2. 22-2
BRAIN AND NERVES
The Electrical System of Brain And Nerves
Just as you have electric wires trying to connect a switch on the wall to a electric bulb or a electric
motor, we have nerves connecting the brain to the hand or legs !
Our Brain Controls All
All that the brain has to do is to tell one Our Brain Can Sense All
part of the body to move, and small elec- The brain is more than just a switch
tric currents go from the brain to that part. to command. It also gets a second to
It orders some muscles to squeeze, the second feedback on every activity
opposite group to relax, and magically, and has to be active at all times to
the order is followed. In fact there is no make corrections.
part of the body that is not connected to
the brain. The brain is the most impor- So, you may have our eyes closed but
tant part of the body and can command it can tell if someone is standing on
the heart to slow down or beat faster, can your toes. If a 50 paise coin is kept
command the pancreas to secrete insulin
in our hand, without even looking
when we have eaten too much of sugar,
or can command the hand to move away
at it, we would be able to tell it from
when it has touched a hot plate. a one-rupee coin.
How Do You Tell A Banana From An Orange?
Fine receptors on our skin can tell a feather touch from a rough cloth, hot from cold, a pointed
needle from a solid bar and on our fingers can tell two points a mm apart. Other receptors can
make us smell a orange differently from a lemon, can taste an apple differently from a banana
and can help us make out the calls of a hundred different birds. The eyes of course are very
specialised and its receptors can report all our surroundings to our brain in the dimmest of
lights.
PARTS OF OUR NERVOUS SYSTEM
Brain
1. Brain
The Brain weighs about a kilo and a half. Present inside the skull, it
is as thick as soup or a raw egg. It is connected to every part of the
body at one place or the other, directly usually, but occasionally
indirectly also. It gets small electric signals from different parts of
the body, tries to understand them, makes sense of them and then
sends commands back to continue or alter the previous commands.
Our Brains Has Departments That Do Different Jobs
Our brain has different areas allocated to take care of different functions.
The following two diagrams show where different signals from various parts
of the body reach and where the commands for different parts of the body
are sent from.
3. 22-3
The Brain Wires Are Crossed
The wires in our brains are crossed. All right-handed people have the left side of their
brain that is ‘dominant’ (or more powerful). While in some left-handed people, the
right side of the brain is dominant.
What the Different Departments Do? Brains Need To Receive Signals
The dominant side of the brain is responsi- We would commonly ask someone who does
ble for language, and for understanding in- not pay heed to us if he is hard of hearing. The
formation in a logical sequence. The non- fact is that even though our ears may hear, un-
dominant side of the brain looks after sig- less the areas of the brain were to receive the
nals from seeing and also about the space signals properly, understand them and send
around us. The non - dominant side takes them to another part of the brain, we would
care of recognition of faces, of music, or not be able to ‘know’ what we heard. Similarly,
identification of things by their forms. even if our eyes were okay, but if the part of
If for some reason, the dominant side gets the brain towards the back was not okay, we
damaged, the person is unable to speak. But wouldn’t ‘know’ what we saw and hence even
if the other side were to be damaged, she with wide open and healthy eyes, we would
would be able to speak, but may not be able not be able to move away from a car about to
to pay attention to others emotions or her run us over!
other side of the body.
What Do Different Parts of the Brain Do?
Different parts of the Brain Front of Brain Controls
Behaviour: The front of
controls different things
the brain is associated
imagine with learning that deter-
mines how we behave. It
talk helps us plan our future
see Front Brain actions. If this part of ours
were to get damaged,
feel
probably our neighbours
hear would be shocked to hear
walk-move Middle Brain us swear abuses or see us
roaming nude! Learning
heart beat/ how to socialise is also
Lower Brain
breathing controlled here.
Lower Brain Controls Basic Body Functions : On the other hand, the lowest part of the brain
- called the brain stem, has the most important and ‘basic’ centres. Even if the top parts of the
brain were to stop functioning – only the brain stem were to function, we would be ‘alive’
because our breathing, our heart rate and our blood pressure is controlled from there.
Middle Brain Control Our Sensations: Just above the brain stem is where our body receives all
the signals that warn it about danger, like those of pain. Just below this smell and sex signals are
also understood. Temperature regulation, hunger, sleep and thirst are also controlled here. So
also are controlled here the emotions of fear and anger, and those of maternal instinct.
4. 22-4
2. Nerves
Nerves are like electrical wires that carry weak electric signals from one part of the body to an-
other. While some of them may travel all the way from the periphery to the brain in one go, some
of them may end in another nerve and then carry the signals through one or two more nerves.
