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This information can be processed by the brain as proprioception. The responses of muscle spindles to changes in length also play an important role in regulating the contraction of muscles, for example, by activating motor neurons via the stretch reflex to resist muscle stretch. The muscle spindle has both sensory and motor components.
It allows the motor neuron to transmit a signal to the muscle fiber, causing muscle contraction. [2] Muscles require innervation to function—and even just to maintain muscle tone, avoiding atrophy. In the neuromuscular system, nerves from the central nervous system and the peripheral nervous system are linked and work together with muscles. [3]
Many smooth muscle cells in a transverse section through a muscle bundle show regions of very close apposition to adjacent cells at which connexins form junctions between the cells. Unlike in cardiac muscle, where gap junctions are confined to the ends of cardiac myocytes , smooth muscle gap junctions occur along the length of the muscle cells ...
This process maintains the tautness of muscle spindles and is called alpha gamma co-activation. The nuclei of spindle muscle cells are located in the middle of these spindles, but unlike extrafusal muscle fibers, the myofibril contractile apparatus of spindle fibers are located only at both ends of spindle.
In modern clinical usage, the word bulbar (as in bulbar palsy) is retained for terms that relate to the medulla oblongata, particularly in reference to medical conditions. The word bulbar can refer to the nerves and tracts connected to the medulla such as the corticobulbar tract , and also by association to those muscles innervated , including ...
The pons (from Latin pons, "bridge") is part of the brainstem that in humans and other mammals, lies inferior to the midbrain, superior to the medulla oblongata and anterior to the cerebellum. The pons is also called the pons Varolii ("bridge of Varolius"), after the Italian anatomist and surgeon Costanzo Varolio (1543–75). [ 1 ]
Skeletal muscle cell types include: very large multinuclear muscle fiber cells; small endothelial cells that line the inside of capillary blood vessels; small fibro-adipogenic progenitor cells (FAPs) which are muscle-fiber-adjacent multipotent mesenchymal stem cells that under different conditions can differentiate into adipocytes, fibroblasts ...
Signal transmission from nerve to muscle at the motor end plate. The neuromuscular junction is the synapse that is formed between an alpha motor neuron (α-MN) and the skeletal muscle fiber. In order for a muscle to contract, an action potential is first propagated down a nerve until it reaches the axon terminal of the motor neuron.