Central nervous system connectivity

The parasympathetic nervous system is capable of maintaining gastrointestinal motility, etc., even when connections to the central nervous system have been... 

Deletions in the elastin gene (located at 7qll.23) have been found in approximately 90% of subjects with Williams syndrome, a developmental disorder affecting connective tissue and the central nervous system. The mutations, by affecting synthesis of elastin, probably play a causative role in the supravalvular aortic stenosis often found in this condition. A number of skin diseases (eg, scleroderma) are associated with accumulation of elastin. Fragmentation or, alternatively, a decrease of elastin is found in conditions such as pulmonary emphysema, cutis laxa, and aging of the skin. 

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. 

BZ is usually disseminated as an aerosol with the primary route of entry into the body through the respiratory system the secondary route is through the digestive tract. BZ blocks the action of acetylcholine in both the peripheral and central nervous systems. As such, it lessens the degree and extent of the transmission of impulses from one nerve fiber to another through their connecting synaptic junctions. It stimulates the action of noradrenaline (norepinephrine) in the brain, much as do amphetamines and cocaine. Thus, it may induce vivid hallucinations as it sedates the victim. Toxic delirium is very common. 

Ganglia Clusters of multipolar neurons surrounded by a capsule of loosely organized connective tissue located outside the central nervous system. [NIH]... 

The central nervous system includes the brain and the spinal cord. We shall refer to it as the CNS. The peripheral nervous system, PNS, is composed of nerves, bundles of individual cells called neurons, which connect the CNS to the rest of the body. If we make a very rough analogy to a bicycle wheel, then the CNS is the hub and the PNS is the spokes. When the bike tire hits the road, force is generated at the hub and is transmitted by the spokes. 

Figure 14.4 Different types of glial cells. Astrocytes connect capillaries and neurones. Fibrous astrocytes, with less branching and more filamentous processes, occur mainly in white matter while protoplasmic astrocytes are located principally in the grey matter. Oligodendrocytes form the myelin sheath by wrapping themselves around axons. The connection between the myelin sheath and the oligodendrocyte is permanent and provides material for the myelin sheath. Microgliocytes (microglia) are the phagocytes of the nervous system. The ciliated ependymal cells line the cavities of the central nervous system.

A large multicentric cohort study of European vinyl chloride workers revealed a nearly threefold increase in liver cancer based on 24 observed deaths vs. 8.4 expected. The excess was clearly related to time since first exposure, duration of employment, and estimated ranked and quantitative exposures. A cohort study of 10,173 US men who had worked at least 1 year in jobs involving exposure to vinyl chloride confirmed a significant mortality excess in angiosarcoma (15 deaths), cancer of the liver and bilary tract [standardized mortality ratio (SMR) = 641], and cancer of central nervous system (SMR = 180). ° A recent follow-up of this cohort found that excess mortality risk from cancer of the liver and biliary tract, largely due to angiosarcoma, continued risk of mortality from brain cancer had attenuated and excess of deaths from cancer of connective and soft tissue appeared for the first time but was based on few cancers of assorted histology."... 

The muscarinic cholinergic receptor is competitively blocked by hyoscine and hyoscyamine. Both of these alkaloids are more active than atropine. The applications of these alkaloids for clinical purposes are connected with the induction of general anaesthesia. Clinical consideration should be paid to the fact that these alkaloids also affect the brain and thereby the central nervous system. Atropine crosses the blood-brain barrier. Hyoscine and hyoscyamine depress the motor areas of the cerebral cortex. 

How are the 10 neurons in the central nervous system arranged to process information How do they communicate through their 10 -10" connections with each other Most importantly for psychiatrists how can environmental influences, such as a pharmacological intervention or psychotherapy, influence the way in which the brain processes information ... 

Classically, the central nervous system has been envisioned as a series of hard-wired synaptic connections between neurons, not unlike millions of telephone wires within thousands upon thousands of cables (Fig. 1—4). This idea has been referred to as the anatomically addressed nervous system. The anatomically addressed brain is thus a complex wiring diagram, ferrying electrical impulses to wherever the wire is plugged in (i.e., at a synapse). There are an estimated 100 billion neurons, which make over 100 trillion synapses, in a single human brain. 

Other evidence which has been adduced to support the significance of neurogenic factors in renal hypertension is the observation that the arterial pressures of normal and renal hypertensive dogs and rabbits were reduced to essentially the same level after complete destruction of the central nervous system (18,19). However, interpretation of the results obtained with this drastic procedure is difficult. Other workers have observed a sharp fall in pressure when the spinal cord was destroyed below C5 (the level of the fifth cervical vertebra) in renal hypertensive dogs, but the pressures returned to hypertensive levels as the acute effects of the operation wore off (32). Other experiments involving elimination of the central connections of the sympathetics by cervical cord section in the region of C7... 

A common concurrent manifestation of FAS include central nervous system defects. These include irregular arrangement of neurons and connective tissue. Mental retardation may also be present and associated with learning disabilities as well as difficulties in controlling body coordination. 

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