Our Nervous System
Carriers of Sensations & Signals
Different types of nerves carry different signals Brain
and sensations.
a. Thick Nerves : Carry signals of
command from the brain to the peripheral Spinal Cord
organs.
b. Medium Sized Nerves: Nerves carrying
Nerves
touch and pressure
are of intermediate size.
c. Thin Nerves : The thinnest nerves are used
for carrying pain sensation.
Across the Football Field in 1 Second
!
The speed at which the sensation is carried also
Sense receptors
depends on the size of the nerve fibres. The thick- Nerves end in sense receptors which help us
est nerves carry commands from the brain as fast identify different sensations. So we are able to
as 120 metres a second, about the length of a foot- know hot, cold, pain, pleasure etc. These nerve
ball field in one second. Pain sensation usually receptors are present on our skin or muscles at
travels at 2 to 5 metres a second. various intervals.
Nerves from these sense receptors carry the sig-
nals to the brain. The brain then is able to choose
what it is to do. For example, sense receptors
on our tongue called “taste buds” tell our brain
whether what we are eating is sweet or bitter.
The brain then decides whether to continue
eating or to stop.
2. Spinal Cord Spinal
The spinal cord starts from where the brain stem ends at the skull Cord
and it goes all the way just below the chest at the back. It goes
through the hollow of the small bones of the backbone.
Nerves carrying sensations up to the brain go in front of the spinal
cord. And nerves that carry orders from brain to the body organs
are in the back portion of the spinal cord. On the sides of the cord
are a mixture of nerves that come down and those that go up. Some
nerves are long. They carry signals through long nerve fibres all
the way up or down. But most nerves are not so long. They end
halfway and pass on their signal through other nerves.
5. 22-5
Spinal Cord Injury
Signals starting from one side usu- In people whose spinal cord is cut, many of the sensations from the
ally cross over to the other side ei- brain are unable to reach the ends and signals cannot reach from the
ther after reaching the brain or some- ends to the brain.
where on the way in the spinal cord.
So, if a person were to damage her In such cases, the muscles below the cut spinal cord waste away and
spinal cord near the neck, some of get thin. Sensations are poor and the person may not even be able to
her sensations would be lost on the know when to pass shit or urine. Considerable training needs to be
same side while other sensations given to such people, and special care needs to be taken of their blad-
would be lost from the other side. der and skin, or else they develop infections and die.
AUTONOMIC NERVOUS SYSTEM
The Control System
It is the autonomic system that controls the most Autonomic system controls the most
important organs inside our body. It adjusts the important organs inside our body
heart rate, empties our stomach, squeezes out the
urinary bladder when it is full and it throws out
the man’s semen during sex. It works all by itself
like a well-oiled machine with little or no guidance
from the Brain.
Many organs are controlled together
The autonomic system of the body can carry out functions
of different organs of the body all at the same time. We can
best see this in an emergency. In an emergency, there is no
time for the body to carry out normal activities like shitting
or urinating. Then, the body could carry out a well-
coordinated ‘automatic ‘ range of actions.
The palms start sweating (to improve the grip on a mis-
sile or weapon), the eye pupils dilates to allow more
light to be able to see better and the heart would beat
harder (to prepare for exercise like running away or us-
ing the limbs). The lungs would breathe harder and
quicker to get more oxygen and the liver would release
stores of stored glucose if required.
Along with this, the speed of the intestine would slow
down and the ends of the stomach, rectum and bladder
would tighten to prevent diversion of attention to
shitting and pissing that can be done later.
6. 22-6
Know the Answers
BRAIN & NERVES
a. Please mark whether “right” ot “wrong”:
1. The brain controls all parts of the body except heart and lungs.
2. Each organ in the body sends signals to the different parts of the brain.
3. The brain sends chemical fluids through the nerves to different parts of the body.
4. The left side of the brain controls the right side of the body and the right
side controls the left side.
5. The autonomous nervous system controls the brain automatically.
b. Please tick the right answer:
The autonomic nervous system helps the body fight or take flight by affecting the working of the
following organs :
1. Lungs by breathing harder / weaker and faster / slower.
2. Eye pupils by becoming smaller / bigger.
3. Heart by beating slower / faster.
4. Liver by letting out stores of glucose / protein.
c. Please fill in the blanks:
1. The more powerful side of the brain helps us in our _______________ while the non-power
ful side of the brain helps us think of _______________ and ____________________.
