can nerve impulses travel in both directions

When you get a nerve firing, you have probably heard that it is an electrical impulse that carries the signal. This is true, but it is not electrical in the same way your wall outlet works. This is electrochemical energy. Neurotransmitters are molecules that fit like a lock and key into a specific receptor. The receptor is located on the next cell in the line. When the neurotransmitter hits the receptor on the next cell in line, it signals that cell to begin a firing as well.

This will continue all the way down the length of the nerve track. In a nutshell, a nerve firing results in a chain reaction down the nerve cell's axon, or stemlike section. Sodium (Na+) ions flow in, potassium (K+) ions flow out, and we get an electrochemical gradient flowing down the length of the cell. You can think of it as a line of gunpowder that someone lit, with the flame traveling down the length of it. Common electrical power is more like a hose full of water, and when you put pressure on one end, the water shoots out the other.

Therefore, nerve impulses cannot travel in the opposite direction, because nerve cells only have neurotransmitter storage vesicles going one way, and receptors in one place.

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Addendum to further questions: The impulses travel TO the CNS from the PNS. Do not confuse NERVE signals from the MUSCLE signals! Each goes ONE WAY, but together they coordinate to help use move. The following is a better description of the chemical processes involved: https://web.facebook.com/bryant.seabrooks/videos/10208641612752284/?t=325

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Nerve Impulses: the Key to Understanding the Brain

Impulses are the basis of mind..

Posted October 17, 2019

One of the greatest, relatively underappreciated, discoveries in all of science was the discovery of the nerve impulse in the 1930s by the British Lord Adrian. Adrian did win a Nobel Prize for his discovery in 1932, but scholars underestimated its implications, which go beyond the fact that four later Nobel Prizes were awarded for work based on Adrian’s discovery. This included discovery of sodium and potassium ionic flux during impulses, the role of impulses in releasing neurotransmitters, and the role of membrane ion channels in impulse generation and second messenger cascades.

Like many discoveries in science, this one could not have been made without technological advances. Early studies with inferior technology had a very poor signal-to-noise ratio (not the thick baseline electrical noise in the illustration). Vast improvements in this ratio are obtained with today's technology and intracellular recording. In Adrian's day, the essential advance was the development of the capillary electrometer, which enabled the detection of very small electrical pulses on the order of one-millisecond duration. This instrumentation was crude and far inferior to later advances such as the oscilloscope and computer screens. Before Adrian’s use of the electrometer, scientists generally knew that peripheral nerves generated some kind of electrical signal, but nothing was known about the nature of the signal in individual neurons.

Nerves contain fibers from hundreds of neurons that produce a summed, relatively long duration and large wave that spreads down the nerve. No one knew how the individual nerve fibers contributed to this compound signal. Adrian answered this question by tedious microdissection of nerves into their individual fibers and recording stimulus-evoked responses in a single fiber. What Adrian saw was that the response was a series of voltage pulses, each about one millisecond long, all of the same amplitude in a given fiber. Decades later, the development of microelectrodes enabled confirmation of Adrian’s discovery in neurons in the brain.

This provided evidence of the basic similarity and difference between brains and the later development of computers. Both computers and brains convert the real world into representations. In computers, information is coded, in the form of 1s and 0s, and as nerve impulses in brains. Both computers and brains distribute and process this represented information, and can store it as memories. However, because brains are biological and use impulses to represent information, they can change their circuitry and can self-program. Unlike computers, brains also have will, including a likely degree of free will .

Brains have conspicuous functional states, ranging from intense conscious concentration to drowsiness, to sleep, to coma, to death. Neuronal electrical activity correlates in a systematic way with these state changes. The most conspicuous of these activity measures exist in terms of nerve impulse firing and the extracellular ionic currents they create at synapses, known as field potentials. As these field potentials reach the scalp, they produce the signal we call an electroencephalogram. Field potentials are technologically easier to record than individual nerve impulses, but more ambiguous to interpret because of the spatial summation of voltages from hundreds of heterogeneous neurons.

