Understanding the Function and Structure of Animal Nervous Systems

Almost all animals have a nervous system. Neurons bundle together to form nerves. The purpose of the nervous system is to coordinate all activities of the body, and enables the body to respond and adapt to changes both inside and outside. The central nervous and the peripheral nervous systems are very similar but different at the same time. The CNS is made up of the brain and spinal cord and functions mainly to process information and determine the appropriate responses. The central nervous system receives sensory information, figures out a response, and initiates a motor response if appropriate. The CNS is protected by the skull, vertebral column, and a membrane. The spinal cord provides communication between the brain and the peripheral nerves

The parasympathetic nervous system does the opposite and brings the body back to normal. Sensory neurons are unipolar in shape and there are two types based on where the sensory neurons originate. Somatic sensory neurons are located in the skin skeletal muscles and joints bringing information to the CNS. It is made up of nerves that connect to skin, sensory organs, and skeletal muscles. One sensory neuron, photoreceptors in the eye, sense light. The neural impulses are then transmitted down the axons of the sensory neurons to the brain, where the brain then interprets what that input means. PNS plays a role in regulating blood pressure, thirst, and body temperature. Thermoreceptors in the skin help the body sense temperature. Motor neurons are completely different than sensory neurons, because they receive a signal from the central nervous system and tell responsive tissues what to do. Though most often associated with controlling muscle movement they also signal the glandular tissues and control secretion of various substances like gastric juices and saliva. Visceral sensory neurons give information to the CNS but not on a conscious level. Some internal organs that need regulating, but not at a conscious level are gallbladder, liver, kidney, and