2. A person with an injured spinal cord has the following problems:
a. Hand and feet ______________________
b. Bladder ___________________________
c. Sex organs ________________________
3. Nerves are of three types:
a. Thick nerves carry ________________________ sensations.
b. Medium sized nerves carry ______________________ sensations.
c. Thin nerves carry _______________________ sensations.
7. 22-7
Diseases of the
BRAIN AND NERVES
Page Number
1. Meningitis 22-8 to 22-9
2. Encephalitis or Brain fever 22-10
3. Brain stroke 22-10
4. Polio and related illnesses 22-11
5. Head injury 22-11
6. Spinal cord injury 22-12
7. Mental illnesses 22-12 to 22-13
8. 22-8
DISEASES OF THE BRAIN AND SPINAL CORD
The Brain is such an important part of the body that any disorder affecting it would affect the
person’s life very seriously. The same is about disorders of the spinal cord.
As a health worker, you will be called to deal with some diseases of the brain and spinal cord,
such as:
1. Meningitis 5. Head injury
2. Encephalitis or Brain fever 6. Spinal cord injury
3. Brain stroke 7. Mental illnesses
4. Polio and related illnesses
1. Meningitis (me-nin-jye-tis)
Membranes called meninges cover the brain to hold its porridge like mass of nerves together. Due
to infections, these meninges may swell and get inflamed. This is meningitis ans it may get severe
to lead to death.
Many types of germs may cause meningitis. Meningitis due to the TB germ and some types of
fungus have a very slow progression. However, the intensity of problems with most other
bacteria and viruses is quick and can kill without giving much time.
Usually meningitis is seen as:
The illness very often starts with a sore throat or a cold with high fever. However, other signs as
mentioned below come up rapidly and can get very serious.
1. Fever – high and at 2. Headache: The person
times with chills. How- complains of severe headache
ever, TB and some fungi and may even vomit because
can also cause meningitis of it. The vomiting is worth
that has very low fever noting because often the force
although other signs are of vomiting is very high and
present. gets thrown very far from the
body.
3. Neck stiffness: Test for Meningitis
The neck is stiff and To test further, ask the person to
one can feel it to be lie down and straighten the
so. Ask the person knees and the hip. Now try to
to touch her chin to bend forward the neck towards
her chest. She will the chest. The hips and the knees
not be able to. Even automatically tend to bend – this
if you try to force such touching, you is an important sign of meningitis.
will experience severe restriction.
9. 22-9
4. Rashes: Some 6. Fits: Any infection of the meninges also af-
children may fects the nearby brain tissues. Hence, fits or con-
show rashes on vulsions in which the person becomes uncon-
the face or chest, scious and throws about his jaws, arms and legs
but is difficult to in repetitive motions are also important signs of
see in dark peo- meningitis. especially in a person who has been
ple. complaining of headache for a few hours or
days.
5. Unconsciousness: Unconscious-
ness may appear within a few hours
of the beginning of the headache. In
TB meningitis, the period may be a
few days or weeks away.
However, if treatment is not started
Fits is also a sign of
within minutes, it may lead to death.
meningitis
Treatment for Meningitis:
A test done by removing some fluid from the lower area of the
spinal cord can tell if the offending germ is bacteria, TB or a virus.
In the last case, there is no cure.
Refer urgently any child or elder who shows headache and
neck stiffness as explained above.
If the doctor is far, start Amoxycillin or Ciprofloxacin
and ask the relatives to urgently take the patient to
a hospital. Unconscious patients may need injections.
Prevention of Meningitis
Meningitis can often spread from one person to another very fast
as can be seen in school hostels and soldiers’ barracks.
If more than one patient is seen who stay in the same room
or hall, open all windows and doors and sun the room/
hall.
Increase the distance between the beds and prevent crowd-
ing.
Those who have already been staying with the
patients may be started on Amoxycillin to prevent
meningitis.
BCG in children can help avoid TB meningitis.
10. 22-10
2. Encephalitis (en-kef-e-lye-tis) or Brain fever
Encephalitis means swelling of the brain (not just the covering!) and can lead to death. Although
signs of meningitis can be the same as that of encephalitis, the neck stiffness and headache are
considerably less in encephalitis, also called Brain fever by lay people. On the other hand, fits,
unconsciousness, inability to move one or both eyes, inability to swallow or speak or to move
her hands or legs are signs that one or more areas of the brain have been affected.
Starting with mild or high fever, cold or cough, the illness is caused only by viruses (not bacte-
ria) like that of Polio, Measles, Rabies or Herpes. As such, we still do not have any effective germ
killers that may be used easily.
