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Force Generation Mechanism of Skeletal Muscle Contraction
Published in Yuehong Yin, Biomechanical Principles on Force Generation and Control of Skeletal Muscle and their Applications in Robotic Exoskeleton, 2020
Tendon organ, also called as Golgi tendon organ, is the receptor that feeds back muscle contraction force. It is located on the joint part between skeletal muscle and muscle tendon. Different from muscle spindle, they are not dominated by motoneuron, and the ending afferent nerve is Ib type. Besides, tendon organ is sensitive to the changing rate of contraction force instead of absolute magnitude. The firing strength of the afferent ending is proportional to the increasing rate of contraction force. In stretch reflex, the excitation of muscle spindle is positive feedback; i.e., it enforces the firing of motoneuron, thus strengthening the contraction to resist stretching. The excitation of tendon organ is negative feedback through interneuron, in order to restrain the firing of α motoneuron and to avoid muscle strain.
Spinal Cord and Reflexes
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
The stretch reflex exemplified in Figure 11.9 is also activated by a slow, sustained stretch that would evoke discharges from both the primary and secondary spindle receptors, thereby exciting α-motoneurons of the muscles involved. The increased force of contraction opposes the stretch and restores the muscle length, as well as the activity of the spindle receptors, back to their pre-stretch levels. This slow stretch reflex, mediated by the length-dependent component of the response of muscle spindles, is referred to as the tonic stretch reflex.
IoT-based patient stretcher movement simulation in smart hospital using type-2 fuzzy sets systems
Published in Production Planning & Control, 2023
C. B. Sivaparthipan, M. Anand, Nidhi Agarwal, Mallika Dhingra, Laxmi Raja, Akila Victor, S. A. Amala Nirmal Doss
The bariatric algorithm is used when the above conditions are met. The first one is that the patient’s functional activity is dependent, and they can partially bear their weight. Then, they may not be cooperative but must understand the instruction. The guider must avoid the shearing force, and for all patients, the move should be ½ lower than the destination surface. The patient’s position is the right width, and make sure for it because the excess need from the caregiver is not required. The speciality beds are not used if transferring the patient from one place to another. In this case, the bariatric sling is used. We can’t move stretchers with the heavy weight of the patients for transferring. Alias with using a traditional stretcher, we can use a bariatric stretcher to transfer patients from one place to another, even if the patient is overweight (Tezel, Bilge, and Özkan 2021). The stretch reflex, also known as the myotatic reflex, is the increase in contractility of a muscle in response to passive stretching as long as the strain is within physiological limitations. When a stretch reflex is activated, it generates not only the contraction of the synergistic muscles but also relaxation, i.e. an inhibitory impact on the antagonist’s muscles. The impulse is delivered from the stretched muscle spindle to the alpha motor neuron when a stretch reflex occurs.
Occupant–vehicle dynamics and the role of the internal model
Published in Vehicle System Dynamics, 2018
The simultaneous activation of alpha- and gamma-motoneurons is known as coactivation. In the absence of disturbances and uncertainties the expected muscle length will match exactly the actual muscle length and stretch reflex action will not occur. However if disturbances cause the actual muscle length to change unexpectedly, the change in length is sensed by the muscle spindles which activate the muscle, via the alpha-motoneurons in the spinal cord, to compensate the disturbances and minimise the change in length. Stretch reflex action can be observed easily by tapping the quadriceps tendon just below the kneecap.