Search results
Results from the WOW.Com Content Network
Depiction of smooth muscle contraction. Muscle contraction is the activation of tension-generating sites within muscle cells. [1] [2] In physiology, muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in muscle length, such as when holding something heavy in the same position. [1]
The sliding filament theory explains the mechanism of muscle contraction based on muscle proteins that slide past each other to generate movement. [1] According to the sliding filament theory, the myosin ( thick filaments ) of muscle fibers slide past the actin ( thin filaments ) during muscle contraction, while the two groups of filaments ...
Smooth muscle contraction is caused by the sliding of myosin and actin filaments (a sliding filament mechanism) over each other. The energy for this to happen is provided by the hydrolysis of ATP. Myosin functions as an ATPase utilizing ATP to produce a molecular conformational change of part of the myosin and produces movement.
It is usually due to ion channels in the cell membrane that spontaneously open and close (e.g. If channels in cardiac pacemaker cells). When the membrane potential reaches depolarization threshold an action potential (AP) is fired, excitation-contraction coupling initiates and the myocyte contracts. [citation needed]
To test the reflex, the muscle should be in a neutral position. The muscle being tested needs to be flexed for the clinician to locate the tendon. After the muscle is relaxed, the clinician strikes the tendon. The response should be contraction of the muscle. If this is the knee jerk reflex, the clinician should observe a kick.
Movement of organelles in Tradescantia stamen hair cells. Cytoplasmic streaming, also known as cyclosis, is the active movement of a cell's contents along the components of the cytoskeleton. While mainly seen in plants, all cell types use this process for transportation of waste, nutrients, and organelles to other parts of the cell.
Fused tetanus is when there is no relaxation of the muscle fibers between stimuli and it occurs during a high rate of stimulation. [5] A fused tetanic contraction is the strongest single-unit twitch in contraction. [6] When tetanized, the contracting tension in the muscle remains constant in a steady state. This is the maximal possible ...
The development of the neuromuscular junction requires signaling from both the motor neuron's terminal and the muscle cell's central region. During development, muscle cells produce acetylcholine receptors (AChRs) and express them in the central regions in a process called prepatterning.