Function of spinal cord

Learning Objectives By the end of this section, you will be able to: • Identify the anatomical and functional divisions of the nervous system • Relate the functional and structural differences between gray matter and white matter structures of the nervous system to the structure of neurons • List the basic functions of the nervous system The picture you have in your mind of the nervous system probably includes the brain, the nervous tissue contained within the cranium, and the spinal cord, the extension of nervous tissue within the vertebral column. That suggests it is made of two organs—and you may not even think of the spinal cord as an organ—but the nervous system is a very complex structure. Within the brain, many different and separate regions are responsible for many different and separate functions. It is as if the nervous system is composed of many organs that all look similar and can only be differentiated using tools such as the microscope or electrophysiology. In comparison, it is easy to see that the stomach is different than the esophagus or the liver, so you can imagine the digestive system as a collection of specific organs. The Central and Peripheral Nervous Systems The nervous system can be divided into two major regions: the central and peripheral nervous systems. The central nervous system (CNS) is the brain and spinal cord, and the peripheral nervous system (PNS) is everything else ( Figure 12.2 Central and Peripheral Nervous System The structures o...

Your peripheral nervous system (PNS) is one of two main parts of your body’s nervous system. Your PNS feeds information into your brain from most of your senses. It carries signals that allow you to move your muscles. Your PNS also delivers signals that your brain uses to control vital, unconscious processes like your heartbeat and breathing. Overview The central and peripheral nervous systems. The peripheral nervous system branches outward from the spinal cord and brain to reach every part of your body. What is the peripheral nervous system? Your peripheral nervous system (PNS) is that part of your nervous system that lies outside your Some of those signals, like the ones to your heart and gut, are automatic. Others, like the ones that control movement, are under your control. What’s the difference between the peripheral and central nervous systems? Your Your peripheral nervous system is everything else and includes nerves that travel from your spinal cord and brain to supply your face and the rest of your body. The term “peripheral” is from the Greek word that means around or outside the center. Function What does the peripheral nervous system do? Your peripheral nervous system has two main subsystems: autonomic and somatic. • Autonomic: These are nervous system processes your brain runs automatically and without you thinking about them. • Somatic: These are functions you manage by thinking about them. Those two subsystems are how your peripheral nervous system does its ...

Spinal nerves are the major nerves of the body. There are a total of 31 symmetrical pairs of spinal nerves that emerge from different segments of the spine. Each spinal nerve contains both sensory and motor nerve fibers. These relay motor (movement), sensory (sensation), and autonomic (involuntary functions) signals between the spinal cord and other parts of the body. The spinal cord is composed of nerve cells that serve to relay messages between the brain and the peripheral nerves. The spinal nerves receive sensory messages from tiny nerves located in areas such as the skin, internal organs, and bones. The spinal nerves send sensory messages to the sensory roots, then to sensory fibers in the posterior (back or dorsal) part of the spinal cord. • Eight cervical spinal nerves on each side of the spine called C1 through C8 • Twelve thoracic spinal nerves in each side of the body called T1 through T12 • Five lumbar spinal nerves on each side called L1 through L5 • Five sacral spinal nerves in each side called S1 through S5 • One coccygeal nerve on each side called Co1 • • Brachial plexus: Formed by the merging of spinal nerves C5 through T1, this plexus branches into nerves that carry sensory messages and provide motor control to the muscles of the arm and upper back. • Lumbar plexus: Spinal nerves L1 through L4 converge to form the lumbar plexus. This plexus splits into nerves that carry sensory messages and provide motor control to the muscles of the abdomen and leg. • Sacr...

The We depend on the spinal column to be the main support of our body. It allows us to stand upright, bend, and twist while protecting the spinal cord from injury. If the spinal cord is injured, it often causes issues like: • Permanent changes in the body’s strength; • Loss of sensation; and • Loss of motor control or other functions. Because the spinal cord is central to the body’s functions, a person’s life can be drastically changed when an The Major Functions of the Spinal Cord The spinal cord’s • Electrochemical communication. Electrical currents travel up and down the spinal cord and across nerves, sending signals which allow different segments of the body to communicate with the brain. • Walking. While a person walks, a collection of muscle groups in the legs are constantly contracting and relaxing. The action of taking step after step may seem incredibly simple to us since we have been doing it all of our lives, but there are actually a lot of factors that have to be coordinated properly to allow this to happen. This central pattern generators in the spinal cord are made up of neurons which send signals to the muscles in the legs, making them relax or contract, and produce the alternating movements which occur when a person walks. • Reflexes. Reflexes are involuntary responses resulting from stimuli involving the brain, spinal cord, and nerves of the peripheral nervous system. The Structure of the Spinal Cord The overall structure of the spinal cord is enclosed by ...