Synapse: Is a junction where a axon interacts with another neuron Presynaptic Terminal: End of the axon Postsynaptic Membrane: Membrane of the dendrite Synaptic Cleft: Space between the presynaptic membrane and postsynaptic membrane Synaptic vesicles: Stores chemical neurotransmitters

Excitatory - increase membrane permeability, increases chance for threshold to be achieved to trigger an action potential Inhibitory - decrease membrane permeability, decrease chance for threshold to be achieved to trigger an action potential

Acetylcholine ACh - stimulates muscle contraction Norepinephrine & Dopamine (sense of feeling good, low levels = probable cause to depression) Serotonin (sleepiness) Endorphins (reduce pain, inhibit receptors)

Reflex: An involuntary reaction in response to a stimulus Reflex Arch: Pathway in which a reflex occurs.

Sensory Nerves - conduct impulses into the brain or spinal cord Motor Nerves - carry impulses to muscles of glands from the brain and spinal cord Mixed Nerves - contain both sensory and motor nerves

5 steps of Reflex Arch 1. Sensory Receptor 2. Afferent neuron 3. interneuron 4. Motor neuron 5. Effector organ

Reflex arc - only includes a few neurons Reflex Behavior – automatic and subconscious responses Stretch or Knee-jerk reflex – Muscles contract when applied force it put on them (patellar reflex) Withdrawal reflex - avoidance of painful stimuli

Converging Pathways: More than one neuron synapses converge on the same neuron. (more than one neuronal pathway) Diverging Pathways: The axon from one neuron divides or diverges with one or more neurons. (one neuronal pathways can diverge into multiple pathways)