The nervous system

• The nervous system informs the body about itself and the world to allow the body to react to this info it communicates with electrical and chemical signals
• The central nervous system (CNS) is a division of the nervous sytem containing the brain and spinal cord. It analyses info arriving from the PNS and initiates appropriate responses to be sent to muscles and organs via the PNS. Its roles are decision making and coordination. Complex decisions happen in the brain and simple decisions e.g. reflexes happen in the spinal cord. Most info travelling to and from the brain does so via the spinal cord.
• The peripheral nervous system (PNS) is a division of the nervous system and transmits info from the environment to the CNS and from the CNS to the rest of the body. Its made up of all other nerves apart from the brain and spinal cord.
• The somatic nervous system (SNS) is a division of the PNS it consists of sensory nerves which carry sensory info from the environment to the CNS and the motor nerves which carry instructions from the CNS to the skeleton muscles to that appropriate movements can occur it therefore carries commands from the motor cortex. Involves voluntary movements so they are aware and choose to do it.
• The automatic nervous system (ANS) is a division from the PNS it monitors and controls vital activities to sustain life processes e.g. heartrate and glands e.g. sexual arousal. Its involved in involuntary actions. The control ce3nters for the ANS are the brain stem and hypothalamus. It is the system which controls activities such as sweating and breathing - don't have conscious control. There are 2 divisions of the ANS that act together to ensure the body reacts appropriately to situations.
• The sympathetic branch (SANS) is a division of the ANS has connections from the spinal cord to the major internal organs. It helps prepare the body for activity e.g. threat. It prepares the body to mobilise energy resources due to the secretion of the NT noradrenalin which results in increased heartrate and breathing and oxygen - inhibits digestion. Controls the fight / flight response prepares for action in danger increases adrenalin and makes the mouth dry.
• The parasympathetic branch (PANS) its a division of the ANS consists of connections from the brain and internal organs. Its a chill out response and ensures we conserve our energy it becomes less active when the SANS is active. it prepares the storage of energy resources due to the secretion of the NT acetylcholine. Can make them tired, decreases breathing and heartrate increases saliva and makes you thirsty. When the threat is gone everything decreases - rest and digest response.