the somatic nervous system consists of 12 pairs of

NERVOUS SYSTEM

The nervous system is the human's information center and control system. The fundamental social unit in the organization is the nerve cell, called nerve cell. A neuron consists of a cell body, one major branching fiber (axone), and numerous smaller branching fibers (dendrites). Each neuron is affiliated to other neurons by synapses on the axons and dendrites. A neuron receives chemical signals from strange neurons through the synapses. All of these incoming signals are combined as an electrical signal within the nerve cell, and IT may operating theatre may not send an outgoing chemical signal out its axon to other set of synapses. The nervous system can be divided into central anxious system (CNS) and peripheral nervous system (PNS).

The CNS processes information, initiates responses, and integrates mental processes. The central excited system consists of the brain and the medulla spinalis. The mastermind is burglarproof away the skull, and the medulla spinalis is protected past the vertebrae. Three connective tissue layers (the meninges) surround and protect the brain and spinal cord. They are dura mater (outermost), arachnoid (mediate), and Tacca leontopetaloides mater (innermost). In improver, a liquid called cerebrospinal fluid, between the arachnoid and Tacca pinnatifida mater, protects the brain and spinal cord from injury.

The systema nervosum periphericum (PNS) consists of os part, consisting of 12 pairs of nerves, and spinal part, consisting of 31 pairs of nervousness. The PNS collects information from numerous sources both within and on the surface of the individual and relays it away way of afferent fibers to the central neural system. Efferent fibers in the PNS electrical relay data from the CNS to various parts of the body, principally to muscles and glands. Peripheral nerves run from the spinal cord to every parts of the body. The parts of this system are named for the four spinal regions from which they limb: neck (cervical), chest (thoracic), lower back out (lumbar), and pelvis (sacral). The medulla spinalis acts as a central communication network to transmit signals back and forth between the brain and peripheral nervous system of rules. 2 subdivisions comprise the PNS: the afferent nerve, or sensory, division and the efferent, or motor, division. Afferent neurons carry natural process potentials from the periphery to the Central nervous system, and efferent neurons carry action potentials from the CNS to the periphery. The efferent neurons belong to either the somatomotor (somatic) nervous system, which supplies skeletal muscles, or to the involuntary flighty system (ANS), which supplies shine muscles, cardiac muscleman, and glands. The ANS regulates the activities of viscera such as the heart, profligate vessels, digestive organs and generative organs. This arrangement controls distribution of blood flow, regularisation of blood pressure, heartbeat, sweating, and blood heat.

Various forms of nerve cells.

A. Pyramidal cell. B. Small multipolar cell, in which the axon quickly divides into numerous branches. C. Undersize fusiform cell. D and E. Ganglion cells (E shows T-formed division of axon).

ax. Axon. c. Capsule.

the somatic nervous system consists of 12 pairs of

Source: https://helpiks.org/5-20696.html

Berbagi :