The original nerve impulse findings were that the rate of impulse firing governed the impact on neuronal targets, whether they be muscle or other neurons. Various labs, including my own, in the 1980s, discovered that the intervals between impulses also contained their own kind of information. For example, my lab reported that some neurons contained statistically significant serial ordering of impulse intervals in a neuron’s impulse stream. The intervals, at least in higher-level brain areas, are not random. They are serially dependent, as if they contained a message. If you are familiar with Markov transition probability, you can understand our finding that serial dependences exist in as many as five successive intervals (Sherry et al. 1982). This led us to suggest “byte processing” as a basic feature of neuronal information processing. This view has not caught on, and most people still seem to think that firing rate is the basic information code, despite the well-established temporal summation that occurs as impulses arrive at synapses. Bernard Katz demonstrated temporal summation of impulse effects in neuromuscular junctions in 1951 and later J.P. Segundo and colleagues confirmed it in neuronal synapses (Segundo et al., 1963).

It should not be surprising that there are serial dependencies in impulse intervals. For example, intracellular recording of postsynaptic potentials revealed that the polarization change caused by a single impulse input decays in a few milliseconds. However, a succession of closely spaced impulse inputs allows the polarization changes to summate.

These days, the emphasis needs to be put on impulse activity in defined circuitry. All neurons are linked in one or more circuits, and the impulse train in any one neuron is only a small part of the over-all circuit activity. The function of any given circuit depends on the circuit impulse pattern (CIP) of the whole circuit. Researchers have developed microelectrodes that allow recording of impulse trains from single neurons, but the problem is in implanting a series of electrodes so that each one monitors the activity of a selected neuron in a defined.

I think that research should focus on CIPs and the phase relationships of electrical activity among cortical circuits, both within and among cortical columns (Klemm, 2011). Nerve impulses have to be at the heart of consciousness, inasmuch as impulses contain the brain’s representation of information and create the synaptic field potentials.

We know from monitoring known anatomical pathways for specific sensations that the brain creates a CIP representation of the stimuli. As long as the CIPs remain active, the representation of sensation or neural processing is intact and may even be accessible to consciousness. However, if something disrupts ongoing CIPs to create a different set of CIPs, as for example would happen with a different stimulus, then the original representation disappears. If the original CIPs persist long enough, a memory could form, but otherwise, the information would be lost. The implication for memory formation is that the immediate period after learning must be protected from new inputs to keep the CIP representation of the learning intact long enough to form a more lasting memory.

Much current research shows that conscious awareness correlates with the degree of synchrony and time-locking of CIPs in various regions and within regions of cortex. The evidence comes from electroencephalographic monitoring of the oscillating field potentials in a given area. These are voltage waves that occur in multiple frequency bands. Phase relationships of voltage waves from different circuits surely reflect the timing of the impulse discharges that create those fields. I summarized the animal research evidence for this view in my first book, some 50 years ago (Klemm, 1969). Depending on the nature of the stimulus and mental state, these oscillations of various circuits may jitter with respect to each other or become time locked. The functional consequence of synchrony has to be substantial, and many others and I suggest that this is a fundamental aspect of consciousness. The correlation between frequency coherences and states of consciousness is clear. Frequency coherence reflects a “binding” of neurons into linked and shared electrochemical activity, but how this relates to conscious awareness will require a next great discovery in science.

Klemm, W. R. (1969). Animal Electroencephalography. New York: Academic Press.

Klemm, W. R. (2011). Atoms of Mind. The “Ghost in the Machine” Materializes. New York: Springer.

Segundo, J. P., et al. (1963). Sensitivity of neurons in Aplysia to temporal pattern of arriving impulses. J. Exp. Biol. 40: 643-667.

Sherry, C. J., Barrow, D. L., and Klemm, W. R. 1982. Serial dependen­cies and Markov processes of neuronal interspike intervals from rat cerebellum. Brain Res. Bull. 8: 163‑169.

William Klemm , Ph.D ., is a senior professor of Neuroscience at Texas A&M University.

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The “Coming Out” of the Electrical Synapse

• by an electrical synapse, in which the two cells touch and are connected by tiny holes, which lets the nerve impulse pass directly from one neuron to the other; or
• by a chemical synapse, where the two cells do not touch and the nerve impulse needs particular molecules to bridge the gap between them.

Chemical synapses are slower than electrical ones but are also far more flexible. This valuable flexibility is the foundation of all learning .

On either side of the synapse, the axon and dendrite have evolved specialized molecules to perform their respective tasks.

