nervous system

• The nervous system is the main system that controls the mind and the body. It is a network of nerve cells that transmit information (via neurons) between different parts of the body, allowing communication to take place. It coordinates a wide range of conscious functions such as thinking and movement as well as unconscious functions such as the control of organs.
• The central nervous system is the main control system for life functions and conscious psychological processes. It’s responsibilities include receiving, processing and responding to sensory information
• The brain is an organ of nervous tissue that is responsible for responses, sensation, movement, emotions, communication, thought processing, and memory.
• The brain is responsible for:

  • Perception (i.e. translating information from the senses so it can be understood and processed)
  • Motor control (i.e. sending commands to muscles to move)
  • Regulating bodily processes and maintaining homeostasis (e.g. maintaining temperature and hormone levels based on information from the peripheral nervous system)
  • Sleep
• The brain provides conscious awareness and is involved in all psychological processes. The brain consists of many regions, which are responsible for different functions.
• The brain consists of four main lobes:

  • frontal lobe
  • parietal lobe
  • temporal lobe
  • occipital lobe
• The occipital lobe processes visual information. It helps determine distance, depth, colour, and other aspects of vision. The occipital lobe is a part of your brain located at the back of your head.
• The parietal lobe integrates information from the different senses and therefore plays an important role in spatial navigation. It processes your sense of touch and assembles input from your other senses into a form you can use. The brain's parietal lobe is located immediately behind the frontal lobe
• The frontal lobe is associated with higher cognitive functions, including memory, emotions, impulse control, problem solving, social interaction, and motor function. The frontal lobe is located in the forward part of the brain,
• The brain stem connects the brain and spinal cord and controls involuntary processes, including our heartbeat, breathing and consciousness.
• The spinal cord connects the brain with the peripheral nervous system and the rest of the body and with the external world.
• The spinal cord is also responsible for some unconscious movements, such as reflexes (e.g. the one where you get hit on the knee and your leg kicks).
• The role of the peripheral nervous system (PNS) is to relay messages (nerve impulses) from the central nervous system (CNS [brain and spinal cord]) to the rest of the body. The PNS consists of two main components: 1) the somatic nervous system and 2) the autonomic nervous system.
• The somatic nervous system (SNS) is a component of the peripheral nervous system responsible for voluntary movement and the reception of external stimuli. It regulates activities under conscious control, such as skeletal muscle contraction.
• The SNS comprises motor neurons that activate muscles and sensory neurons that relay information (sight, touch, taste etc) from sensory receptors to the central nervous system (CNS).
• The autonomic nervous system (ANS) is responsible for transmitting information between the central nervous system and the internal organs (i.e. it connects the brain to the rest of the body). Unlike the somatic nervous system, it is involuntary and not under conscious control. These automatic behaviours include breathing and heart rate
• the sympathetic nervous, increases heart rate, decreases stomach acid and digestion, dilates pupils and dilates bronchioles
• the parasympathetic nervous, decreases heart rate, increases stomach acid and digestion, constricts pupils and constricts bronchioles
• The autonomic nervous system (ANS) is responsible for transmitting information between the central nervous system and the internal organs (i.e. it connects the brain to the rest of the body). Unlike the somatic nervous system, it is involuntary and not under conscious control. These automatic behaviours include breathing and heart rate
• synaptic transmission is the process of sending information from one neuron to another
• neurons are separated by small gaps called synapses / synaptic cleft
• information is passed down the axon of the neuron as an electrical impulse known as action potential.
• when the electrical signal within a neuron reaches the axon terminal of that neuron, neurotransmitters are released from vesicles and cross over the synapse where they are taken up by receptors in the dendrites of the other neuron
• whilst signals within neurons are transmitted electrically, signals between neurons are transmitted chemically (neurotransmitters are chemicals)
• when a neurotransmitter is taken up by the receptor of the next neuron, it is converted back to an electrical signals which passes along the axon of that neuron until it reaches the axon terminal, where the chain can continue
• neurons contain may different types of neurotransmitters such as serotonin, dopamine, glutamate, GABA and acetylcholine
• these different neurotransmitters can have either excitatory or inhibitory effects on the postsynaptic neuron
• excitatory → increases the likelihood of the neuron firing
• for example, serotonin has a generally inhibitory effect. when it binds to the receptor of a neuron , it increases the negative charge of that neuron, making it less like the fire
• in contrast, glutamate has an excitatory effect. so if glutamate outweighs serotonin in a neuron, the net effect is increased likelihood of that neuron firing
• Neurons are cells that are specialised to carry neural information electrically and chemically throughout the body (communication). 
• Neurons can be one of three types: sensory neurons, relay neurons and motor neurons. Neurons typically consist of a cell body, dendrites and an axon.
• the cell body contains the nucleus and mitochondria; providing energy to the neuron
• the node of ranvier are the gaps in the myelin sheath
• the axon terminal passes information onto other neurons
• the schwann cells are cells that produce myelin
• the myelin sheath is a fatty substance that insulates the axon
• the axon takes information away from the cell body and towards the axon terminals
• the nucleus contains the chromosomes (genetics)
• dendrites receive messages from other neurons in order to trigger an action potential