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Nerves
Nerves are thread-like structures that form a network of pathways that transmit information from the brain to the body and the body to the brain, in the form of electrical impulses.
1,605 Questions
Upper motor neurons: they are the motor cells of cerebral cortex and subcortical centres whose axons constitue the pyramidal and extra-pyramidal tracts(which then descend to end around the motor nuclei of cranial nerves in brainstem and anterior horn cells of the spinal cord)
Lower motor neurons: they are the cells of motor nuclei of cranial nerves and anterior horn cells of spinal cords, and their axons which constitute the motor fibres of the peripheral nerves that terminate in the motor end plate of striated muscles.
What are the importance of neuron?
Neurons are considered the building block of the brain, but also constitute the spinal column, and nerves. They are important because they transmit messages in our nervous system (sensory and motor).
What is the Function of Neurons?
Sensory neurons relay information from sense organs, motor neurons carry impulses to muscles and glands, and inter-neurons transmit impulses between sensory and motor neurons. A typical neuron consists of dendrites (fibres that receive stimuli and conduct them inward), a cell body (a nucleated body that receives input from dendrites), and an axon (a fibre that conducts the nerve impulse from the cell body outward to the axon terminals). Both axons and dendrites may be referred to as nerve fibres. Impulses are relayed by neurotransmitter chemicals released by the axon terminals across the synapses (junctions between neurons or between a neuron and an effector cell, such as a muscle cell) or, in some cases, pass directly from one neuron to the next. Large axons are insulated by a myelin sheath formed by fatty cells called Schwann cells. Bundles of fibres from neurons held together by connective tissue form nerves.
For more information on neurons, visit Britannica.com.
Are neurons made up of neurolemma?
No. Neurons have a cover on a part called the axon. This is called a neurolemma. Not all axons have this covering. This cover acts like the cover on an electrical cord. It prevents it from short circuiting and increases the speed which the impulse travels.
What is the Function of upper motor neurons?
Upper motor neurons are responsible for initiating voluntary movements by sending signals from the brain to the lower motor neurons in the spinal cord. They play a crucial role in coordinating and executing motor functions throughout the body. Dysfunction of upper motor neurons can result in symptoms such as muscle weakness, spasticity, and impaired coordination.
How is a nerve impulse carried?
Nerve impulses are signals carried along nerve fibers. These signals convey, to the spinal cord and brain, information about the body and about the outside world. They communicate among centers in the central nervous system and they command your muscles to move.
Nerve impulses are electrochemical events. Observed as an electrical event, a nerve impulse is called an action potential (AP) because it involves a change in electrical potential that moves along the nerve cell. It can be measured as an electrical potential difference between the inside and the outside of a nerve fiber. That option has not been generally available to the beginning student. Instead, the nerve impulse has ordinarily been observed as a voltage change along the outside of the sciatic nerve of the common grass frog, Rana pipiens.
Rana pipiens and its relatives have long been favorite subjects for introducing students to the physiology of nerve and muscle. For serious investigations, use of frogs will continue to be justified, but the consumption of this resource for routine teaching ought now to be reduced, for at least three convincing reasons:
- Computing power has become so effective and so generally available that some essential concepts of nerve electrophysiology can as well or better be conveyed by simulation and example rather than by use of live material.
- In the frenzy of trying to make the real specimen perform properly during a student exercise, important ideas are often omitted or are lost because of equipment failure or operator ineptitude.
- Frog populations worldwide appear to be diminishing at an alarming rate, and biologists, of all people, ought not abet this decline.
Topics 1-11 afford a review of some aspects of single-neurone transmembrane characteristics. With this background,the student is prepared to appreciate the whole-nerve behavior illustrated in topics 12-30. The latter are based on actual cathode-ray-oscilloscope records of the type obtained by students in a laboratory course.
this info was taken off http://www.bio.fsu.edu/easton/intro.html
In what phase of meiosis does synapses occur?
Synapsing occurs during Prophase 1, it is when the homologs line up beside each other and form a zipper-like connection between each other. This zipper-like connection is called a "chiasmata." During synapsing "crossing over" can occur. Crossing over is when the chromosomes overlap one another at a certain point, the chromosomes will then exchange a certain part of their arm with the other chromosome's arm. This happens differently everytime, so increasing the diversity of the offspring. Hopefully, this is not too confusing. Once you see a diagram illustrating crossing over, it is really rather simple to understand. Have fun learning!
The nucleus is found in what specific part of the neuron?
The nucleus is found in the cell body or soma of a neuron. It contains the genetic material of the neuron and is responsible for regulating cellular activities.
Does the epilepsy have anything to do with nerve cell?
yes, epilepsy cause by the disruption in the conductance of the impulses by the nerve cells. Imbalance between the inhibition and the excitation of the nerve impulse in the brain cause epilepsy.
What happens to a muscle when an electrical impulse from a nerve stops?
When the electrical impulse from a nerve stops, the muscle relaxes and returns to its resting state. This is because the nerve impulse initiates the release of calcium ions in the muscle cells, leading to muscle contraction. When the nerve impulse stops, the calcium ions are reabsorbed, causing the muscle to relax.
