parasympathetic and sympathetic
31.3 Peripheral nervous system The peripheral nervous system is broken down into two sub-systems, the somatic nervous system and the autonomic nervous system. ANS - Autonomic Nervous System The ANS has two components - parasympathetic and sympathetic. The sympathetic nervous system is the "fight or flight" or fright response and results in an increased heart rate, increased rate of breathing, and an elevated blood glucose level. There is also decreased digestion. The second neurotransmitter is epinephrine. In this case, the first neuron is short and the second neuron is long. The parasympathetic nervous system is the rest and digest system. Drugs must be able to pass the blood brain barrier to have an effect on the CNS. Drugs act by affecting the neuron and how likely it is to fire an action potential. Stroke occurs when there is a blood clot that goes to the brain and prevent blood flow.