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Brain and Nervous System Cheat Sheet
A printable reference covering neuron structure, action potentials, neurotransmitters, brain regions, and nervous system divisions for grades 9-12.
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This cheat sheet covers the major parts of the brain and nervous system that explain how people sense, think, feel, and act. Students need these ideas to understand how biological processes connect to behavior in psychology. It is useful for reviewing brain structures, neuron signaling, and the organization of the central and peripheral nervous systems. The goal is to make key terms and pathways easy to compare at a glance. The nervous system is divided into the central nervous system, which includes the brain and spinal cord, and the peripheral nervous system, which connects the body to the central nervous system. Neurons communicate through electrical signals called action potentials and chemical messages called neurotransmitters. Major brain areas include the brainstem, cerebellum, limbic system, and cerebral cortex. Important formulas and rules include resting potential about -70 mV, action potential threshold about -55 mV, and the all-or-none principle.
Key Facts
- The central nervous system, or CNS, consists of the brain and spinal cord.
- The peripheral nervous system, or PNS, includes all nerves outside the brain and spinal cord.
- A typical neuron receives signals through dendrites, sends signals down the axon, and releases neurotransmitters from axon terminals.
- Resting potential is about -70 mV, meaning the inside of a neuron is more negative than the outside when it is not firing.
- An action potential usually begins when the neuron reaches a threshold of about -55 mV.
- The all-or-none principle means a neuron either fires a full action potential or does not fire at all.
- The sympathetic nervous system prepares the body for action, while the parasympathetic nervous system calms the body after stress.
- The frontal lobe supports planning, decision-making, movement, and impulse control.
Vocabulary
- Neuron
- A specialized nerve cell that receives, processes, and sends information through electrical and chemical signals.
- Synapse
- The tiny gap between neurons where neurotransmitters carry messages from one cell to another.
- Neurotransmitter
- A chemical messenger released by a neuron that affects the activity of another neuron, muscle, or gland.
- Action Potential
- A brief electrical impulse that travels down an axon when a neuron reaches threshold.
- Limbic System
- A group of brain structures involved in emotion, memory, motivation, and basic drives.
- Cerebral Cortex
- The wrinkled outer layer of the brain that supports higher mental functions such as thinking, language, perception, and voluntary movement.
Common Mistakes to Avoid
- Confusing the central nervous system with the peripheral nervous system is wrong because the CNS includes only the brain and spinal cord, while the PNS includes nerves outside them.
- Thinking stronger stimuli create bigger action potentials is wrong because action potentials follow the all-or-none principle and do not vary in size.
- Saying neurotransmitters travel down the axon is wrong because the electrical action potential travels down the axon, while neurotransmitters cross the synapse.
- Assuming the left and right brain hemispheres work completely separately is wrong because most tasks use networks across both hemispheres.
- Labeling the sympathetic system as calming is wrong because the sympathetic system increases arousal, while the parasympathetic system supports rest and recovery.
Practice Questions
- 1 A neuron has a resting potential of -70 mV and reaches threshold at -55 mV. How many millivolts must the membrane potential change to reach threshold?
- 2 If a signal travels along a 1.5 meter nerve pathway at 50 meters per second, how long does the signal take to travel the pathway?
- 3 Name the nervous system division most active when heart rate rises, breathing speeds up, and the body prepares for danger.
- 4 Explain why damage to the frontal lobe can affect both movement and decision-making.