The human brain coordinates and regulates all body functions important for normal life, and also controls behavior. Desires, thoughts, feelings - everything is connected with the work of the brain. If this organ does not function, the person becomes a "plant".
The human brain: characteristics
The brain is a symmetrical structure, however, like many other organs. The weight of the brain at birth is about three hundred grams, in adulthood it already weighs one and a half kilograms. Considering the structure of the human brain, you can immediately detect two hemispheres, which hide deep formations underneath. The hemispheres are covered with peculiar convolutions that increase the outer medulla. Behind - the cerebellum, below - the trunk, passing into the spinal cord. Nerve endings branch off both from the trunk and from the spinal cord itself, it is through them that information from the receptors flows to the brain, it is through them that the human brain sends signals to the glands and muscles.
Inside the brain there is white matter, which is nerve fibers that connect various parts of the organ with each other and form nerves that extend to other organs, and gray matter that forms the cortexbrain and consisting mainly of bodies of nerve cells. The human brain is protected by a skull - a bone case. The substances inside the organ and the bone walls are separated by three shells: hard (outer), soft (inner) and thin arachnoid. The resulting space between the shells is filled in composition with cerebrospinal (cerebrospinal) fluid similar to blood plasma. The fluid itself is produced in the ventricles of the brain - the cavities inside it, its role is to supply the human brain with the necessary nutrients.
Carotid arteries provide cerebral blood supply, they are divided at the base into large branches that go to different parts of the brain. Surprisingly, 20 percent of all blood circulating in the body continuously flows to the brain, although the weight of the organ itself of the total human weight is only 2.5 percent. Together with the blood, oxygen enters the brain, supplying it is extremely important, since the body's own energy reserves are quite small.
Brain cells
Cells called neurons make up the central nervous system. They are responsible for processing information. The human brain includes from 5 to 20 billion neurons. In addition to them, there are glial cells in the organ, which are approximately 10 times more than neurons. Glial cells form the framework of nerve tissues and fill the space between neurons. Like any other cell, neurons are surrounded by a plasma membrane. Processes depart from the cells - axons (most often one cell has one axon with a length ofa couple of centimeters to several meters) and dendrites (each neuron has many dendrites, they are branching and short).
The human brain: divisions
Conventionally, the brain is divided into three sections: the anterior brain, trunk, cerebellum. The forebrain consists of two hemispheres, the thalamus (the sensory nucleus that receives information from the organs and transmits it to the sensory cortex) and the hypothalamus (the area that controls homeostatic functions), the pituitary gland is an important gland. The hemispheres are the largest parts of the brain, interconnected by the corpus callosum - a bundle of axons. Each hemisphere has occipital, parietal, temporal and frontal lobes. The trunk includes the medulla oblongata (the lower part of the trunk that passes into the spinal cord), the pons varolii (connected to the cerebellum by nerve fibers) and the midbrain (motor pathways go through it to the spinal cord). The cerebellum is located under the occipital lobes of the cerebral hemispheres, it controls the position of the trunk, limbs, head, plays an important role in the development of motor skills.
