Alright buddy, kalIn this we will discuss about Central Nervous System (Brain and Spinal Cord). The human central nervous system consists of the brain and spinal cord [baca : Sistem Saraf Manusia]. The brain has a protector in the form of the skull, while the spinal cord is protected by the vertebrae. In addition to the protection in the form of bones, these two organs are also protected by meninges.
The meninges consist of three layers, from inside to outside:
1. Pia Mater
Pia master (pia = soft) is the membrane closest to the surface of the brain and spinal cord. This layer inserts itself into the gaps in the brain and spinal cord. This layer contains many blood vessels, so it plays a role in distributing oxygen and nutrients and removing metabolic waste.
2. Arachnoid
The arachnoid is a soft web, located between the pia mater and dura mater.
3. Dura Mater
The dura mater (dura = tough / hard) is the outermost layer that is dense and hard and united with the skull.

Meningeal Layer

Between the arachnoid layer and the pia mater is a cavity known as the subarachnoid cavity, Yat contains cerebrospinal fluid. Cerebrospinal fluid serves as a cushion for the brain to protect the brain from impact on the skull. This cerebrospinal fluid also functions to carry nutrients, hormones, and white blood cells to parts of the brain for nourishment. Cerebrospinal fluid is alkaline (alkaline) and clear (like plasma). This liquid is produced from choroid plexus located in the ventricles. The ventricles are cavities in the brain. The choroid plexus is a fold of the pia mater which is rich in blood vessels. So, the ventricles also contain cerebrospinal fluid.

Supporting Article: Definition and Functions of Hormones in Humans 

Anatomy of the ventricles of the brain that drain cerebrospinal fluid

The brain and spinal cord have the main substances, namely:
  1. gray matter (grissea substance), is gray in color and is a collection of cell bodies.
  2. white substance (white matter), is white and is a collection of nerve fibers.

Nerve fibers are covered by fat which serves to protect, nourish, and separate the nerve fibers [baca : Pengertian dan Jenis Sel Saraf (Neuron)]. The presence of this barrier results in a white color in the white matter.
The brain and spinal cord have both substances, but in a different arrangement. In the brain, the gray matter is located in the cortex (skin) and the white substance is located in the middle. In the spinal cord is the opposite of the brain, ie the gray substance is located in the middle (inside), in cross section it is shaped like a butterfly, while the white substance is located in the cortex.
Differences in the position of the gray and white matter between the spinal cord and the brain

The brain is the main nerve center located within the cranial cavity. The size of the human brain varies, determined by a person’s gender, age, and physical size. The size of the human brain reaches its maximum at the age of 18 years. The adult brain weighs about 1.4 kg. The human brain consists of two hemispheres (hemisphere) the big one. Because there are nerves that cross the spinal pathway [baca : Perjalanan Impuls Saraf], then the left hemisphere controls the right side of the body and the right brain controls the left side of the body.
The brain is divided into 3 regions, namely the forebrain, midbrain, and hindbrain. The division of this area is evident only during brain development in the embryonic phase, while in the adult human brain it is not obvious because each consists of several parts or lobes.
a. Forebrain or Big Brain
The most prominent part of the human brain is the cerebrum, which is located in the forebrain. The cerebrum consists of two hemispheres, namely the left and right hemispheres. Each hemisphere regulates and serves the opposite body part, ie the left hemisphere governs the right body part and vice versa. Therefore, if the left side of the brain is disturbed or abnormal, then the right side of the body will be disturbed, and vice versa. Each hemisphere of the cerebrum mentioned above is divided into four lobes, namely frontal, parietal, occipital, and temporal. Between the frontal and parietal buses are separated by the central sulcus (middle cleft) or Rolando gap.
The forebrain is composed of two layers, namely:
  1. Outer layer (cortex), which is a thin layer of gray. This layer contains the nerve cell bodies. The surface of the cortex layer is folded, so that the surface becomes wider. In the cortex layer there are various kinds of nerve centers.
  2. Inner layer, which is the white layer. The inner layer contains many nerve fibers, namely dendrites and neurites[baca : Pengertian dan Jenis Sel Saraf (Neuron)].

