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The principle that governs this is called the All-or-none Law.
The best way to explain how it works may be best illustrated by an analogy. Are you familiar with how a spark of electricity can jump a gap? Or how lighting seems to come down as a huge flash? Both of these are acting very much like what a muscle cell must do to contract. The impulse that triggers either of these is electrical, and so it needs so have a certain amount of charge to be strong enough to jump either the gap between two wires or between the clouds and the ground and crash down as lighting. Just like you can't have just a little bit of lightening, a muscle cannot do just a little bit of contracting, it has to do it all or do none at all. So it waits until the current is strong enough to run the length of its sarcomeres in the myofibrils that make up the muscle cell and it gives it all its got.
The reason this may seem counterintuitive is that we rarely ever experience just one single muscle cell contract because they usually act in a group called a motor unit. You can think of a motor unit as a taxi cab service, and when it goes out to do its job it sends all of its taxis (muscle fibers in its company) to do all the work they can. The way you contract a muscle made of many motor units that are made of many individual cells is that the central nervous system select how many motor units (taxi companies) it calls into action. To us it feels like we are using different amounts of effort, but we are just selecting how many companies of taxi cabs (motor units) to call into action. To the taxi cars, themselves, they are all driving around at their highest capacity, just like the all-or-none law says they should.
What else can I help you with?
What is a stimulus that results in no perceptible contraction?
A subthreshold stimulus is one that does not generate a strong enough signal to elicit a perceptible contraction in muscle fibers. It is below the threshold required to cause an action potential and result in muscle contraction.
What stimulus below this intensity will result in no response in a neuron?
Any stimulus below the neuron's threshold potential will not result in a response, as it is not strong enough to generate an action potential. Neurons require a minimum level of stimulus intensity to reach the threshold potential and fire an action potential.
Stimulus threshold of the neuron refers to what?
The stimulus threshold of a neuron, often referred to as the action potential threshold, is the minimum level of stimulation required to trigger an electrical impulse (action potential) in the neuron. When a stimulus exceeds this threshold, it causes sufficient depolarization of the neuron's membrane, leading to the rapid influx of sodium ions and the subsequent propagation of the action potential along the axon. If the stimulus is below this threshold, the neuron remains inactive, and no action potential is generated.
What is stimulus threshold?
ST - In regards to excitable cell (i.e. neurons) the minimum mV need to trigger a AP (action potential) and is around -40mV (although this may vary depending on the cell). In additional to this; excitable cells (i.e. neurons) shows an all-or-nothing property, such that if the stimulus threshold is not met the action potential will not be created.
Minimum level of stimulation required to trigger a neural impulse?
The minimum level of stimulation required to trigger a neural impulse is known as the "threshold." This threshold is the minimum amount of neurotransmitter release or electrical stimulation needed to generate an action potential in a neuron. Below this threshold, the neuron will not fire an action potential.
What is a stimulus that results in no perceptible contraction?
A subthreshold stimulus is one that does not generate a strong enough signal to elicit a perceptible contraction in muscle fibers. It is below the threshold required to cause an action potential and result in muscle contraction.
Threshold stimulus is defined as the?
Threshold stimulus is defined as the minimum level of stimulus intensity that is required to trigger a response in a neuron or muscle fiber. This level must be reached for action potentials to be generated, leading to muscle contraction or nerve signal transmission. If the stimulus is below this threshold, no response occurs, highlighting the all-or-nothing principle of action potentials.
What stimulus below this intensity will result in no response in a neuron?
Any stimulus below the neuron's threshold potential will not result in a response, as it is not strong enough to generate an action potential. Neurons require a minimum level of stimulus intensity to reach the threshold potential and fire an action potential.
Stimulus threshold of the neuron refers to what?
The stimulus threshold of a neuron, often referred to as the action potential threshold, is the minimum level of stimulation required to trigger an electrical impulse (action potential) in the neuron. When a stimulus exceeds this threshold, it causes sufficient depolarization of the neuron's membrane, leading to the rapid influx of sodium ions and the subsequent propagation of the action potential along the axon. If the stimulus is below this threshold, the neuron remains inactive, and no action potential is generated.
Do Muscle organs obey the all-or-none law?
Yes, muscle fibers obey the all-or-none law, which states that when a muscle fiber is stimulated to threshold, it will contract fully; if the stimulus is below threshold, it will not contract at all. This principle applies to individual muscle fibers, but whole muscles can exhibit graded responses based on the number of fibers recruited and the frequency of stimulation. Thus, while each muscle fiber follows the all-or-none law, the overall muscle action can vary in strength.
What is the definition of a submaximal stimulus?
A submaximal stimulus refers to an intensity level of a stimulus that is below the maximum level that a system or organism can respond to. It is often used in exercise physiology to describe a workload that does not elicit a maximal performance or physiological response.
What is stimulus threshold?
ST - In regards to excitable cell (i.e. neurons) the minimum mV need to trigger a AP (action potential) and is around -40mV (although this may vary depending on the cell). In additional to this; excitable cells (i.e. neurons) shows an all-or-nothing property, such that if the stimulus threshold is not met the action potential will not be created.
Minimum level of stimulation required to trigger a neural impulse?
The minimum level of stimulation required to trigger a neural impulse is known as the "threshold." This threshold is the minimum amount of neurotransmitter release or electrical stimulation needed to generate an action potential in a neuron. Below this threshold, the neuron will not fire an action potential.
What is a brief auditory or visual signal that occurs below the absolute threshold for that sense?
A brief auditory or visual signal that occurs below the absolute threshold for that sense is known as a subliminal stimulus. These stimuli are presented in such a way that they are below our conscious awareness but may still influence our perception or behavior.
Myofibrils play a fundamental role in what?
Myofibrils play a fundamental role in muscle contraction and generating force in skeletal muscle. They are composed of thick and thin filaments that slide past each other during contraction, causing muscle fibers to shorten and produce movement.
The all or none principle states that?
The all-or-none principle in physiology states that once a nerve impulse reaches a certain threshold, a neuron will fire at its maximum potential. If the stimulus is strong enough to trigger an action potential, the response will occur at full strength. If the stimulus is below the threshold, no response will be triggered.
What is a receptor threshold?
A receptor threshold refers to the minimum level of stimulus intensity required for a sensory receptor to respond and generate an action potential. It determines the point at which a stimulus becomes detectable by the nervous system. Below this threshold, the receptor remains unresponsive, while above it, the receptor can initiate a signal that is transmitted to the brain for interpretation. This concept is crucial for understanding how organisms perceive their environment and respond to various stimuli.
