Nerve Control

On the other hand, afferent nitrergic nerves control some sensory information processing, such as pain and reflex. 

Enteric nerves control intestinal smooth muscle action and are connected to the brain by the autonomic nervous system. IBS is thought to result from dysregulation of this brain-gut axis. The enteric nervous system is composed of two gan-glionated plexuses that control gut innervation the submucous plexus (Meissner s plexus) and the myenteric plexus (Auerbach s plexus). The enteric nervous system and the central nervous system (CNS) are interconnected and interdependent. A number of neurochemicals mediate their function, including serotonin (5-hydroxytryptamine or 5-HT), acetylcholine, substance P, and nitric oxide, among others. 

Neurons in different regions of the gray matter can connect with each other, forming spinal reflex arcs between sensory nerves bringing together noxious stimuli and motor nerves controlling avoidance responses. The behavioral consequences of such spinal reflexes are familiar in everyday life the eye blinks as an object approaches, the hand is withdrawn from a hot plate, both without conscious control. 

Most of the luminescent systems mentioned appear to be. under some nerve control. Normally, a luminous flash is observed after mechanical or electrical stimulation of most of the aforementioned species. A number of these also exhibit a diurnal rhythm of luminescence. 

Figure 4.3. Representative set of spleen and hepatic sinus volumes, measured in vivo with MRI, during an 8 min simulated dive in a young elephant seal. The MRI images indicated that spleen emptying requires only two or so minutes. The contents are initially tranferred into the hepatic sinus and then RBCs are metered out into the blood more slowly, apparently through phrenic nerve control of the caval sphincter. Data from Thornton (2000).

With cobra venom, the major effect is due to a toxin that acts on the nervous system. This neurotoxin is a small molecule, which can distribute throughout the body rapidly It acts like curare, paralysing the centre in the brain that controls breathing. By acting at the point where nerves control muscles it blocks the transmission of nerve impulses and causes muscle weakness and again affects breathing. The eyelids droop and speech becomes incoordinated. 

Neuromuscular junction—The point at which a nerve ending intersects with a muscle cell. The nerve controls muscle movements. Neurotransmitter—A chemical that is released from nerve ends to achieve a physiologic response, whether muscle contraction, speech, reflex action, or whatever. 

Spinal nerve— A nerve fiber that rises from the spinal cord instead of directly from the brain. Spinal nerves control muscle movement without conscious thought from an individual. 

Central nervous system The system of neurons comprising the brain and the spinal cord. It serves as the body s major nerve-control system, directing and regulating all parts of the body to receive stimuli from external and internal environments and interpreting those stimuli that cause the body to react. 

Heart rate variability has been used as an indicator of vagal nerve control. Heart rate variability appears to give the cardiovascular controller precise information for optimum blood pressure control (Figure 6.14.7). 

In living tissue, important communication control is implemented by hormones and nerves. Hormones are slow broadcasting information carriers nerves are quick prewired point-to-point information carriers. Some cells are not excitable, such as adipose, connective tissue, and blood. They are passive, not under nerve control, and only weakly polarized. However, nerve, muscle, and gland cells are polarized and excitable within a 1/1000 s, such cells may react on trigger signals. The excitation of a cell is accompanied by an action potential. The action potential is the basic bioelectric event and signal source in the body. 

EDA is divided into tonic (level) and phasic (response) phenomena. Both tonic levels (skin conductance level, skin potential level) and responses (SCR, skin potential response) are of interest working with EDA. They are generated under autonomous nerve control of the active organs of the skin, in particular the sweat glands. 

Scientists developed neuroprostheses that restore urinary bladder function by stimulating the spinal cord or nerves controlling the lower urinary tract. 

Some ketone solvents (not acetone or metlyletltyl ketone) can produce disease of the peripheral nerves in the body leading to shakes, twitching, or loss of nerve control or muscle action. Vibration, particularly from hand tools, can also produce this effect in the hand and lower arm. 

Mg2+ Cation outside the cell 50% of magnesium in the body in bone structure Essential for certain enzymes, muscles, nerve control Widely distributed (part of chlorophyll of all green plants), nuts, whole grains Disorientation, hypertension, tremors, slow pulse Drowsiness... 

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