Proprioceptive Reflex Control of Muscle Tension
When muscle spindles respond to stretching or to a change in the length of a given muscle, there is increased activity in the Ia afferent fibers, which then directly stimulates…
Muscle and Joint Receptors
JOINT RECEPTORS Four types of receptors have been described in the joint capsule and ligaments. Golgitype endings are located in ligaments but not in the capsule, and are innervated by…
Pacinian Corpuscle
The pacinian corpuscle consists of the unmyelinated terminal part of an afferent nerve fiber that is surrounded by concentric lamellae formed by the membranes of numerous supporting cells. The axon…
Cutaneous Receptors
Three types of receptors are common to glabrous and hairy skin: pacinian (lamellated) corpuscles, Merkel disks, and free nerve endings. The pacinian corpuscle has been identified as a quickly adapting…
Visceral Efferent Endings
Autonomic neuromuscular endings control such diverse functions as heart rate, intestinal and urogenital activity, pupillary size, and blood pressure. The mor phologic features of this type of ending are shown…
Conduction Velocity
In a myelinated nerve fiber, successive 1- to 2-mm segments of axon, called internodes, are enveloped by multiple layers of Schwann cell membrane. Between these segments are short lengths of…
Neurophysiology and Peripheral Nerve Demyelination
On neurophysiologic testing with motor nerve conduction studies (NCS), the pattern of changes in the recorded responses differs when focal neurapraxia occurs to the same degree and at the same…
Ion Channel Mechanics and Action Potential Generation
At rest, the resting membrane potential, or the absolute difference in electrical potential between the inside and the outside of the inactive neuron, results predominantly from the membrane permeability to…
Impulse Propagation
Action Potential Propagation. Three stages illustrate the propagation of an action potential past a point on an axon at which microelectrodes have been positioned to record intracellular and extracellular potentials,…
Resting Membrane Potential
The transmembrane ion concentrations at rest is dependent upon the passive diffusion of ions from the site of higher concentration to the site of lower concentration through ion channels, as…
