A. UNDERSTANDING DEFINITION OF THE BRAIN
The brain is an organ that functions as the central
nervous system in humans and most other living creatures. It means, the brain
is means the brain is the control center of our body, the brain regulates most
of the coordination, movement, behavior, balance in the body, and various other
functions. The human brain volume is about 1350 cc and consists of
approximately 100 million nerve cells, weighing about 2.5 percent of body
weight. The brain is located in the cavity of the skull and is protected by a
membrane called the meninges membrane.
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| THE BRAIN |
B. FUNCTION OF THE BRAIN
As the most important organ in the human body, the
brain has many functions, the following are some of the main functions of the
brain:
- Central nervous system that regulates the entire body, it makes a person able to translate the information and all the stimuli perceived by the body, for Example pain, touch, pressure, etc.
- Center of the ability to think, speak and hear that someone could capture the verbal information and then translate it, and can receive visual information from the light and see objects in accordance with the actual shapes of that objects.
- Center of balance and motoric skills (movement) so that one is able to move as he wishes.
- The Center of conscious activity
- Maintaining the stability of the body when we awake or when we sleep
- Control Center of the entire organ system in the body, such as the respiratory system, circulatory system, digestive system, hormonal system, reproductive and other systems in the body.
C. STRUCTURE OF THE BRAIN
The human brain consists of two cells, the nerve
cells (neurons) and glial cells (neuroglia). Nerve cells are cells that are
sensitive to stimuli and are capable of delivering that stimulus. Based on its
function, human nerve cells divided into three kinds of cells ; the sensory
nerve, motor nerve cells, and nerve cells (connecting nerve cells). Whereas
glial cells (neuroglia) is a cell that serves to support and assist nerve
cells. Neuroglia serves to provide and support nutrition, maintain homeostasis
(balance of fluid and electrolyte), forming the myelin sheath (a part of nerve
cells) and participate in signal transmission of the nervous system.
C. PROTECTIVE COATING OF THE BRAIN (THE
MENINGES)
Meninges membrane is a protective tissue of the brain
that separates the brain from the skull. The meninges composed of collagen and
elastic fibrils network and there is a clear fluid called cerebrospinal fluid.
Meninges membrane consists of three layers, namely:
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| THE MENINGES |
1. dura mater
Dura mater an outer membrane that is thick and
strong. This structure contains collagen fibers elastic, fibrosit, nerves,
blood vessels and lymph vessels. Dura mater has a function to protect the brain
because it is strong and somewhat flexible.
2. Arachnoid
Mater
Arachnoid mater membrane is a layer consisting of flat
fibrosit and collagen fibers. Arachnoid has two parts, the part that relates to
the dura meter, and the part that relates to the pia mater. Arachnoid is a
transparent structure which have waterproof cell, serves as a cushion to the
central nervous system.
3. Pia mater
Pia mater is the closest membrane to the brain. Pia
mater is a thin, smooth and soft membrane. Pia mater shape is following the
outer structure of the brain. Pia mater composed by fibrosit cells, a few
collagen fibers and blood vessels that penetrate the brain. Pia mater can also
function as a supplier of nutrients for nerve tissue.
D. PART OF THE BRAIN
1. Cerebrum
Cerebrum is the largest and most prominent part of
the brain. Cerebrum consists of two hemispheres, the right hemisphere and the
left brain. Each hemisphere of the brain regulate most of the performance of the
opposite body, meaning that the right brain governing the performance of the
left body, as well as the left brain that regulates most of the right body's
performance. Cerebrum responsible for many things, we will explain the function
of Cerebrum by each major part of the brain.
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| PARTS OF THE BRAIN |
Cerebrum has four lobes, which are:
a. Frontal
lobe
The frontal lobe of the brain is a part of which is
located at the front. The frontal lobe function is to regulate motor activity
(movement) consciously, speech, thinking (problem solving) and emotions.
b. Parietal
lobe
The parietal lobe is located behind the frontal lobe
at the top of the cerebrum. The main function of the parietal lobe is as a
sensory center (admission stimulation), for example, a touch of pressure,
temperature, pain, etc.
c. Temporal
lobe
Temporal lobe is the part of the brain that is
located under the parietal lobe. The main function of the temporal lobe is as
center of the auditory and language system.
d. Occipital
lobe
The occipital lobe is at the back of cerebrum. The
main function of the occipital lobe is as the center of vision (visual).
Based on the structure, Cerebrum is divided into two
part :
(1) The
cerebrum cortex (outer part)
The cortex is a thin gray layer that have billions of
nerve cell bodies. The cortex is also called as the gray matter area. These
nerve cells are interconnected to one another and form as a chains so that the
information received by the nerve cell can be forwarded through communication
with other nerve cells. The cortex is subdivided into three main areas, namely:
- Sensory area, which is the area in charge interpret sensory information (stimuli), for example, light, taste and sound.
- Motor area, an area that should control the muscles, so that we can move, such as when a person stepped on thorns, there will be a reflex by moving away the foot from the thorn.
- Association area, an area that serves to record the experience of the body (memory), will, intelligence, and set some language functions.
(2) Basal
Ganglia (Inside)
The basal ganglia is a white area that contains
dendrites and axons of the nerve cells. This layer is thicker than the cortex.
The basal ganglia function is in coordinating movement, regulating involuntary
movements, cognitive and emotion.
2. Small brain
(cerebellum)
The cerebellum is the part of the brain located below
the occipital lobe of the cerebrum The cerebellum is the part that is made up
of two hemispheres with a folds seperiti shaped surface. Cerebellum main
function is to control the movement and muscle coordination consciously, as well
as the body's center of balance. Several recent studies have also shown that
the cerebellum play a part in determining the emotional and cognitive
information (mental). The cerebellum has three lobes, Anterior Lobe, Posterior
Lobe and Flocculonodular Lobe.
3. Brainstem
The brain stem is the part of the brain located in
the front of the cerebellum and below the cerebrum. At the time of controlling
voluntary movement, the Brainstem is the part that must be passed impulse to
reach Cerebrum. The brain stem can also be said to be the part that connects
the brain to the spinal cord. Actually, the brainstem is the term for a
combination of three important structures below:
a. Midbrain
Midbrain known as the smallest part of the brain. The
midbrain has a primary function as a station impulse of vision, hearing, eye
movements and body movements. In the midbrain there is an important part called
the substantia nigra, this part is dark in color and can produce dopamine for
the movement of the body.
b. medulla
oblongata
The medulla oblongata is the part that controls
autonomic functions throughout the body. Some of the medulla function is to regulate
heartbeat, breathing, swallowing, digestion, and sneezing. Most of these
processes are regulated by the medulla oblongata relate to one another.
c. Pons
Pons is a part of the brain stem that is located
under the midbrain and above the medulla oblongata. Its size is about 2.5 cm,
its main function is as an intermediary to transfer the signal path between a Cerebrum
and Cerebellum, sending signals cranial nerves (nerves that relate directly to
the brain) to the outside of the brain, face and ears, as well as contribute to
the control autonomic functions (unconscious).
4. The limbic
system (Limbic System)
The limbic system is the part of the brain that has
three main functions ; emotions, memories, and passion. The system is composed
by several parts:
- Thalamus, a part that is responsible for receiving and delivering information from the human sensory system.
- The hypothalamus, a part which serves to produce several hormones. This hormone will be in charge of controlling the fluid balance, sleeps cycles, body temperature and food intake.
- The amygdala, a collection of bean-shaped neural tissue that function to emotions, survival instinct and memory.
- Hippocampus, the part that functions is to recall a memory and space navigation.
