The nervous system

• The central nervous system, also known as CNS, is composed of the brain and spinal cord.
• The right hemisphere of the brain controls the left side of our body.
• The left hemisphere controls the right side of our body.
• The brain is the centre of all our conscious awareness and where all decision making takes place.
• The brainstem, located at the bottom of the brain, controls many basic functions such as autonomic activity, regulating sleep and directs some reflex responses.
• The brainstem connects to the spinal cord, which carries incoming and outgoing messages between the brain and the rest of the body.
• The CNS coordinates incoming sensory information.
• Thinking, decision making and language are all part of CNS.
• The Peripheral Nervous System, or PNS, collects information from and sends messages to different parts of the body, acting as a network of nerve fibres connecting various parts of the body with CNS.
• The PNS is subdivided into the Autonomic Nervous System, or ANS, and the Somatic Nervous System, or SNS.
• The Autonomic Nervous System, or ANS, is involuntary and deals with many different emotions we feel.
• The Somatic Nervous System, or SNS, is voluntary and transmits information from the sense organs to CNS.
• The SNS receives information from the CNS that directs muscles to act.
• The SNS allows us to see and move.
• Parasympathetic nervous system: Rest and digest response.
• The body is returned to its normal resting state during the parasympathetic nervous system's Rest and digest response.
• Sympathetic nervous system: Fight or flight response.
• During the sympathetic nervous system's Fight or flight response, breathing gets faster, heart beats rapidly, and the person sweats.
• Psychological arousal: Fight or flight - the way in which an animal responds when stressed.
• The body becomes physiologically aroused in readiness to fight an aggressor or in some cases flee during the fight or flight response.
• Stages of flight or fight: The brain (hypothalamus - CNS) detects threat.
• The sympathetic division of the ANS acts during the stages of flight or fight.
• Adrenaline is released during the stages of flight or fight.
• The changes from a normal resting state (parasympathetic) to a state of psychological arousal (sympathetic) occur during the stages of flight or fight.
• The fight or flight response: Adrenaline is released and the heart beats faster, they help confront the threat or give us energy to run away.
• Rest and digest is triggered once the threat has passed.
• The parasympathetic division returns the body to the resting state during the stages of flight or fight.