The Nervous System
This part of the nervous system includes the brain and spinal cord.
Central Nervous System
This neurotransmitter is linked to pleasure, movement, and attention. Too much is linked to schizophrenia, too little to Parkinson’s.
Dopamine
This hormone is responsible for the "fight-or-flight" response.
Adrenaline
This hormone helps regulate sleep and wake cycles, especially in response to darkness.
Melatonin
This is the tiny gap between neurons where neurotransmitters are released.
Synapse
This system connects the brain and spinal cord to the rest of the body.
Peripheral Nervous System
This neurotransmitter affects mood, sleep, and appetite; low levels of it are commonly linked to depression.
Serotonin
This hormone tells the brain when you are hungry.
Ghrelin
This chemical is involved in pain transmission and helps send "ouch!" signals to the brain.
Substance P
This is the process where extra neurotransmitters are reabsorbed by the sending neuron.
Reuptake
This division of the peripheral nervous system controls voluntary muscle movements.
Somatic Nervous System
This neurotransmitter is the brain’s main excitatory chemical and plays a major role in learning and memory.
This hormone, sometimes called the “love hormone,” is involved in bonding, childbirth, and trust.
Oxytocin
This condition is caused by damage to the myelin sheath, slowing down neural impulses.
Multiple Sclerosis
The brief time after an action potential when a neuron can’t fire again.
Refractory Period
This system controls automatic body functions like heartbeat and digestion.
Autonomic Nervous System
This neurotransmitter blocks pain signals and is released during exercise, excitement, or injury—it's the brain’s natural painkiller.
Endorphins
This hormone tells the brain when you are full so you will stop eating.
Leptin
This neurotransmitter helps control alertness and arousal and is heavily involved in the body’s fight-or-flight response.
Norepinephrine
This principle means that a neuron either fires at full strength or not at all.
All-or-Nothing Principle
These two branches of the autonomic nervous system work like opposites—one prepares the body for action, and the other calms it down.
Sympathetic and Parasympathetic Nervous Systems
This neurotransmitter calms the brain and helps reduce anxiety; it's the main inhibitory neurotransmitter.
GABA
This neurotransmitter blocks pain signals and is released during exercise, excitement, or injury—it's the brain’s natural painkiller.
Endorphins
These two types of neurotransmitters either increase or decrease the chance that the next neuron will fire.
Excitatory and Inhibitory neurotransmitters
This is the neuron’s charge when it’s not firing, typically about -70mV.
Resting Potential
This neurotransmitter is essential for muscle movement and is also linked to memory; low levels are associated with Alzheimer's disease.
Acetylcholine