Your Brain

Amygdala: Amygdala is Located just above the hypothalamus gland of the brain, the amygdala is an almond shaped, one inch long, situated deep within the temporal lobes of the brain. We have two amygdalae, each one situated a few inches away from either ear. This tiny mass has been associated with a person's mental and emotional state. This name amygdala comes from the Greek word for almond and has been named so because its size and shape bears semblance to that of an almond. This amygdala features presence of several nerves that connect it to various centres of the brain such as the neocortex and visual cortex and forms a part of the limbic system which is an important part of the nervous system. Let's understand the different amygdala functions in our body.

ANS: The Autonomic Nervous System it is a part of the nervous system which controls the digestion, heart and other autonomic functions.

A cool thing about the nervous system is that can pass messages at 300 km/hour! And another cool fact is that if you are un-conscious it is because you have de-prived the brain of blood for more than 10 seconds.

.: Science of the Brain :.

The brain is a member of the nervous system family. The nervous system controls all your conscious and automatic actions and sensations in all parts of your body like your thoughts, feelings, memories, heartbeat, blood pressure, body temperature, breathing rate and senses.

There are two parts of the nervous system - central and peripheral. The central nervous system is composed of the brain and the spinal cord. The branching web of nerves to all the different parts of your body is the peripheral system. The nervous system is controlled by the brain and is connected to the spinal cord and the huge network of nerves that run from the spinal cord to all the different parts of the body. Your nerves are like electrical a wire which picks up signals. Signals or messages flows from these nerves to the spinal cord, then to the brain and back again. These signals are called nerve impulses. The brain is the control centre.  It receives and sorts out millions of signals it receives from all   the different parts of your body. The brain sorts out information with amazing speed. Incredibly, it also sorts out important information and ordinary information. For example, it tells you not to pay attention to a bird singing so you can drop the hot skewer you just picked up. The nervous system also controls your breathing, heartbeat, body temperature, and the actions of your stomach and intestines.

As you look at your computer screen, electrical signals or nerve impulses are sent to your brain so you can do many different actions. Your nervous system is telling your finger to move the mouse, move your eye muscles so you can focus on the words, recognize words and sentences, form new ideas and store what you just learned in your brain and makes you remember.

The Human Brain

Your brain is wrapped by layers of lining called the meninges. The topmost layer is called the dura mater. Sandwiched between the brain and the meninges is brain fluid called the cerebrospinal fluid? This brain fluid acts as a shock absorber. For extra protection, the brain's house is a strong bony box called skull. Like your skin, the germs can attack the meninges. If this happens the person gets very sick and this condition is called meningitis.

The brain is greyish pink in colour, feels like tofu and would you believe only weighs three pounds, approximately the weight of a new born baby 1.3 kilos. It makes up only 2% of your body size but uses up 20% of the energy your body produces. Energy is from blood sugar or glucose.  Arteries which run to all parts of your brain carry the blood that delivers the food and oxygen to your brain.

There are three main parts of the brain:

Cerebrum, Cerebellum and Brain Stem.

Cerebrum

The cerebrum is the largest part of the brain. It looks like a wrinkled giant walnut. The cerebrum is divided into two halves. Each half is called a hemisphere. The left side is the left hemisphere and the right side is the right hemisphere. The halves or hemispheres are connected to each other by a wide material called the corpus callosum. Each hemisphere has an inside layer called the white matter and an outside layer of gray matter called the cerebral cortex. Different parts of the cortex do different jobs.  The cortex controls your voluntary actions like running and walking. It is also responsonsible for body sensations like pain, learning, and emotions. These areas can be found on the top of the cerebrum. If your brain is injured and your speech centre is damaged, you may not be able to talk clearly.  If your motor area is damaged, you may not be able to walk as well as you did before or you can be paralysed.

It is weird but the right side of your brain is connected to the left side of your body. The left side of the brain is connected to the right side of your body. This is because the nerves connecting the brain and the spinal cord cross to the opposite side. If you are right handed, you depend on your left hemisphere or left brain. So, you are probably good at solving problems, math, and language.  If you are a left hander, you are probably good in music, drawing and singing.

If you turn the brain upside down, there are twelve pairs of nerves called cranial nerves that come out from the brain itself. These nerves have names and also do very important jobs. For example, the olfactory nerve is the nerve for smell, and the optic nerve is the nerve for vision.