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35.4: How Neurons Communicate - Nerve Impulse Transmission within a Neuron- Resting Potential

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Learning Objectives

• Explain the formation of the resting potential in neurons

Nerve Impulse Transmission within a Neuron

For the nervous system to function, neurons must be able to send and receive signals. These signals are possible because each neuron has a charged cellular membrane (a voltage difference between the inside and the outside). The charge of this membrane can change in response to neurotransmitter molecules released from other neurons and environmental stimuli. Any voltage is a difference in electric potential between two points; for example, the separation of positive and negative electric charges on opposite sides of a resistive barrier. To understand how neurons communicate, one must first understand the basis of charged membranes and the baseline or ‘resting’ membrane charge.

Neuronal Charged Membranes

The lipid bilayer membrane that surrounds a neuron is impermeable to charged molecules or ions. To enter or exit the neuron, ions must pass through special proteins called ion channels that span the membrane. Ion channels have different configurations: open, closed, and inactive. Some ion channels need to be activated in order to open and allow ions to pass into or out of the cell. These ion channels are sensitive to the environment and can change their shape accordingly. Ion channels that change their structure in response to voltage changes are called voltage-gated ion channels. Voltage-gated ion channels regulate the relative concentrations of different ions inside and outside the cell. The difference in total charge between the inside and outside of the cell is called the membrane potential.

Resting Membrane Potential

For quiescent cells, the relatively-static membrane potential is known as the resting membrane potential. The resting membrane potential is at equilibrium since it relies on the constant expenditure of energy for its maintenance. It is dominated by the ionic species in the system that has the greatest conductance across the membrane. For most cells, this is potassium. As potassium is also the ion with the most-negative equilibrium potential, usually the resting potential can be no more negative than the potassium equilibrium potential.

A neuron at rest is negatively charged because the inside of a cell is approximately 70 millivolts more negative than the outside (−70 mV); this number varies by neuron type and by species. This voltage is called the resting membrane potential and is caused by differences in the concentrations of ions inside and outside the cell. If the membrane were equally permeable to all ions, each type of ion would flow across the membrane and the system would reach equilibrium. Because ions cannot simply cross the membrane at will, there are different concentrations of several ions inside and outside the cell. The difference in the number of positively-charged potassium ions (K + ) inside and outside the cell dominates the resting membrane potential. When the membrane is at rest, K + ions accumulate inside the cell due to a net movement with the concentration gradient. The negative resting membrane potential is created and maintained by increasing the concentration of cations outside the cell (in the extracellular fluid) relative to inside the cell (in the cytoplasm). The negative charge within the cell is created by the cell membrane being more permeable to K + movement than Na + movement.

In neurons, potassium ions (K+) are maintained at high concentrations within the cell, while sodium ions (Na+) are maintained at high concentrations outside of the cell. The cell possesses potassium and sodium leakage channels that allow the two cations to diffuse down their concentration gradient. However, the neurons have far more potassium leakage channels than sodium leakage channels. Therefore, potassium diffuses out of the cell at a much faster rate than sodium leaks in. More cations leaving the cell than entering it causes the interior of the cell to be negatively charged relative to the outside of the cell. The actions of the sodium-potassium pump help to maintain the resting potential, once it is established. Recall that sodium-potassium pumps bring two K + ions into the cell while removing three Na+ ions per ATP consumed. As more cations are expelled from the cell than are taken in, the inside of the cell remains negatively charged relative to the extracellular fluid.

• When the neuronal membrane is at rest, the resting potential is negative due to the accumulation of more sodium ions outside the cell than potassium ions inside the cell.
• Potassium ions diffuse out of the cell at a much faster rate than sodium ions diffuse into the cell because neurons have many more potassium leakage channels than sodium leakage channels.
• Sodium-potassium pumps move two potassium ions inside the cell as three sodium ions are pumped out to maintain the negatively-charged membrane inside the cell; this helps maintain the resting potential.
• ion channel : a protein complex or single protein that penetrates a cell membrane and catalyzes the passage of specific ions through that membrane
• membrane potential : the difference in electrical potential across the enclosing membrane of a cell
• resting potential : the nearly latent membrane potential of inactive cells

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19 captivating facts about nerve impulse.

Written by Dayna Weintraub

Modified & Updated: 03 Mar 2024

Reviewed by Sherman Smith

• Membrane Potential Facts
• Neurons Facts
• Neurotransmitters Facts

Nerve impulses are the electrical signals that allow information to travel throughout our bodies. They play a crucial role in our daily functioning, from enabling us to move our muscles to allowing us to feel sensations and perceive the world around us. Understanding how nerve impulses work is not only fascinating but also essential in the field of biology and neuroscience.

