The sense of touch is truly remarkable because it combines multiple sensory experiences into one. When you touch an object, you can feel its temperature, shape, texture, weight, and movement. The same tissues in your body that detect temperature also sense pressure, texture, and pain, all independently from your other senses. If you look at the object, you gain even more information, such as its color and shape.
This incredible sensory information is made possible by the nervous system, one of the most complex systems in the body. It not only manages sensory input but also controls motor functions and other vital processes. The nervous system operates at lightning speed, with some impulses traveling as fast as 120 meters per second, faster than a racecar. This rapid signaling is facilitated by neurons, the cells that make up the nervous system.
Today, let’s delve into how the nervous system transmits information so quickly, focusing on neurons and the exciting research aimed at recreating the sense of touch in laboratories. Previously, we discussed how different messages are sent throughout the body, emphasizing cellular communication. However, the complexity of the nervous system’s communication deserves its own detailed exploration.
The nervous system is designed to transmit messages rapidly from one point to another. For example, touching an object sends signals of temperature, pressure, or vibration to the brain, while stepping on something sharp sends pain signals. Regardless of the direction, the nervous system is structured for speed and consists of two main components: the central nervous system and the peripheral nervous system.
The central nervous system includes the brain and spinal cord. When the brain sends a signal to move your arm, the impulse travels down the brainstem and into the spinal cord, which extends to the lower back. This impulse eventually reaches the muscles it controls, such as the femoral nerve controlling the quadriceps muscles.
The spinal cord has two nerve roots: the ventral root, which sends motor messages from the brain, and the dorsal root, which transmits sensory information to the brain. After passing through these roots, we enter the peripheral nervous system, a complex network of nerves branching throughout the body.
The peripheral nervous system includes cranial nerves that connect directly to the brain, linking to the eyes, ears, and face. Once in the peripheral nervous system, nerves travel to their target tissues, where they perform different functions. Some fibers send motor signals from the brain to muscles or glands, while others carry sensory signals from the skin, eyes, or other organs.
Neurons, often called the electrical wires of the nervous system, are living, metabolizing cells. They contain structures like the nucleus, mitochondria, and other organelles. Neurons have specialized parts that facilitate message transmission, including dendrites, axons, the myelin sheath, and axon terminals.
Dendrites collect chemical signals from other cells, which then send an electrical impulse down the axon. Axons may be coated with myelin, which speeds up impulse transmission. When the impulse reaches the axon terminal, it triggers the release of chemicals into the synapse, the junction with the next neuron. Our bodies use neurotransmitters, a chemical language, to communicate and signal neurons to perform various functions.
Neurotransmitters are made from diverse chemicals and amino acids, with dozens identified. For example, serotonin and dopamine are known for regulating mood but also have other roles. Acetylcholine is crucial for the autonomic nervous system, while GABA is a common inhibitory neurotransmitter. Each neurotransmitter fits into specific receptors, allowing for precise signaling.
Understanding how touch receptors function can help address challenges in medical technology. Recent research published in Scientific Reports focused on restoring the sense of touch for individuals with forearm amputations using advanced robotics. After an amputation, individuals lose the sense of touch, affecting their quality of life. Prosthetic hands have advanced significantly, successfully transmitting sensory cues from the prosthetic to the user’s brain.
However, further improvements are needed to create a more lifelike connection to peripheral nerves. A research team in Italy developed a technique called morphological neural computation to enhance prosthetic hand design. Their design uses a robotic fingertip to gather sensory information, converting it into an electrical pattern that mimics natural sensations, and relaying that signal to electrodes implanted in the patient’s arm stump. This new stimulation method allowed patients to detect fine details consistently.
In the next exploration, we will delve into how the brain processes the information received from the nervous system. Thank you for engaging with this fascinating journey into the world of touch and the nervous system.
Build a 3D model of a neuron using materials like clay, wires, and beads. Focus on accurately representing the different parts such as dendrites, axons, and the myelin sheath. This hands-on activity will help you visualize and understand the structure and function of neurons in the nervous system.
Engage with a virtual reality simulation that allows you to explore the nervous system. Navigate through the central and peripheral nervous systems to see how signals travel. This immersive experience will deepen your understanding of how sensory and motor functions are managed.
Participate in a role-playing game where you act as different neurotransmitters. Each student will represent a specific neurotransmitter, and you’ll work together to simulate how signals are transmitted in the nervous system. This activity will help you learn about the diverse roles of neurotransmitters in a fun and interactive way.
Analyze a case study on the advancements in prosthetic technology for restoring the sense of touch. Discuss the challenges and breakthroughs in creating lifelike connections to peripheral nerves. This activity will enhance your understanding of current research and its implications for medical technology.
Engage in a group discussion about how the sense of touch integrates with other senses to form a complete perception of the environment. Share insights and examples of how sensory information is processed and interpreted by the brain. This collaborative activity will encourage critical thinking and application of the concepts learned.
Here’s a sanitized version of the transcript, removing any informal language and extraneous comments while maintaining the core content:
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One of the remarkable aspects of the sense of touch is that it encompasses multiple senses combined into one. For example, when I handle an object, I can detect its temperature, shape, texture, weight, and movement. The same tissue that senses temperature also detects pressure, texture, and pain signals, all independently from my other senses. If I were to look at the object, I would gain additional information such as color and further confirm its shape.
