One of the trickiest parts of AP Psychology is memorizing parts of the brain. Yet, these concepts show up repeatedly in the course.
If the anatomy and physiology of the nervous system have you all jumbled up, look no further! I'm a professional tutor who has helped dozens of students master this part of the exam. Below, you'll find everything you need for AP Psychology, without any extras. Plus, I've included all my best tips to help you memorize each part.
Eight Things You Need to Know About the Nervous System
The central nervous system is the brain and the spinal cord.
The peripheral nervous system is the rest of the nervous system.
The peripheral nervous system has two parts. They are the somatic and autonomic nervous systems.
The somatic nervous system transmits messages between the muscles, brain, and sensory organs.
The autonomic nervous system controls many involuntary processes.
The sympathetic nervous system turns on your stress response.
The parasympathetic nervous system turns off your stress response.
The central nervous system is the brain and the spinal cord.
The nerves in the brain and the spinal cord are part of your central nervous system. Your brain and spinal cord are in the center of your body. That makes it easier to remember. It is common to abbreviate central nervous system as "CNS."
The brain processes information from the senses and responds to that information. It also carries out mental processes like thought and emotion. This is a very superficial description of what the brain does. The entire rest of the course will unpack the workings of the brain in detail, so you'll have to forgive me.
The spinal cord transmits messages between the brain and the rest of the body. It is also the site of reflex arcs.
The peripheral nervous system is the rest of the nervous system.
The peripheral nervous system is every nerve in your body that is NOT in your brain or your spinal cord. It is common to abbreviate peripheral nervous system as "PNS."
To remember this, consider the peripherals on a computer. This includes your mouse, printer, or a keyboard. These devices feed information into the computer. They are also used to show information stored on the computer. But they aren't the computer itself. This relationship is like the relationship between central and peripheral nervous system.
Some of my students also think about their peripheral vision. It's on the very outside of the area where they can see. It's not the main event, but rather located out on the sides.
The peripheral nervous system has two parts. They are the somatic and autonomic nervous systems.
The somatic nervous system transmits messages between the muscles, brain, and sensory organs.
The somatic nervous system transmits messages between the muscles, brain, and sensory organs.
The somatic nervous has two primary responsibilities. It transmits messages that coordinate movements that we are aware of and control. It also sends messages between sensory organs and the central nervous system. Sensory organs are parts of the body that can detect thing happening outside of the body. This includes your eyes, ears, and skin. The somatic nervous system coordinates the flow of information between the central nervous system and the body.
Central to these processes are two types of neurons. Neurons send messages from one part of the body to the other. Motor neurons carry information from the central nervous system to the body's muscles. These neurons are vital to our ability to move in a coordinated, controlled fashion. Sensory neurons carry information from the body's organs to the central nervous system. For example, later in this course you will learn about the visual nerve. This nerve carries information from the eye to the brain.
An example from baseball can help us understand how they work together. Let's say it's the bottom of the ninth. Bases loaded. Two strikes, three balls. The pitcher throws a fastball. The batter's eyes will pick up the location of the ball. This information speeds off to his brain. The brain then determines the speed and direction of the ball. It predicts where the ball will be when it crosses the plate. The brain sends directions to the muscles via the spinal cord and the motor neurons. With a little luck, the batter will hit the ball. When the ball hits the bat, the batter's ears, eyes, and hands pick up sensory information. This all goes back to the brain through the spinal cord and the sensory neurons. The brain puts this information together and determines that the bat hit the ball. Then it sends directions to run towards first base via the spinal cord and the motor neurons. The most incredible part is that thousands of cells need only seconds to pull this off!
Note: The new AP Psychology cut afferent and efferent neurons! Rejoice!
The autonomic nervous system controls many involuntary processes.