The forebrain is the main nerve center, because it has an important function in regulating all body activities, especially those related to intelligence (intelligence), memory (memory), awareness, and consideration. Specifically, these activities are controlled in different areas.

Cerebrum anatomy

Areas in the forebrain that are very important are also the hypothalamus and thalamus. The hypothalamus is a small area located at the base of the forebrain and weighs a few milligrams. The hypothalamus acts as the center for regulating body homeostasis, for example, it is related to regulating body temperature, thirst, hunger and satiety, urine output, regulating hormone secretion from the anterior and posterior pituitary glands. [baca : Perbedaan Hormon Hipofisis Anterior dan Posterior], and reproductive behavior.
Location of the thalamus and hypothalamus

The thalamus, located above the hypothalamus, acts as arelay station” for sensory information sent to the cerebrum. Thus, the thalamus will select and channel important sensory impulses to the cerebrum.
b. Middle Brain
midbrain (Diencephalon) humans are quite small and inconspicuous, located in front of the cerebellum and the Varol bridge (ons Varolii). The largest part of the midbrain in most Vertebrates is the optic lobe which varies in size. In mammals (including humans) there are corporate quadrigemina(as the optic lobe in lower vertebrates) which functions to help coordinate eye movements, eye pupil size (widen/narrow), and certain auditory reflexes. In addition, the midbrain contains Yat centers that control balance and nerve fibers that connect the forebrain and hindbrain, as well as between the forebrain and the eyes. The midbrain is the upper part of the brainstem. All bundles of nerve fibers that carry sensory information before entering the thalamus pass through the midbrain.
c. Back Brain
The hindbrain includes the Varol bridge (pons Varolii), advanced marrow (medulla oblongata), and the cerebellum (cerebellum). These three parts make up the brain stem.
1. Varol Bridge (pons Varolii)
The Varol bridge contains nerve fibers that connect the left and right lobes of the cerebellum, and connects the cerebellum to the cortex of the cerebrum.
2. Advanced marrow (medulla oblongata)
The advanced marrow or medulla oblongata forms the lower part of the brainstem and connects the pons Varolii with the spinal cord.spinal cord). The advanced marrow acts as a respiratory control center by transmitting nerve impulses that stimulate the muscles between the ribs and the diaphragm. In addition, it also acts as a center for regulating physiological reflexes, such as heart rate, blood pressure, body temperature, dilation or constriction of blood vessels, movement of the digestive organs, and secretions of the digestive glands. Another function is to regulate reflexes, such as coughing, blinking, and sneezing [baca : PerbedaanGerak Sadar dan Gerak Refleks].
3. Cerebellum (cerebellum)
The cerebellum (cerebellum) is the largest part of the hindbrain. This cerebellum is located under the occipital lobe of the cerebrum. The cerebellum consists of two hemispheres and the surface is curved. The function of the cerebellum is to regulate posture or body position, balance, and coordination of muscle movements that occur consciously.
brain stem part

The spinal cord is located in the cavity of the vertebrae, extending from the cervical vertebrae to between the first and second lumbar vertebrae. The arrangement of the spinal cord is the same as that of the advanced marrow (medulla oblongata), which is composed of two layers: the outer layer is white containing dendrites and neurites, while the inner layer is gray which contains many nerve cells.[baca : Sistem Saraf Tepi (Saraf Kranial dan SarafOtonom)].

The gray cross section of the inner spinal cord is shaped like a butterfly (some say it looks like the letter H) and consists of:
  1. Dorsal root containing sensory nerves
  2. The ventral root contains the referent motor nerve
  3. Central canal (central canal), which is a channel containing cerebrospinal fluid associated with the ventricular cavity in the brain

The white substance that surrounds and surrounds the gray substance contains:
  1. Spinal nerve fibers coming from the gray matter
  2. Nerve fibers along the spinal cord that connect the spinal nerves to the brain.

The function of the spinal cord is as a center for reflexes, conducts sensory impulses from the skin or from muscles to the brain, and carries motor impulses from the brain to the muscles of the body.

This is a post about Central Nervous System (Brain and Spinal Cord), hopefully it can be useful for all friends. Thank you very much J