This sensory information is possible due to the nervous system, one of the most intricate bodily systems, which also manages motor control among other functions. The nervous system operates quickly, with some impulses traveling up to 120 meters per second, which is faster than a racecar. This rapid and diverse signaling is facilitated by neurons, the cells that comprise the nervous system.
Today, we will explore how the nervous system transmits information quickly, focusing on neurons and how scientists are working to reconstruct the sense of touch in the lab. In previous discussions, we covered how different messages are sent throughout the body, emphasizing cellular communication. We did not address how the nervous system communicates messages, as its complexity warrants an entire episode.
The nervous system is designed to transmit messages from point A to point B rapidly. Point A could refer to the brain, while point B could refer to muscles or vice versa. For instance, touching an object sends signals of temperature, pressure, or vibration back to the brain, while stepping on an object can send pain signals. Regardless of the direction, the nervous system is structured for speed, consisting of two main components.
We begin with the brain and spinal cord, which form the central nervous system. In this episode, we will focus on how the brain sends a signal to the arm to initiate movement. This impulse travels down the brainstem and into the spinal cord, which ends at the top of the lower back. The impulse eventually reaches the anatomy it innervates, such as the femoral nerve innervating the quadriceps muscles.
The spinal cord has two nerve roots: the ventral root, which sends motor messages from the brain, and the dorsal root, which transmits sensory information to the brain. The terms dorsal and ventral refer to back and front, respectively. After passing through the spinal roots, we enter the peripheral nervous system, which consists of the neurons branching into a complex network of nerves.
The peripheral nervous system includes nerves that branch directly from the brain, connecting to the eyes, ears, and face, known as cranial nerves. Once in the peripheral nervous system, nerves head toward their target tissues, where we observe differences in function. There are fibers that send motor signals from the brain to muscles or glands, and sensory signals coming from the skin, eyes, or other organs.
These nerve roots branch into individual neurons, which are the cells responsible for transmitting impulses throughout the body. Neurons are often referred to as the electrical wires of the nervous system, but they are living, metabolizing cells. At the cellular level, we observe structures like the nucleus, mitochondria, and other organelles. Neurons also have specialized structures that facilitate message transmission, including dendrites, axons, the myelin sheath, and axon terminals.
Dendrites collect chemical signals from other cells, which then send an electrical impulse down the axon. Axons may be coated with myelin, which enhances the speed of impulse transmission. When the impulse reaches the axon terminal, it stimulates the release of chemicals into the synapse, the junction with the next neuron. Our bodies communicate using a language of chemicals, known as neurotransmitters, which signal neurons to perform various functions.
Neurotransmitters are made from diverse chemicals and amino acids, with at least dozens identified. For example, serotonin and dopamine are known for their roles in regulating mood, but they also have other functions. Acetylcholine is important for the autonomic nervous system, while GABA is a common inhibitory neurotransmitter. Each neurotransmitter fits into unique receptors, allowing for specific signaling.
Neurons interface with a variety of tissues, and different sensory receptors exist within the same sense. Understanding how touch receptors function can help address challenges in medical technology. Recent research published in *Scientific Reports* focused on restoring the sense of touch for individuals with forearm amputations using advanced robotics. Following an amputation, individuals lose the sense of touch, impacting their quality of life. Prosthetic hands have advanced significantly, successfully transmitting sensory cues from the prosthetic to the user’s brain.
However, improvements are still needed to create a more lifelike connection to peripheral nerves. A research team in Italy developed a technique called morphological neural computation to enhance prosthetic hand design. Their design utilizes a robotic fingertip to gather sensory information, converting it into an electrical pattern that mimics the sensations that would have been felt by natural fingers, relaying that signal to electrodes implanted in the patient’s arm stump. This new stimulation method allowed patients to detect fine details consistently.
In the next video, we will explore how the brain processes the information received from the nervous system. Thank you for watching this episode of Seeker Human.
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This version maintains the educational content while removing informal expressions and personal anecdotes.
Touch – The sense by which contact with the external environment is perceived, primarily through the skin. – The study of touch in humans involves understanding how sensory receptors in the skin transmit signals to the brain.
Nervous – Relating to the network of nerve cells and fibers that transmits nerve impulses between parts of the body. – The nervous system is crucial for coordinating voluntary and involuntary actions in the body.
System – A group of interacting or interrelated entities that form a unified whole, especially in biological contexts. – The circulatory system works in tandem with the respiratory system to deliver oxygen to cells throughout the body.
Neurons – Specialized cells transmitting nerve impulses; a nerve cell. – Neurons communicate with each other through synapses, forming complex networks in the brain.
Neurotransmitters – Chemical substances that transmit signals across a synapse from one neuron to another. – Dopamine is a neurotransmitter that plays a significant role in reward and motivation pathways in the brain.
Sensory – Relating to sensation or the physical senses; transmitted or perceived by the senses. – Sensory neurons are responsible for converting external stimuli into internal electrical impulses.
Signals – Electrical or chemical impulses that carry information between neurons and other cells. – The brain processes signals from sensory organs to interpret the environment.
Communication – The process by which information is exchanged between individuals through a common system of symbols, signs, or behavior. – Neuronal communication is essential for the functioning of the nervous system.
Brain – The organ located in the skull that is the center of the nervous system in all vertebrate and most invertebrate animals. – The brain is responsible for processing sensory information and coordinating bodily functions.
Prosthetic – An artificial device that replaces a missing body part, which may be lost through trauma, disease, or a condition present at birth. – Advances in prosthetic technology have enabled the development of limbs that can be controlled by neural signals from the brain.