In this article, we will explore 19 captivating facts about nerve impulses that will deepen your understanding of this intricate biological process. From the minute details of how nerve cells communicate to the astonishing speed at which nerve impulses travel, we will delve into the world of neurons and the remarkable ways in which they function.

Get ready to embark on a journey through the fascinating realm of nerve impulses, as we unravel the mysteries behind these electrical signals and appreciate the complexity of the human nervous system.

Key Takeaways:

• Nerve impulses are like lightning bolts in our bodies, helping us move, feel, and react quickly. They’re super fast and essential for everything from muscle movements to experiencing the world through our senses.
• Understanding nerve impulses is crucial for developing treatments for conditions like multiple sclerosis and epilepsy. Scientists are unraveling their mysteries to improve human health and make groundbreaking medical advancements.

Nerve impulses are the result of electrical changes in neuron membranes.

When a neuron is stimulated, the electrical charge inside the neuron’s membrane changes, creating an electrical impulse that travels along the neuron.

Nerve impulses can travel at speeds of up to 120 meters per second.

Thanks to their incredible speed, nerve impulses allow us to react quickly to stimuli, such as pulling our hand away from a hot surface.

The myelin sheath increases the speed of nerve impulse transmission.

The myelin sheath, a fatty substance that wraps around some neurons, acts as an insulator and facilitates faster conduction of the electrical signal.

Nerve impulses can be either excitatory or inhibitory.

Excitatory nerve impulses stimulate the receiving neuron, while inhibitory impulses prevent the neuron from firing, balancing the overall neural activity.

The process of transmitting nerve impulses is called synaptic transmission.

At the synapse, the junction between two neurons, chemical messengers called neurotransmitters are released to transmit the signal from one neuron to another.

Nerve impulses can be both electrical and chemical in nature.

While the initial impulse within a neuron is electrical, the transmission of the impulse between neurons involves the release and reception of chemical neurotransmitters.

Sodium and potassium ions play a crucial role in nerve impulse transmission.

During the transmission, there is an exchange of sodium and potassium ions across the neuron’s membrane, creating the necessary electrical changes for the impulse to travel.

Nerve impulses can travel in both directions within a neuron.

While the majority of nerve impulses travel in one direction, certain types of neurons allow for bidirectional transmission, enabling more complex neural pathways.

Reflex actions are a result of fast, involuntary nerve impulse transmission.

Reflexes, such as pulling our hand away from a sharp object, occur due to a rapid nerve impulse bypassing the brain and directly triggering a motor response.

Nerve impulses can be amplified and modulated in the brain.

The brain has the remarkable ability to regulate and modify nerve impulses, allowing for intricate processing and interpretation of sensory information.

Nerve impulses are essential for muscle movement and coordination.

From the simplest movements to complex athletic performances, nerve impulses are responsible for initiating and controlling muscle contractions.

The speed of nerve impulse transmission can be affected by various factors.

Temperature, myelin thickness, and the diameter of the nerve fiber can all impact the speed at which a nerve impulse travels.

Chemical substances can alter or block nerve impulse transmission.

Anesthetics and certain drugs can temporarily disrupt nerve impulse transmission by interfering with ion channels or neurotransmitter release .

Nerve impulses play a crucial role in sensory perception.

By transmitting signals from receptors in our sensory organs to the brain, nerve impulses enable us to experience the world through our senses.

Abnormal nerve impulse transmission can lead to neurological disorders.

Conditions such as multiple sclerosis, Parkinson’s disease, and epilepsy are all characterized by disrupted or faulty nerve impulse transmission.

Nerve impulses can be studied through electrophysiology.

Electrophysiology is a branch of science that focuses on the electrical properties and activity of living cells, including the measurement of nerve impulses.

Nerve impulse transmission requires energy.

The active transport of ions and the maintenance of concentration gradients during nerve impulse transmission require a significant amount of cellular energy.

The human brain generates millions of nerve impulses every second.

With billions of neurons firing in the brain at any given moment, the sheer magnitude of nerve impulses being transmitted is awe-inspiring.

Understanding nerve impulses is crucial for advancing medical treatments.

