Introduction to the Peripheral Nervous System: Study with Video Lessons, Practice Problems & Examples

The peripheral nervous system (PNS) encompasses all neural structures outside the central nervous system (CNS), which includes the brain and spinal cord. It plays a crucial role in sensory perception and motor function, utilizing afferent nerves to send signals to the CNS and efferent nerves to execute commands. Key components include sensory receptors, ganglia, and motor endings. For example, when sensing heat from a flame, the PNS relays this information to the CNS, which then instructs the PNS to react, demonstrating the system's integral role in maintaining homeostasis and responsiveness to stimuli.

Peripheral Nervous System

Hey everyone and welcome to the peripheral nervous system. Now, as you may remember from quite a few videos back, the peripheral nervous system represents all neural structures outside of the CNS. So the CNS is, of course, the brain and spinal cord. And then the peripheral nervous system, the PNS, is pretty much everything else. The PNS has the very important task of making us aware of the world around us and helping us actually navigate it. It's going to be sending all kinds of information up to the central nervous system and then actually carrying out the actions that the CNS wants us to do. The PNS is comprised of several different components. First, we have sensory receptors. It also contains afferent and efferent nerves and their associated ganglia. And you guys remember ganglia from a while back, right? Those are just clusters of neuron cell bodies that exist outside the CNS, so in the PNS. An easy way to kind of remember the difference between afferent and efferent nerves is that afferent nerves facilitate the arrival of a signal to the CNS. So afferent arrival. In other words, this is the PNS sending information up to the central nervous system. And then efferent nerves facilitate the exit of a signal from the CNS. So efferent exit. That is basically the central nervous system sending commands or information down to your peripheral nervous system. And then finally we also have motor endings. We're going to cover all of these, these topics in more detail in upcoming videos so don't worry too much about the nitty-gritty of each of these. For now, just know that these are the components that make up the peripheral nervous system. Alright, scooching down to our figure here we have this cute little person and we can see we have the central nervous system depicted in purple. We have our brain and our spinal cord there, and then all of these little pink nerves make up the peripheral nervous system. We have this little cartoon for you here to showcase how the central and peripheral nervous systems work together and what their relationship is like. So if you can imagine a scenario where you're holding a match and the flame is getting, like, a little too close to your skin, it's getting a little dangerous, what's going to happen is that sensory receptors in your skin are going to sense that heat, and then your peripheral nervous system will send signals up to your CNS using your afferent division. Right? Those signals will arrive in the brain, and your PNS is basically saying, hey. We're sensing too much heat in the hand. This is not going good. And then your central nervous system will make the executive decision, alright. We're gonna move the hand. And then what's gonna happen is those commands will get sent down to the peripheral nervous system through those efferent fibers. They will exit the brain and go down to your PNS and we will actually see movement. We'll drop the match or whatever needs to happen. That's what the relationship between these two systems is like. The CNS is in charge. The PNS is kind of like the little soldier carrying out all of those necessary actions. Alright. So that is the peripheral nervous system in a nutshell, and I will see you guys in our next video to talk about some of these systems in a bit more detail. See you there.

Introduction to the Peripheral Nervous System Example 1

Hey there. So this example is asking us, which of the following does not require the use of the peripheral nervous system? As a reminder, the peripheral nervous system is responsible for sending information to our brain about our internal and external environment, encompassing all that sensory information. It also carries out the motor activities that our brain wants to happen. Looking at these answer choices, I can see (a) raising your hand in class is a motor activity that would engage our PNS. So we want what does not require the PNS. Thus, (a) is out. (b) Thinking about the answer to a problem is cognitive. This activity would just involve your CNS. So (b) is looking promising, but we'll underline it for now. (c) Clicking on the correct answer to a problem is a motor activity. And (d) feeling the warmth from a cup of coffee is a sensation that comes from our PNS. Therefore, our answer is indeed (b). Thinking about the answer to a problem would not require the PNS; that would be a purely CNS-driven activity. Alright. See you guys in our next one. Bye bye.

Which of the following structures can be found in the afferent division of the PNS?

• A. Sensory receptors.
• B. Motor endings.
• C. Motor neurons.
• D. Skeletal muscles.

Here’s what students ask on this topic:

What is the peripheral nervous system and what are its main components?

The peripheral nervous system (PNS) includes all neural structures outside the central nervous system (CNS), which comprises the brain and spinal cord. The PNS is essential for sensory perception and motor function. Its main components are sensory receptors, afferent and efferent nerves, and ganglia. Sensory receptors detect stimuli from the environment, afferent nerves carry signals to the CNS, and efferent nerves transmit commands from the CNS to the body. Ganglia are clusters of neuron cell bodies located outside the CNS. Together, these components enable the PNS to relay information to and from the CNS, facilitating responses to external stimuli.

How do afferent and efferent nerves differ in the peripheral nervous system?

Afferent and efferent nerves serve distinct functions in the peripheral nervous system (PNS). Afferent nerves, also known as sensory nerves, carry signals from sensory receptors to the central nervous system (CNS). They facilitate the arrival of sensory information, such as touch, pain, and temperature, to the brain and spinal cord. In contrast, efferent nerves, or motor nerves, transmit commands from the CNS to the muscles and glands, facilitating the exit of signals. This allows the body to perform actions and responses, such as moving a hand away from a hot object. In summary, afferent nerves bring information to the CNS, while efferent nerves carry out the CNS's commands.

What role do sensory receptors play in the peripheral nervous system?

Sensory receptors are crucial components of the peripheral nervous system (PNS). They detect and respond to various stimuli from the external and internal environments, such as touch, temperature, pain, and pressure. These receptors convert physical or chemical stimuli into electrical signals, which are then transmitted via afferent nerves to the central nervous system (CNS). This process allows the brain and spinal cord to interpret sensory information and make appropriate decisions. For example, when you touch a hot surface, sensory receptors in your skin detect the heat and send signals to the CNS, prompting a quick response to move your hand away.

How does the peripheral nervous system interact with the central nervous system?

The peripheral nervous system (PNS) and central nervous system (CNS) work together to maintain homeostasis and respond to stimuli. The PNS detects sensory information through receptors and sends it to the CNS via afferent nerves. The CNS processes this information and makes decisions. Commands are then sent back to the PNS through efferent nerves to execute actions. For instance, if you touch a hot object, sensory receptors in your skin send signals to the CNS, which processes the information and sends a command via efferent nerves to move your hand away. This interaction ensures coordinated and efficient responses to environmental changes.

What are ganglia and what function do they serve in the peripheral nervous system?

Ganglia are clusters of neuron cell bodies located outside the central nervous system (CNS) and are a key component of the peripheral nervous system (PNS). They serve as relay points and processing centers for nerve signals. There are two main types of ganglia: sensory ganglia, which contain the cell bodies of sensory neurons, and autonomic ganglia, which contain the cell bodies of autonomic neurons. Sensory ganglia transmit sensory information to the CNS, while autonomic ganglia help regulate involuntary functions such as heart rate, digestion, and respiratory rate. Ganglia thus play a crucial role in both sensory and autonomic pathways of the PNS.