Cerebellum

The cerebellum is the second largest part of your brain. It is below the cerebrum and sort of looks like a ball of yarn. Its main job is to coordinate your movements, posture and keeping your balance. Damage or injury to the part of this brain will make your movements jerky and uncoordinated.

Brain Stem

The brains stem is on the top of the spinal cord. The brain stem deals with very important functions that keep us alive. It automatically controls our breathing, heartbeat, blood pressure, and circulation. If this does not happen automatically, can you imagine what would happen if you forget to breathe? LoL!!!

Thalamus

The thalamus is responsible for sending sensory messages to the cerebrum.

Hypothalamus

The hypothalamus is located at the base of the brain. It controls many body functions like body temperature, appetite, thirst, and sleeping. It also regulates a gland in our body called the pituitary gland.  The pituitary gland is the master of all the other glands in our body because it helps the other glands to produce their hormones. It also produces growth hormone which makes us grow tall and helps the kidneys regulate the water we drink.

The Spinal Cord

Your spinal cord is a long tube that begins from the bottom of the brain and runs down to your lower back. There are nerves called the spinal nerves that come out of the spinal cord. It looks like a tree branch with twigs hanging from the sides. These nerves carry electrical signals or messages up and down the spinal cord to your brain where the messages are sorted out. The spinal cord connects the brain to the rest of the body. Just like the brain, the spinal cord is also wrapped by the meninges for protection. It is inside a tunnel of bones stacked up on its other called the vertebrae or backbones.

You’re Nerves

If you look at the brain under the microscope, you see a mess of bundles of nerve cells which looks like long knotted pieces of wool or your room like mine. These bundles of nerves are your electrical cables. There are 100 billion of these nerve cells called neurons. They also have an important job to do. These neurons carry and send the electrical signals from the peripheral nerves to the brain and back again. They can send a message from your arm to your head in 5 microseconds.

The neuron is composed of a cell body, dendrites and the axon. The cell body looks like a blob and has an eye called the nucleus. Coming out of the cell body are fingers called the dendrites and a long leg?  A single nerve cell can have 50,000 dendrite branches and can communicate with 250,000 other nerve cells.

The long leg connected to the cell body is the axon and looks like a string of sausages. The axon can be over three feet long. The axon carries nerve impulses from the cell body to the dendrite of the next neuron.   The neurons do not really connect to each other.  When the messages reach the feet of the axon which are called the axon terminals, the nerve impulse has to cross a gap so it can reach the dendrite of the next cell.  As the messages or nerve impulses arrive at the gap, a chemical called neurotransmitter is released.  This chemical acts like a bridge so the message is passed to the next neuron. So the nerve impulses are like playing a game of relay. Some nerves are covered by a lining called myelin sheath. The sheath around the axon insulates the axon to speed up the passage of nerve impulses. Top speed in covered nerves can reach 120.3 metres per second!

When you are born, you already have your whole package of neurons with you.  The bad news is that the human brain cannot make new neurons.  When they get damaged they die, period. The good news is that every time you learn something new, new nerve connections are made. So the funny thing is the more tangled your brain, the smarter you are!

The nerves names are:

supra-clavicular (on your shoulder)

vagus (on your neck)

inter-costal (below your ribs)

median (above your wrist)

ulnar (where your wrist is)

femoral (on the front of your thigh)

sciatic (on the back of your thigh)

peroneal (where your knee is now how doctors check your reflex whith a rubber hammer)

tibial (where your calf is)

 Main  parts of the brain and what it does

Cerebrum: The brain's thinking area.

Cerebellum: The brains movement control area.

Spinal cord: Nerve message motorway to & from the brain.

Three systems CNS, PNS, ANS. Central nervous system (CNS), Peripheral Nervous System (PNS), Autonomic Nervous System (ANS).

In the Nervous System There is 31 spinal pairs and 12 cranial pairs.

Interesting facts about the brain

• The brain can live 4-6 seconds without oxygen
• The energy from the brain is enough to light up a light bulb (25 watts)
• Then brain produces 70'000 thoughts on a average day
  
89.06 is the percentage of people that use their right hand, 10.6% with their left and 0.34% with either hand.
• Albert Einsteins brain weighed 1.230 grams less than average of a normal human brain which is 1,300-1,400