nervous system

• def - body wide system of nerve cells that collect info and take acttion by directing bodily organs and muscles via the transmission of electro chemical messages
• split into two parts - central and peripheral
• central - complex processing - brain and spinal cord
• pns - sensory neurones - collects sensory info - sensory neurones to the cns and motor neurones away from cns
• somatic nervers system - skeletal muscles - voluntary - conscious control
• autonomic nervous system - actions of internal organs - involuntary sytem not under conscious control
• autonomic - sympathetic and parasympathetic
• sympathetic - increased bodily activities
• para-sympathetic - decreases bodily activities
• homeostasis - the regulation of internal enviornemnt
• reflex arc - sensation detected by sensory neurone - electrical signal from dendrite to axon turns into chemical signal - onto relay neuron then to motor neurone
• synaptic transmission - point where two neurones almost touch
• synaptic transmission - action potential arrives at axon terminal - causes vesticles to merge to the mebrane of presynaptic cell - releases neurotransmitters to synaptic cleft - diffuses - reaches psot synpatic then summation
• summation - for new electrical action to form needs to pass threshold - there are a range of neurotransmitters - some are exhitatory which make the charge more positive
• positive - depolaraise
• negative - hyperpolarise
• unidirectional - can onyl travel one way
• dopamine - neurotransmitter that helps with movement, attention, learning
• neuroadrenaline - associated with fight or flight
• sensory neurone

  
• relay neurone

  
• motor neurone
• sam pathway - coping with acute stress
• sam - sympathetic branch of autonomic nervous system
• same - hypothalamus activates sympathetic nervous system which triggers adrenal medulla - releases adrenaline and noradrenaline which leads to the fight or flight response