Efferent nerve

Nonadrenergic noncholinergic inhibitory responses to autonomic nerve stimulation are mainly mediated through NO synthesized by nNOS NO plays a crucial role as a neurotransmitter from the peripheral efferent nerves, thus being called nitrergic. This provides a... 

The cell bodies of visceral motor neurons are found in the lateral horn. The axons of these neurons form efferent nerve fibers of the autonomic nervous system (ANS). The ANS innervates cardiac muscle, smooth muscle and glands (see Chapter 9). The axons of these neurons exit the spinal cord by way of the ventral root. 

Hair cells are neuroepithelial cells their large basolat-eral surface includes synaptic contacts with afferent and efferent nerve fibers, while the mechanically sensitive hair bundle is located on their apical surface. The hair bundle is an ensemble of 30-300 actin-filled stereocilia and a single axonemal kinocilium (Fig. 51-2). The kinocilium,... 

There are three types of nenron. Sensory (or afferent) nenrons, as their name implies, carry sense information abont the body motor (or efferent) nerve cells carry instrnctions from the CNS, in the form of nervons impnlses, to the mnscles, organs, and glands of the body. The associated neurons, which have several other names, are involved in detecting impnlses from sensory nenrons and passing them to motor nenrons. 

The parasympathetic cholinergic pathway emanating from the vagus nerve exerts the main neuronal control in human airways. The cholinergic efferent nerves synapse in ganglia within the airways, and from there,... 

Toda N, Herman AG Gastrointestinal function regulation by nitrergic efferent nerves. Pharmacol Rev 2005 57 315. [PMID 16109838]... 

The anaesthetic is injected into the subarachnoid space via a lumbar puncture between vertebrae L2 and L3 or L3 or L4. This places the anaesthetic in the cerebro-spinal fluid. Efferent nerves (motor and sympathetic) and afferent fibres (sensory) are affected by the local anaesthetic. This method carries a risk of damage to the spinal cord. 

DIVISIONS OF THE PERIPHERAL AUTONOMIC SYSTEM EFFERENT NERVES... 

Afferent nerves carry information from the eyes to the PVA and on to the visual association cortex, whereas efferent nerves send action potentials in the opposite direction. Stored visual memories in the visual associate cortex travel backward to the PVA, evoking a pattern of activity in the topographically mapped areas to produce a perceived image. Because this image originated from memory, it is a perceived mental picture, not a sensation. 

The peripheral nervous system (those nerves outside the central nervous system or CNS) of vertebrates is made up of both sensory (afferent) and motor (efferent) nerves (figure). Each of these includes a bundle of nerve cells that connect to different sensors and actuators in the body. Motor nerves can be either somatic (mostly voluntary) or autonomic (mostly involuntary). 

Stimulation may be done with the same electrode designs either transcutaneous right above the bundle of interest, or by needles. Muscles, for example, in the hand are stimulated by stimulating efferent nerves in the arm. EMG electrodes can pick up the result of this stimulation, for instance for nerve velocity determination. It can also be picked up by neurographic electrodes, but the signal is much smaller and must therefore be averaged with multiple stimuli. However, the method is more interesting because there is more information in the response waveforms. 

Afferent and efferent nerves are often in the same nerve bundle. A stimulation signal can therefore go both ways, and from the central nervous system (CNS) side signals can be delayed and returned back to the signal origin. 

Figure 10.31 shows the minimum stimulus current to an efferent nerve fiber as a function of pulse duration for obtaining a certain muscle response. The coupling (synapses) between the nerve axon end plates and the muscle cells is an important part of this signal transmission line. It is not possible to lower the current under a certain minimum level, the rheobase value. The pulse length with current amplitude two x rheobase value is called the chronaxie. 

Figure 10.31 Minimum stimulus current to an efferent nerve fiber bundle for obtaining a certain muscle response, as a function of pulse duration.

The airways are supplied by three basically different types of primary efferent nerve endings ... 

The carotid bodies have been known since 1743. They are small, pinkish neurovascular structures 1-2 mm in diameter they are located at the posterior aspect of the common carotid, where it divides into the internal and external carotids. Carotid bodies are vascularized by the occipital branch of the external carotid. The efferent nerve fibers of the carotid body converge into the carotid branch of the ninth cranial nerve, or glossopharyngeal nerve. 

Assuming that the epithelioid cells are the actual chemoreceptors, the histological arrangement assures maximum efficiency by securing an abundant blood supply through the sinuses and a concentrated array of afferent and efferent nerve endings. 

Figure 5.5. Diagrammatic representation of the connections between a-and y-motoneurons and muscle. The muscle spindles receive constant stimulation from the y-efferent nerves leading to contraction of their intrafusal fibres. Impulses are then dischargedfrom the spindles through the ot-afferent nerves, resulting in the discharge of impulses through the a-ejferent pathway and leading to contraction of the extrafusal fibres of the skeletal muscle...

Afferent nerve. A nerve carrying impulses toward the central nervous system (CNS). Efferent nerve. A nerve canying impulses from the CNS. 

Sympathetic and parasympathetic efferent nerves innervate the capacitance vessels and regulate vascular tone. Both play an important role in the control of... 

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