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Why is it only possible to induce an extrasystole during relaxation?
It is only possible to induce an extrasystole during relaxation because the heart needs to be in a certain phase of the cardiac cycle for an extra beat to occur. During relaxation (diastole), the heart muscles are more excitable, making it easier for an extra electrical impulse to trigger a premature contraction. This is why inducing an extrasystole during relaxation is more likely to succeed than during contraction (systole).
The terms systole and diastole refer respectively to the?
Systole refers to the phase of the heartbeat when the heart muscle contracts and blood is pushed out of the heart chambers. Diastole refers to the phase when the heart muscle relaxes and the heart chambers fill with blood.
What period is characterized by calcium ions release into cytosol and depolarization of the sarcolemma and T tubules?
The period that would be characterized by those things would be muscle contraction. Calcium ions are the neurotransmitters that cause contraction. Calcium Ions depolarize the cell and are spread through out the muscle via the T tubules.
What occurs in the latent period of a twitch in a skeletal muscle fiber?
During the latent period of a twitch in a skeletal muscle fiber, the muscle is receiving a signal to contract but has not yet started to generate force or movement. This phase involves the excitation-contraction coupling process, where the action potential triggers the release of calcium ions, leading to the activation of the muscle fibers.
During which portion of the cardiac cycle is it possible to induce extra systole?
Extrasystole is an extra ventricular systole that happens during the begging of relaxation (repolarization). Since the cardiac is able to depolarize only after repolarization, any stimulus upon the repolarization period created an increased ventricular contraction or which is also called extrasystole but not a new contraction.
What phase is between stimulus of a muscle and the shortening of the muscle?
The phase between the stimulus of a muscle and the shortening of the muscle is called the latent phase or latent period. During this phase, the muscle is receiving the signal to contract, but actual muscle shortening has not yet occurred. This period is important for the muscle fibers to prepare and generate enough force for contraction.
What are the three stages of muscle cell contraction?
A Muscle Twitch is a single contraction of skeletal muscle. The three distinct phases are latent, contraction, and relaxation. Latent Phase: Is the interval from the stimulus application until the muscle begins to contract (shorten). Note that there is no traced activity during this phase, but there are some electrical and chemical changes taking place during this phase. Contraction Phase: This phase is when the muscle fibers shorten, the tracings will show during this phase (a) peak(s). Relaxation Phase: This phase is represented by the downward curve in your tracings, this is when the muscle is going back to its original state of relaxation and the muscle will once again lengthen
What is second stimulus before relaxation causes increased force called?
The phenomenon you are referring to is called the second stimulus before relaxation, which causes increased force, is known as the treppe effect or the staircase phenomenon. This is characterized by the successive increase in muscle contraction force when muscle fibers are stimulated with increasing frequency.
What is the contraction phase?
The contraction phase refers to the stage of a muscle action where the muscle fibers shorten and generate force. This is when the muscle is actively contracting and pulling on the tendons to create movement.
What muscle contraction occurs in the biceps brachii during the upward phase of the bicep curl?
a concentric contraction- a concentric contraction involves the muscle length, shortening during a contraction! YA-trick-YA!
What is a concentric contraction?
concentric contraction is atype of muscle contraction which the muscle shortens while genrating aforce The muscle shortens to produce movement. A muscle contraction in which shortening occurs.
What is the premotor phase of reaction time?
The premotor phase of reaction time involves perceiving a stimulus and preparing a response. During this phase, the brain processes information from the environment and plans the motor action required to respond to the stimulus. This phase occurs before the actual execution of the motor response.
What is the name given to contraction phase of the cardiac cycle?
The contraction phase of the cardiac cycle is called systole. This is when the heart muscle contracts to pump blood out of the heart and into the circulatory system.
What is an example of an isotonic contraction?
An Isotonic contraction is when a muscle becomes longer or shorter to produce force and therefore an example is a bicep curl. During the downward phase your muscle (bicep) lengthens and during the upward phase your muscle (bicep) shortens.
Which neurotransmitter is responsible for the excitatory phase of muscle contraction a. dopamine b. serotonin c. GABA d. none of the above?
None of the above. The neurotransmitter responsible for the excitatory phase of muscle contraction is acetylcholine. It is released from motor neurons at the neuromuscular junction to stimulate muscle fibers.
Why is it only possible to induce an extrasystole during relaxation period?
The cardiac muscle is incapable of reacting to any stimulus before approximately in the middle of phase 3. It will not react to a normal cardiac stimulus before phase 4.
What is a brief contraction of all muscle fibers in a motor unit in a response to a single action potientia lmoving down the somatic motor neuron is known as what?
A brief contraction of all muscle fibers in a motor unit in response to a single action potential traveling down the somatic motor neuron is known as a muscle twitch. This twitch consists of three phases: the latent period, contraction phase, and relaxation phase. It represents the basic unit of muscle contraction and is essential for understanding muscle function and physiology.
