurodegenerative diseases,
such as Alzheimer’s diseases,Parkinson’s diseases, motor neurone disease, and
Huntington's disease are caused by the gradual death of individual neurons,
leading to decrements in movement control, memory, and cognition.
18.Does alcohol kill brain
cells every time you drink?
ANS-The idea that alcohol kills
brain cells has long been promoted. Drinking alcohol does not actually
"kill" brain cells. Roberta Pentney, professor of anatomy and cell
biology at the University at Buffalo, concludes that alcohol does not kill
brain cells but it damages the dendrites, the branched ends of nerve cells that
bring messages into the brain cell causing damage to the way the cells in the
brain communicate. Luckily the damage is largely reversible and not permanent.
However years of alcohol abuse can cause serious neurological damage, including
Wernicke-Korsakoff syndrome.
19.In what part of the brain
do you get brain tumors?
ANS-BRAIN TUMORS are classified depending on the exact site of
the tumor, the type of tissue involved, benign or malignant tendencies of the
tumor, and other factors. Primary (true) brain tumors are commonly located in
the posterior cranial fossa in children and in the anterior two-thirds of the
cerebral hemispheres in adults, although they can affect any part of the brain.
20.How are memories stored and
retrieved?
ANS-nfortunately we don't yet
comprehend exactly how this happens or how memories are recalled years later
for retrieval.
SOME DEFINITIONS
Consciousness:
A constellation of attributes
of mind such as subjectivity, self-awareness, sentience, and the ability to
perceive a relationship between oneself and one's environment.
Unconsciousness:
An alteration of mental state
that involves complete or near-complete lack of responsiveness to people and other
environmental stimuli. Being in a comatose state or coma is an illustration of
unconsciousness. Fainting due to a drop in blood pressure and a decrease of the
oxygen supply to the brain is an illustration of a temporary loss of
consciousness.
1.How and why do we dream?
ANS-Dreams have fascinated nearly
everyone for thousands of years. There are two different schools of thought as
to why we dream: the physiological school, and the psychological school. While
many theories have been proposed, not single consensus has emerged as to why we
dream. Some researchers suggest that dreams serve no real purpose, while other
believe that dreaming is essential to mental, emotional and physical
well-being. One theory for dreaming suggests dreams serve to clean up clutter
from the mind.
2.Are humans born with all
their brain cells?
ANS-Babies are born with around a
100 billion brain cells, but only a small number of neurons are actually
connected. By three years of age a childs brain has formed about 1,000 trillion
connections, about twice as many as adults have. At around 11 years, the brain
begins to prune unused connections. Connections that are used repeatedly in the
early years become permanent; those that are not are eliminated. Hence the
saying, "use it or lose it."
3.How does the brain control
body temperature?
ANS-The Hypothalamus part of the
brain regulates body temperture much like a thermostat. The hypothalamus knows
what temperature your body should be (about 98.6 Fahrenheit or 37 Celsius), and
if your body is too hot, the hypothalamus tells it to sweat. If you're too
cold, the hypothalamus makes you start shivering. Shivering and sweating helps
get your body's temperature back to normal.
4.How and why do we sleep?
ANS-We still don't fully
understand the importance of sleep however we do know that sleep is the time
when the body does most of its repair work; muscle tissue is rebuilt and
restored and tissure building growth hormone is secreted during sleep. A good
way to understand the role of sleep is to look at what happens when we don't
get enough sleep.
5.Are IQ tests accurate
measures of intelligence?
ANS-First you need to define
intelligence, a very hard task, think about it. Intelligence is an encompassing
term. "We cannot measure intelligence when we have not defined it"
said journalist Walter Lippmann in the early 1920's. According to most current
definitions intelligence is made up of the skills of logical reasoning, problem
solving, critical thinking, and adaptation.
IQ tests are not very reliable
and the scores may vary as much as 15 points from one test to another. The
average IQ scores for many populations have been rising at an average rate of
three points per decade since the early 20th century with most of the increase
in the lower half of the IQ range.
6.Do brain supplements work in
enhancing memory and brain power?
ANS-As we age our brain is more
susceptible to memory loss and diseases such as Alzheimer's disease. The
functionality of the human brain can also be affected due to problems in
nervous system or inadequate blood supply to the brain. Here are few brain
supplements
said to assist the brain.
7.When is the brain considered
dead?
ANS-Brain death is the
irreversible end of all brain activity (including involuntary activity
necessary to sustain life) due to total necrosis of the cerebral neurons
following loss of blood flow and oxygenation. A brain-dead individual has no
clinical evidence of brain function upon physical examination. This includes no
response to pain and no cranial nerve reflexes. Reflexes include pupillary
response (fixed pupils), oculocephalic reflex, corneal reflex, no response to
the caloric reflex test and no spontaneous respirations. The diagnosis of brain
death needs to be rigorous to determine whether the condition is irreversible.
Legal criteria vary, but it generally requires neurological exams by two
independent physicians. The exams must show complete absence of brain function,
and may include two isoelectric (flat-line) EEGs 24 hours apart.
If tests show brain activity,
the patient may be in a coma or vegetative state. A brain dead person doesn't
show brain activity. It is important to distinguish between brain death and
states that may mimic brain death. Some comatose patients can recover, and some
patients with severe irreversible neurologic dysfunction will nonetheless
retain some lower brain functions such as spontaneous respiration, despite the
losses of both cortex and brainstem functionality. Thus, anencephaly, in which
there is no higher brain present, is generally not considered brain death,
though it is certainly an irreversible condition in which it may be appropriate
to withdraw life support.
Today, both the legal and
medical communities use "brain death" as a legal definition of death.
Using brain-death criteria, the medical community can declare a person legally
dead even if life support equipment keeps the body's metabolic processes working.
No comments:
Post a Comment