The nervous system

• The primary internal communication system in our body is responsible for collecting and responding to information in the environment as well as co-ordinating the working of cells and organs in the body
• The internal communication system has two subsystems with different functions, the central nervous system (CNS) and the peripheral nervous system (PNS)
• The CNS, comprising of the brain and spinal cord, is responsible for controlling behaviour and regulating the body’s physiological processes
• The brain must be able to receive information from the sensory receptors and be able to send messages to the muscles and glands of the body
• The brain can be divided into four main areas-the cerebrum, cerebellum, diencephalon and brain stem
• The cerebrum is the largest part of the brain and its further divided into four main different lobes, each of which has a different primary function
• The cerebrum is split down the middle into two halves called cerebral hemisphere, each hemispheres is specialised for particular behaviours and the two halves communicate with each other through the corpus callosum
• The diencephalon lies beneath the cerebrum and on top of the brain stem. Within this area are two important structures, the thalamus and the hypothalamus
• The thalamus acts as a relay station for nerve impulses coming from the senses, routing them to the appropriate part of the brain where they can be processed
• The main function of the spinal cord are to relay information between the brain and the rest of the body which allows the brain to monitor and regulate bodily processes, like digestion and breathing, and to coordinate voluntary movements
• The function of the peripheral nervous system is to relay nerve impulses from the CNS to the rest of the body and from the body back to the CNS
• The somatic system is made up of 12 pairs of cranial nerves and 31 pairs of spinal nerves. These nerves have both sensory neurons and motor neurons
• The autonomic nervous system has two branches that tend to have the opposite effects on organs, the sympathetic and parasympathetic nervous systems
• Then you type on a keyboard or take a drink you’re performing voluntary actions and are conscious of what you’re doing. However, the body also carries out some actions without your conscious awareness, which are regulated by the ANS
• The sympathetic system is primarily involved in response that help us to deal with emergencies like increasing heart rate and blood pressure and dilating blood vessels in the muscles
• If we think of the SNS as pushing an individual into action when faced with an emergency, then the parasympathetic nervous system (PNS) relaxes them again once the emergency has passed