The brain is the main regulator of all functional functions of the body, as well as its behavioral acts, which are aimed at adapting to external conditions of life.
The medulla oblongata is an extension of the spinal cord. It has a gray substance located outside and a white substance located inside. Accumulations of cell bodies of neurons form nuclei in the medulla oblongata. The medulla oblongata is a vital organ. With its defeat, a violation of reflex somatic and autonomic acts occurs, and when it is destroyed, death occurs. The medulla oblongata performs conduction and reflex functions. The brain regulates the following reflexes: cardiac activity, vascular tone, respiration, coughing, sneezing, salivation, swallowing, gastric and pancreatic secretions, vomiting, metabolism, lacrimation, blinking and closing of the eyelids, skeletal muscle tonic reflexes.
The activity of the centers of the medulla oblongata is associated with the manifestation of posture reflexes. Reflexes of the posture are called such reflexes that cause a redistribution of muscle tone of the limbs with a change in the position of the head.
The brain and cerebellum are connected by afferent and efferent fibers to all parts of the central nervous system, and through them to the muscles and many receptors of the body, as well as to the autonomic nervous system.
The main functions of the cerebellum include: 1) regulation of motor acts; 2) regulation of vegetative processes. These functions of the cerebellum were established in experiments using methods of extirpation, irritation, registration of cerebellar biocurrents, and clinical observations.
The cerebellum is well developed in birds and is of great importance for their highly developed sense of balance. In the first period after removal of the cerebellum, the bird cannot fly and walk. When trying to move, cramps appear, and the bird falls on its side. However, she can take food and drink. After some time, the condition improves and the bird is able, although with difficulty, to stand, walk and fly. Scientific studies have found that in the cerebellum there are centers that regulate the activity of the autonomic nervous system.
The brain of the birds (midbrain) is well developed and consists of two parts: the doppler and the legs. The bicollis has anterior and posterior lobes and is formed by the nuclei of sensitive neurons.
The main functions of the midbrain: 1. The front part of the dicollis is the primary visual center. Here is the primary analysis of light stimulation. With the help of these centers, an approximate reaction to light stimulation (turning the head toward a light stimulus) is carried out. The centers of the anterior part of the doppler regulate the narrowing of the pupil. 2. The back of the dvuhmoly carries out an indicative reaction to sound stimuli (turning the head toward a sound stimulus). 3. The black substance is involved in the regulation of skeletal muscle contractions. It also regulates the act of swallowing and the rhythm of breathing. 4. The brain, or rather the midbrain, has centers of positioning rectifier reflexes. Rectifying reflexes are called reflexes that restore the normal position of the body after its violation.
The brain of reptiles, unlike the brain of birds, has poorly developed cerebral hemispheres.
The diencephalon consists of the thalamus, epithalamus and hypothalamus. The diencephalon performs a variety of functions. 1. The thalamus is a collector that collects impulses from all receptors in the body (visual, auditory, taste, tactile, temperature, pain, proprioreceptors) and directs them to the cerebral hemispheres. 2. In the nuclei of the thalamus, afferent impulses undergo initial analysis and synthesis. 3. In the thalamus, afferent impulses acquire an emotional coloring. There is a feeling of pain, a feeling of pleasant and unpleasant. 4. The thalamus regulates the plastic muscle tone, due to which birds can take and maintain various poses. 5. In the epithalamus are centers that regulate the activity of the olfactory analyzer. 6. In the hypothalamus are localized centers that regulate the expansion of the pupil, blood pressure, respiration, motor and secretory functions of the digestive tract. 7. The hypothalamus regulates body temperature.