Autonomic nervous system makes up the other half of the peripheral nervous system. This part of the nervous system regulates involuntary processes. I always remember that autonomic sounds like automatic. The autonomic nervous system causes automatic changes. These changes can include how many times your heart beats or you take a breath during a minute. The autonomic nervous system regulates your blood sugar levels and digestion rate. It even plays a role in how large the pupil of your eye is.
The autonomic nervous system helps regulate our response to stressful events. Heart rate, breathing rate, digestion, and so on all change as a result of stress. It is worth noting that responding to stressful events is a complex process. It involves other parts of the body. This includes the endocrine system. This part of your body regulates your hormones. Parts of the central nervous system can also cause involuntary reactions to stressors. One example of this is a reflex arc, which occurs in the spinal cord. Still, the autonomic nervous system is a critical part of how we respond to stress.
The autonomic nervous system has two parts that help regulate stress. They are the sympathetic and parasympathetic nervous systems.
The sympathetic nervous system turns on your stress response.
The sympathetic nervous system activates your stress response. Careful here! The word "sympathetic" can be misleading. Students often think of someone who listens to you and calms you down when you're upset. But your sympathetic nervous system amps you up. I remember that sympathetic starts with an "s." Stress also starts with an s. The sympathetic nervous system starts the stress.
When you experience a stressful event, it can cause things to change in your body. Other parts of the course cover stress management and individual experiences of stress. For right now, lets focus on the body. Your body has to prepare to take action when faced with a stressors. The faster this happens, the faster you can respond. In some situations, seconds can make a big difference.
The sympathetic nervous system sends signals that change your body's automatic processes. This causes your heart rate increases, as does your breath rate. You will stop digesting food to conserve energy. Your body releases sugars into your blood stream in seconds. You may feel nervous, jittery energy before a big exam or game. You may not want to eat or feel like your heart is pounding in your chest. As long as this isn't causing extreme distress or interfering with your life, this is normal. Stressful events and anxiety are a normal part of life.
The body does these things to prepare a rapid response to a stressful event. There are several responses to stress.
Fight. This can be a physical response, like attacking someone or defending yourself. It also includes aggressive responses. A dog bearing it's teeth or a cat growling is a signal of this type of response.
Flight. This is escaping or avoiding a stressful experience.
Freeze. This is not moving. Small animals like rabbits and birds respond to predators this way. A freeze response makes a creature less visible to the threat.
Flop. This is falling over. Possums and women in classic movies use the flop response.
Note that they all start with "f." This is handy for memorization!
The parasympathetic nervous system turns off the stress response.
The parasympathetic nervous system reigns in our sympathetic nervous system. It's job is to turn off our stress response. The parasympathetic nervous system slows down our heart and breath rate. It also restarts digestion and stops the flow of excess energy into the body. For this reason, we sometimes call this the "rest and digest" response.
The parasympathetic nervous system plays a vital role in human health. The stress response uses up a lot of energy. It also causes physical damage to our bodies, and it's distressing. Let's unpack each of those things. It takes a tremendous amount of energy to run the body's processes in overdrive. Reduced digestion and increased need for energy depletes your body's energy reserves. This can make it difficult to respond to a real threat that occurs later. Our parasympathetic nervous systems slows us down and restarts digestion. This counteracts these negative effects.
Stress damages the body's systems and processes. Usually, this damage is minimal. Resting and eating helps our bodies redirect resources to repair tissues. When people experience prolonged stress, small damages can add up to significant consequences. For example, frequent stress is a risk factor for heart attacks and a weakened immune system. Finally, stress strains people's emotional and psychological well-being. Stress increases an individual's risk of depression, anxiety, and post-traumatic stress disorders.
Note that the stress response itself is not bad. It's adaptive and helpful when something stressful happens. If a possum flops over and doesn't get eaten, that's a win for the possum. Mild stress can be motivating. For example, worrying about a due date can help people overcome procrastination. But a life of constant stress is harmful. The parasympathetic nervous system protects us from these negative effects. It turns off the stress response when it doesn't serve us anymore.
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