Bipolar neurons are a type of nerve cell with two processes, one acting as the dendrite (receiving end) and the other as the axon (transmitting end). These neurons are commonly found in special sensory organs like the eyes, nose, and ears, where they help relay sensory information to the brain. The bipolar structure enables them to transmit signals in a directional manner.
Rapid communication throughout the body is accomplished by?
Rapid communication throughout the body is accomplished by the nervous system. This system consists of neurons that transmit electrical signals, allowing for quick and precise communication between different parts of the body. Additionally, the endocrine system uses hormones to regulate various bodily functions over a longer period of time.
What is another name for a bundle of neurons?
Rarley i have heard them be called "nervous cells" but nothing else
What is the basic function of a neuron?
Neurons are the basic building blocks of the nervous system and transmit signals between different parts of the body. They receive information from sensory organs, process it, and send out signals to muscles, glands, or other neurons. This allows for communication and coordination within the body.
The Neurons that carry messages to the brain are called?
The neurons that carry messages to the brain are called sensory neurons. They transmit information from sensory receptors in the body to the brain for processing and interpretation.
When the heart stops beating due to interference of it's electrical impulse?
When cardiac muscle contraction is out-of-sync, causing chaotic contractions across the whole of the heart, preventing it from beating and pumping blood, this is called fibrillations. This typically happens when a myocardial infarction (blood clot leading to a heart attack) blocks blood to the coronary arteries, resulting in hypoxia to certain muscle cells. Then, after medical intervention, when the coronary arteries are unblocked and blood supply returns, some cardiac tissue beats out of sync with the rest of the heart, resulting in fibrillations. The usual treatment for this is the use of a defibrillator. This device sends a strong electrical signal into the heart, stopping it momentarily. Then, the brain can send a signal to the SA (sinoatrial) node of the heart to restart it again, so that the heart beats properly again.
Do some neurons lack an axon and communicate only with adjacent neurons?
If they are neurons they have an axon, some cell types do communicate using gap-junctions.
Yes, some complex sensory organs ( in the retina and organ of Corti for example) do not have axons. These cells liberate transmitter from their soma directly onto postsynaptic neurons in proportion to the membrane potential change they experience.
In what ways are neurons similar to other cells?
Neurons vs. Other Cells Similarities with other cells:
- Neurons and other body cells both contain a nucleus that holds genetic information.
- Neurons and other body cells are surrounded by a membrane that protects the cell.
- The cell bodies of both cell types contain organelles that support the life of the cell, including mitochondria, Golgi bodies, and cytoplasm.
- Unlike other body cells, neurons stop reproducing shortly after birth. Because of this, some parts of the brain have more neurons at birth than later in life because neurons die but are not replaced. While neurons do not reproduce, research has shown that new connections between neurons form throughout life.
- Neurons have a membrane that is designed to sends information to other cells. The axon and dendrites are specialized structures designed to transmit and receive information. The connections between cells are known as a synapses. Neurons release chemicals known as neurotransmitters into these synapses to communicate with other neurons.
Synapses are essential for communication between neurons in the brain. They allow for the transmission of information through the release of neurotransmitters, which enable electrical signals to be passed from one neuron to another. This process is crucial for functions like learning, memory, and overall brain function.
Structure that carries the heart electrical impulse into the ventricle?
The structure that carries the heart's electrical impulse into the ventricles is called the bundle of His. It is a collection of specialized muscle fibers located in the walls of the heart's chambers that conducts the electrical signal from the atrioventricular node to the ventricles, initiating their contraction.
The chemical released by the axon that travels across a synapse and binds to dendrites or cells is called a neurotransmitter. Neurotransmitters play a crucial role in transmitting signals between neurons and regulating various physiological processes in the body.
What are the Stages of nerve impulses?
The action potential has 5 main phases:
1) stimulation/rising phase - depolarization caused by influx of sodium ions at the axon hillock; potential increases from a resting potential of -70 mV2) peak phase - depolarization and membrane potential reaches a peak, with sodium channels open maximally, at about +40 mV
3) falling phase - potassium channels open in response, causing a subsequent reduction in membrane potential, and the neuron begins to repolarize
4) hyperpolarization/undershoot phase - more potassium channels stay open after sodium channels close, causing a hyperpolarization of the neuronal membrane, bringing the potential down below its initial resting potential (below -70 mV)
5) refractory phase - potassium channels begin to close, allowing the membrane potential to revert back to the resting potential of -70 mV; during this phase, the probability of the nerve being able to refire is extremely low, thus allowing for a delay between action potentials
What is the function of the motor neuron?
Motor neurons are responsible for transmitting signals from the brain and spinal cord to muscles or glands throughout the body. They play a crucial role in controlling muscle contractions, movements, and various bodily functions.
The Schwann cell forms a myelin sheath around the?
axons of neurons in the peripheral nervous system. The myelin sheath helps to insulate the axon and improve the speed of electrical signal conduction along the neuron. Schwann cells are also involved in nerve regeneration and support neuron function within the peripheral nervous system.
