Among all body systems, the central nervous system occupies a special place. The brain regulates all the functions that a person is endowed with. Thanks to him, the relationship between the work of organs and systems is carried out. Without brain regulation, man would not be a viable being. Thanks to the coordinated activity of the central nervous system, we move, speak, think and feel external stimuli. The brain has a complex structure, each of its components is responsible for a certain function. Nevertheless, all its structures provide the work of our body only in aggregate. Particularly important formations that make up the central nervous system are the medulla oblongata and the pons. They contain the main vital centers (vascular, respiratory, cough, tear separation), and also give rise to most cranial nerves.
Brain structure
The structural unit of the central nervous system is a neuron. This cell is responsible for the reception, processing and storage of information. The whole human brain is a cluster of neurons and their processes - axons and dendrites. They provide the transmission of signals entering the central nervous system and back to the organs. The brain consists of gray and white matter. The first is formed by the neurons themselves, the second is their axons. The main structures of the brain are the hemisphere (left and right), cerebellum and trunk. The former are responsible for the mental abilities of a person, his memory, thinking, imagination. The cerebellum is necessary for coordination of movements, in particular, it provides the ability to stand upright, walk, take objects. Under it is the Varoliev bridge. It is the link between the medulla oblongata and the cerebellum.
Varoliev bridge: structure and functions
The bridge is one part of the hindbrain. Its length ranges from 2.4 to 2.6 cm. The Varoliev bridge has a mass of about 7 g. The structures that border it are an elongated and midbrain, a transverse groove. The main components of the parsley bridge are the upper and middle legs of the cerebellum, which are large conduction pathways. In front is the basilar sulcus, which contains arteries that feed the brain, and the trigeminal exit site is located nearby . On the back side of the Varolian bridge forms the upper part of the rhomboid fossa, in which 6 and part 7 of the cranial nerves are embedded. In the upper part of the bridge lies the largest number of nuclei (5, 6, 7, 8). At the base of the bridge there are conducting descending paths: corticospinal, bulbar and bridge tracts.
The main functions of this body:
- Conduction - along its paths nerve impulses pass to the cerebral cortex and to the spinal cord.
- Sensory function - is provided thanks to the vestibulo-cochlear and trigeminal nerves. In the nuclei of the 8th pair of cranial nerves, information on vestibular stimuli is processed.
- Motor - provides the reduction of all facial muscles. This is due to the trigeminal nuclei. In addition, its sensitive part receives information from the receptors of the oral mucosa, eyeball, part of the head and teeth. These signals are sent along the fibers of the bridge to the cerebral cortex.
- Integrative function provides the relationship between the forebrain and hindbrain.
- Brain reflexes.
Reticular bridge formation
The reticular formation is a branched network located in the brain and consisting of nerve cells and nuclei. It is present in almost all formations of the central nervous system and smoothly passes from one department to another. The reticular formation of the Varolian bridge is located between the medulla oblongata and the midbrain. Its long processes - axons, form a white matter and pass into the cerebellum. In addition, along the fibers of the nerve cells of the bridge, signals can be transferred from the head to the back. In addition, the reticular formation transmits signals to the cerebral cortex, due to which a person awakens or sleeps. The nuclei located in this part of the bridge belong to the center of respiration located in the medulla oblongata.
Bridge reflex function
The ability of the central nervous system to respond to external stimuli is called a reflex. An example is the appearance of salivation at the sight of food, the desire to sleep with the sound of soothing music, etc. Reflexes of the brain can be conditional and unconditional. The first person acquires in the process of life, they can be developed or adjusted depending on our desire. The latter are unconscious, they are laid with birth, and it is impossible to change them. These include chewing, swallowing, grabbing and other reflexes.
How a bridge affects reflexes
Due to the fact that the Varoliev bridge is an integral part of the quadruple, it is related to the development of auditory and statistical reflexes. Thanks to the latter, we are able to hold the body in a certain position. In addition, interacting with the midbrain, it closes a significant part of muscle reflexes.