Refer immediately if encephalitis
We need to provide support systems to help the per-
son survive the three to seven days period, while the
effects of the virus get over. These can be possible only
at hospitals and hence it is important to identify the
illness early enough and refer immediately to a doc-
tor/hospital.
3. Brain stroke
A Brain Stroke means that suddenly the blood supply of one or both sides of the brain has been
cut off. One or more parts of the brain stops working because of this. Usually this happens in
people above the age of forty and those known to be having high blood pressure and/or high
blood sugar (Diabetes).
How strokes happen?
It can happen by two methods.
a. In the first type, a blood clot blocks the brain’s blood b. In the second type of stroke, one
supply slowly. People can experience this type of stroke of the tubes that supply blood
in two ways. For example, an old person gets up from to the brain bursts suddenly.
sleep with an inability to speak. This keeps worsening This could be because of high
in the next few hours. He will reach a state when she blood pressure or some weak-
cannot even move her arm, then legs, etc. This usually ness in its wall. The person
happens only the left or the right side of the body, not both. suddenly loses consciousness
Unconsciousness is also typical of a stroke. and collapses. The chances of
death in such patients are
In other people, the person gets a sudden feeling of weak- very high unless they reach
ness on one side of the face or hand or leg. And this keeps and get a good standard of
worsening. Usually, if the person survives the first two days, medical care in the first few
the person gradually gets better and regains most – though hours of illness.
not all – functions of different parts of his body.
Treatment for strokes
In both the illnesses, if the person is still alive and can swallow, give
one tablet of Aspirin before sending her off to a hospital. To an un-
conscious patient, put her in the Recovery position (see First Aid of
Unconsciousness) and send her immediately to the hospital.
11. 22-11
4. Polio and related illnesses
Polio may affect the spinal cord (and brain as discussed earlier). The virus enters through
our food and water into the intestines and slowly reaches the brain and spinal cord.
There are other similar illnesses also that behave like Polio. (We will learn more about
Polio when we learn Immunisation Diseases).
There is no cure for Polio once it has attacked the body. So, children must be
given Polio drops to drink to prevent them from getting Polio.
Leg affected by
Polio virus
5. Head injury
Falls & other accidents can lead to injury of the brain inside. This is called head injury. Also, Road
Traffic Accidents (RTAs) are common and injuries to the brain can be serious enough to lead to
death.
Signs to look out for in a head injury
a. Loss of Consciousness: One of the most important b. Abnormal behaviour
things to note is loss of consciousness. Even if the person is Another important sign to
conscious when you get to see note is the presence of signs
her, if she or other people like irrelevant talking, ag-
present at the accident site say gressive behaviour, fits,
that she had lost consciousness unconsciousness, etc. Diffi-
for some time, it is serious culty in swallowing or talk-
enough. If so, ENSURE that the ing after a head injury is
person is close to a hospital /sur- another danger sign.
geon for at least 24 hours after
the accident.
There are two other signs that you can test to predict danger: If
present, SEND TO A HOSPITAL IMMEDITELY.
* Shine a torch in one eye Check for brain damage * Take a key or a blunt pointed
at a time and check the thing and rub it hard on the soles
pupil size and its move- brain of the injured person’s feet. Rub
ment. Slow movement or damage from the heel to base of the big toe
a lack of movement in (when toe via the base of the small toe. If one
the pupil is dangerous. goes up)
or both the big toes bend up-
Also, if the size of the two wards towards the head, it tells
pupils is different, it can be us that the brain signals are not
dangerous. Quickly send reaching the legs. Once again,
normal
the patient to a hospital. (when toe send the patient to the hospital at
goes down) the earliest.
IMPORTANT
Such patients may need an operation on the brain at the earliest. Do not allow them
to eat or drink anything and rush them to a hospital that has facilities for
operations.
12. 22-12
Spinal 6. Spinal cord injury
Cord The Spinal Cord may get injured if the spine or backbone gets injured in an
accident or a fall from the roof/tree. Depending on how badly the injury has
taken place, the spinal cord may be partially or fully cut.
What happens in A different kind of paralysis
spinal cord injury? Unlike the inability to move legs- paraly-
The person may be unable to sis — that can also happen in a head (brain)
move her legs. She may lose con- injury, here the legs when moved by an-
trol over her bladder and lose the other person feel like soft rubber that is
capacity to hold back her shit and loose. On the other hand, paralysis (pa –
urine. If it is a man, he may be ra- li-sis) due to head injury makes the legs
and arms very stiff when someone tries to
unable to perform sex with his
move them.
partner.