By unraveling the mysteries of nerve impulses, scientists and researchers can develop innovative therapies for neurological disorders and improve overall human health.

In Conclusion

The 19 captivating facts about nerve impulses highlight the remarkable complexity and importance of these electrical signals in our bodies. From the rapid transmission of reflex actions to the intricate processing of sensory information in the brain, nerve impulses play a vital role in our everyday functioning. By delving into the fascinating world of nerve impulses, we gain a deeper appreciation for the incredible workings of the human nervous system .

In conclusion, the process of nerve impulse transmission is truly fascinating and essential for the functioning of our body. From the intricate network of neurons to the complex electrical signals, every aspect plays a crucial role in ensuring the transmission of information throughout our nervous system.We have learned that nerve impulses travel at incredible speeds, allowing for quick responses to external stimuli. The myelin sheath, with its insulating properties, facilitates the rapid conduction of impulses along the axons. Additionally, the actions of ion channels and neurotransmitters ensure the precise and efficient transmission of signals between neurons.Understanding the intricate mechanisms behind nerve impulse transmission not only enhances our knowledge of the human body but also helps in the development of treatments for neurological disorders. The more we delve into the complexities of nerve impulses, the better equipped we become to unlock the mysteries of the nervous system.

1. What is a nerve impulse?

A nerve impulse is an electrical signal that is transmitted through neurons, allowing for communication within the nervous system.

2. How fast does a nerve impulse travel?

A nerve impulse can travel at speeds of up to 120 meters per second, depending on factors such as the diameter of the nerve fiber and the presence of a myelin sheath.

3. What is the role of the myelin sheath in nerve impulse transmission?

The myelin sheath acts as an insulating layer around the axons of some neurons, enabling faster transmission of nerve impulses and preventing the signal from dissipating.

4. How do nerve impulses cross the synapse?

Nerve impulses are transmitted across the synapse through the release of neurotransmitters. These chemical messengers travel from the axon of one neuron to the dendrite of the next, facilitating transmission of the signal.

5. What happens when there is a disruption in nerve impulse transmission?

Disruptions in nerve impulse transmission can lead to various neurological disorders, such as multiple sclerosis or peripheral neuropathy, which can affect motor coordination, sensation, and other bodily functions.

6. Can nerve impulses be consciously controlled?

While involuntary nerve impulses regulate essential body functions, some nerve impulses can be consciously controlled, allowing us to move our muscles voluntarily and perform complex actions.

7. Are all nerve impulses the same?

No, nerve impulses can vary in strength and frequency, depending on the intensity and nature of the stimulus received by the sensory receptors.

8. How does the brain interpret nerve impulses?

The brain interprets nerve impulses based on their strength, frequency, and the specific neural pathways they follow. This interpretation allows us to perceive and react to different sensory stimuli.

9. Can nerve impulses travel in both directions?

While most nerve impulses travel in one direction, from the dendrites to the axon terminals, certain nerves, such as those involved in reflexes, can transmit impulses in both directions.

10. Can nerve impulses be artificially stimulated?

Yes, with the help of various technologies and medical interventions, such as electrical stimulation and nerve implants, it is possible to artificially stimulate nerve impulses in certain situations for therapeutic purposes.

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Why can nerve impulses travel only in one direction?

Nerve impulse: neurons communicate with one another through nerve impulses. nerve impulses are electrical signals that travel along dendrites onward the segment of an axon filament. the movement of ions into and out of the cell produces the action potential. cause of impulse transmission in one direction: nerve impulses only travel in one direction in neurons. this impulse transmission is dependent on synaptic transmission. this happens because nerve cells only have one transmission site. the receptors also work in one direction. the nerve impulse works on the principle of depolarization and repolarization. the nerve cells only have neurotransmitter storage vesicles in one way. nerve impulses must cross synaptic junctions to travel from one cell to another. the nerve cells are lined up in a long track, with the head of one cell connecting to the tail of another. there are tiny gaps between these cells. these tiny gaps are referred to as nerve synapses. when a nerve fires, an action potential is generated along the nerve track. the sodium-potassium pump ejects three sodium ions for every two potassium ions pumped into the cell; energy is needed for this process. it results in an action potential. because neurotransmitter storage vesicles and receptors are present in one location, impulse transmission occurs only in one direction..

At what speed do nerve impulses travel in mammals?