When stimulating the gastrocnemius muscle What happens to the number of fibers producing action potentials as we increase voltage?
Terms in this set (18) The sciatic nerve is a bundle of nerve fibers. If you stimulated the nerve, what would happen to the number of fibers producing action potentials as you increased the voltage? The number of fibers producing action potentials would also increase because more voltage gated channels would open.
Why does stimulation on the exterior of the upper thigh produce a twitch in the gastrocnemius muscle?
For example, the gastrocnemius is innervated by hundreds of motor neurons in the sciatic nerve. Each motor neuron has a threshold voltage for activation. If a neuron is stimulated with a single, small supra-threshold voltage, a single all-or-none contraction occurs in all myocytes of a motor unit. This is a twitch.
Why is the threshold for producing a muscle twitch lower when stimulating the sciatic nerve compared to stimulating the muscle directly?
The difference between the two is that directly stimulating the muscle will only recruit fibers in the proximity of the electrodes, whereas the fibers recruited via the sciatic nerve will be more structurally uniform throughout the muscle. Either of these stimulating techniques can be used to perform this exercise.
What happens when muscles contract in frog?
The limb muscles of a frog produce high levels of power to propel the animal into the air during a jump. To do this, they generate large forces quickly, and contract over relatively long distances (up to 30% of their resting length).
What is the force generated when a skeletal muscle is stimulated to contract called?
To move an object, referred to as a load, the muscle fibers of a skeletal muscle must shorten. The force generated by a contracting muscle is called muscle tension.
What type of motor neuron stimulates skeletal muscle fibers to contract by the excitation contraction mechanism?
Alpha motor neurons (also called lower motor neurons) innervate skeletal muscle and cause the muscle contractions that generate movement.
What is gastrocnemius muscle?
The main muscles in the calf are: Gastrocnemius: This muscle is just under your skin at the back of the lower leg. Because the gastrocnemius is close to the skin’s surface, you can often see its outline. It forms the bulk of your calf muscle.
Why is gastrocnemius called the calf muscle?
It takes its name from the Greek words γαστήρ (gaster) meaning stomach or belly, and κνήμη (kneme) meaning leg; the combination of the two words means the “belly of the leg” or in other words the bulk of the calf.
What happens when muscles contract?
During a concentric contraction, a muscle is stimulated to contract according to the sliding filament theory. This occurs throughout the length of the muscle, generating a force at the origin and insertion, causing the muscle to shorten and changing the angle of the joint.
How is skeletal muscle recovery different after moderate activity?
How is skeletal muscle recovery different after moderate activity compared to sustained activity at higher levels ? After moderate activity , it mat take several hours for a muscle fiber to recover. After sustained activity at higher levels, complete recvovery cna take a week.
Which nerves stimulate skeletal muscle?
In the body, skeletal muscles are stimulated to contract by somatic motor nerves that carry signals in the form of nerve impulses from the brain or spinal cord to the skeletal muscles (Fig.
Why does the muscle contract more as the voltage increases?
This is so because more and more of the muscle mass is stimulated as the voltages increase. At high stimulus voltages, the muscle response reaches maximum amplitude. The muscle response does not continue to increase with increasing stimulus voltages because the muscle is already functioning at the best of its ability.
What happens when the nerve supplying a muscle is stimulated?
Muscle activation: The motor nerve stimulates an action potential (impulse) to pass down a neuron to the neuromuscular junction. This stimulates the sarcoplasmic reticulum to release calcium into the muscle cell.
Why does the muscle contraction increase correspondingly with the increment of the stimulus intensity between the threshold and maximal stimulus?
The threshold is that intensity (voltage) of stimulus which brings response. As the intensity (voltage) of the stimulus is increased above the threshold, more and more fibers are stimulated and the response becomes greater and greater.
Why does a skeletal muscle eventually fatigue with constant stimulation?
Anaerobic glycolysis is of central importance in muscle fatigue because it is turned on rapidly during activity, and the net reaction is breakdown of glucose units to lactate ions and protons causing the early acidosis associated with rapid-onset muscle fatigue.
What happens when a muscle fatigues?
Muscle fatigue is a symptom that decreases your muscles’ ability to perform over time. It can be associated with a state of exhaustion, often following strenuous activity or exercise. When you experience fatigue, the force behind your muscles’ movements decrease, causing you to feel weaker.
Where does a muscle receive the energy from to contract?
Abstract. The energy required for muscle contraction is provided by the breakdown of ATP but the amount of ATP in muscles cells is sufficient to power only a short duration of contraction.