brain and neuropsychology

• The divisions of the human nervous system include the central nervous system (CNS) which coordinates incoming information and makes decisions about movement or other activities, and the peripheral nervous system (PNS) which collects information from, and sends information to, different parts of the human body.
• The central nervous system consists of the brain and the spinal cord.
• The peripheral nervous system consists of the somatic nervous system (SNS) which is a network of nerve fibres running throughout the body, and sense receptors such as those in our skin, muscles and internal organs, and the autonomic nervous system (ANS) which is a network of special nerves that take information to and from the CNS but do so more slowly as the nerve fibres are not myelinated.
• The autonomic nervous system (ANS) uses information from our internal organs to coordinate our general physiological functioning and also responds directly to information such as stressful or emotional events.
• The autonomic nervous system (ANS) is split into two divisions: the sympathetic and parasympathetic divisions.
• The sympathetic division sets off arousal, which can be mild like a feeling of anxiety, or extreme such as the fight or flight response.
• The sympathetic division is activated when an individual feels “under threat”.
• The parasympathetic division allows the body to store up energy when we are not “under threat”.
• The autonomic nervous system (ANS) is the part of the nervous system which helps us react quickly and strongly to emergency situations.
• The autonomic nervous system (ANS) is responsible for breathing, digestion and is the main link between the brain and the endocrine system which is a set of glands that release hormones into the blood stream.
• Hormones change the state of the body and when adrenaline is released, it activates the heart, making it beat faster ready for action.
• The release of adrenaline is part of the fight or flight response.
• The fight or flight response allows you to call on energy and strength to deal with the situation regardless of whether you choose to run away or stay and fight.
• The autonomic nervous system (ANS) steps in when a threat is detected and sends messages to your body, making it ready for action which is what we know as the fight or flight response.
• The autonomic nervous system switches from parasympathetic activity to sympathetic activity during the fight or flight response.
• The result of the fight or flight response is we breath more deeply, our heart rate increases and the blood carries more oxygen.
• Our eyes also dilate and we also begin to sweat more to cool our muscles.
• The digestive system also changes so we metabolise sugar quickly, enabling instant energy.
• The blood also thickens in preparation for possible injury so it clots more easily.
• The brain also produces natural painkillers known as endorphins.
• This state is maintained by the endocrine system, which continues to release adrenaline to keep the body in the aroused state.
• The parasympathetic division is in control of the body under normal conditions, storing energy.
• If a threat is detected, the sympathetic division activates and the body begins to prepare for action with the fight or flight response.
• Once the threat as gone, the ANS switches back to having the parasympathetic division in control.
• William James was one of the first to investigate the fight or flight reaction and how the body reacted to stressful events by increased heart rate, deep breathing and sweating.
• James described how you save yourself from falling by grabbing the banister and how this reaction happened very quickly.
• Following this, your heart speeds up, you breath deeply and you begin to sweat.
• James believed that emotions were simply us perceiving physical changes in the body which the brain interprets and concludes which emotions are being felt.
• James described this in his own words as: “We do not weep because we feel sorry: we feel sorry because we weep”.
• Not all researchers have not been convinced that the James-Lange theory is an accurate explanation of how we experience emotional arousal.
• Schachter and Singer suggested it is not only physiological changes that occur when we perceive a threatening situation, but there was also a cognitive component.
• The argument is that when we experience stimulation in the ANS, we also interpret the situation we are in.
• Research evidence shows physiological change and cognitive interpretations both lead to emotional experiences.
• The James-Lange theory did promote a great deal of research and recognised the importance of the ANS in emotional experiences.
• Neurons are special cells in the brain that exchange chemicals to generate small electrical impulses, enabling information to be passed around.
• There are three types of neurons in the nervous system: Sensory Neurons, Relay Neurons, and Motor Neurons.
• Sensory neurons carry information from the sense organs to the central nervous system (CNS).
• Relay neurons relay information within the CNS.
• Motor neurons send information from the CNS to the muscles.
• Sensory neurons have a cell body, with two stems on either side.