If the person does not recover any movement of the toes or feet at the end of two full days of the
injury, there is little hope for it later. In most cases however, the Spinal Cord does not get fully cut
and some movement does recover very early.
Treatment for Spinal Cord Injury
First Aid is all that one must try at the health work-
er’s level. Refer such a person to a hospital but make
sure that the person’s spine is not damaged further
while sending to a hospital. If the injury is in the
neck, place sand bags on both sides of the neck to prevent it from
turning. For lower injuries of the spine, see the section on First
Aid on Fractures.
7. Mental illnesses
If one goes by definitions provided by doctors who specialise in mental illnesses, these illnesses
are common. Three types of mental illnesses are commonly seen :
1. Anxiety (ang-zye-ti)
2. Depression (dep-re- shun)
3. Psychosis (sy-ko-sis)
1. Anxiety
Anxiety means that someone is extra worried about one or more things
in life. It could simply be due to poverty or an illness of a relative or
oneself, or due to an important event coming up.
Anxious people are:
unable to sleep properly
may have palpitations (conscious of her heart beats)
hands may tremble.
The pulse may be higher than ninety per minute.
What to do in people with anxiety?
Talking to the person and assuring her of support from you and other people around her
is very helpful.
Ensuring that she gets a noiseless place to sleep also is important.
For a week or so, you may help her sleep by asking her to take
CHLORPHENIRAMINE.
If the person is unable to sleep well for more than a week despite your help,
refer her to a doctor.
13. 22-13
2. Depression
Depression means that a person is unusually sad. Although many peo-
ple may feel sad due to the passing away of a person or by failure, they
get back to work very fast and can be made to get interested in day to
day work.
What are the signs of depression?
People who do not get back to work, are unable to mix around, keep to them-
selves and do not cook or take bath when left to themselves are said to be having
Depression. They may oversleep and show no interest in getting out of bed. unusual sadness
Very often they are seen to keep crying and weeping for long periods. is depression
Such a patient also needs to be talked to. Make friends with her and gradu-
ally try to talk more and more with her. Try to make her speak out her fears
and her problems. Without speaking much or commenting whether what
she thinks is right or wrong, try to understand her feelings and then try to
engage her in some small work that may interest her.
However, if the person talks about her desire to die using words like ‘ I
wish I were dead’ or ‘I should have died along with so and so’ it is im-
portant to refer the person to a doctor. Until then inform a person close
to her to keep a watch on her and take care of her as such people may
actually commit suicide. Doctors can give medicines that may help pa-
Suicidal thoughts tients with Depression to see more positively and get over the suicidal
tendency.
3. Psychosis
Usually a person who is seen as ‘mad’ is actually suffering from Psychosis.
A person is said to have psychosis if he / she behaves abnormally :
o like undressing in public o talking on topics without any reference
o talking to no one in particular o very fearful or suspicious of someone without reason
o claims to see and hear things that others cannot.
Abnormal behaviour are signs of psychosis.
Refer to a doctor!
bizarre behaviour
seeing & hearing things talking to self (like undressing in
when there are none public)
Why psychosis happens? What to do in Psychosis ?
Psychosis may be temporary due to medicines or Refer all such patients to a doctor
drugs or even due to an illness. These people are who has specialised in mental ill-
likely to get better when the illness or the effect of nesses – a psychiatrist. However,
the drug wears off. However, those who have such if the person has a tendency to be
behaviour since long will take a long time to im- violent or hurt some one else,
prove but require regular medicines and counsel- send enough people with her to take care of
ling by someone trained for such a thing. her and others who can be at risk.
14. 22-14
Know the Answers
Eye Diseases
a. Please fill in the blanks:
1. Meningitis is due to an infection of the covering of the ___________.
2. Signs of meningitis are ________________, _________________, ______________ and
_______________________.
3. To avoid meningitis among family members of a patient, we can _____________,
________________, and _____________________.
4. Brain stroeks may happen because of __________________ or _______________ of the
blood tubes going to the brains.
5. If you find _________________________________________________ on shining a torch in
the eye of a patient with head injury OR if the big toe goes _____________ when the sole of
the foot is stroked, you must URGENTLY refer the patient to the hospital.
b. Please mark if “right” or “wrong”:
1. People with mental illnesses are mad.
2. People with a fall from a tree may have liver injury
because of which they cannot move their legs.
3. If the pupil of the eye becomes small in both eyes
when you shine a torch in a person with head injury,
it is important to rush to the hospital.
4. Brain strokes due to a clot in the blood supply may cause early death.
5. BCG given to children can avoid TB of the meninges (covering of brain).
