A reflexes

Theorem 1.10. A closed convex set of a reflexive Banach space is weakly closed. 

Theorem 1.11. Let V be a reflexive Banach space, and K c V be a closed convex set. Assume that J V R is a coercive and weakly lower semicontinuous functional. Then the problem... 

Theorem 1.14. Let V be a reflexive separable Banach space. Assume that an operator A E —> E possesses the following properties ... 

Let K cV he a. convex closed subset of a reflexive Banach space V, I he a duality mapping, and P be a projection operator of V onto K. We are in a position to give a definition of a penalty operator. An operator (5 V V is called a penalty operator connected with the set K if the following conditions are fulfilled. Firstly, / is a monotonous bounded semicontinuous operator. Secondly, a kernel of / coincides with K, i.e. 

Let K he a closed convex subset in a reflexive Banach space V let an operator A act from V into V and let f G V he given. Consider the variational inequality... 

The cardiovascular adverse effects associated with quinidine therapy are hypotension and tachycardia, both of which are related to its a-adrenoceptor blocking actions. The tachycardia may be a reflex adjustment to the fall in blood pressure or may also be a direct action of the dmg on sympathetic nerve terminals leading to an increased release of NE. Quinidine also produces ringing in the ears (cinchonism) (1,2). 

Phenylephrine. Phenylephrine hydrochloride is an a -adrenoceptor agonist. Phenylephrine produces powerful vasoconstrictor and hypertensive responses. This results in baroreceptor activation of a reflex bradycardia and thus is useful in the treatment of supraventricular tachyarrhythmias. Unlike epinephrine [51-43-4] the actions of which are relatively transient, phenylephrine responses are more sustained (20 min after iv dosing and 50 min after subcutaneous dosing) (86). 

Re-examining the four conditions, one notices that the congruence of graphs as defined here establishes a reflexive, symmetric, and transitive relation between graphs. Observe that (IV) does not involve an arbitrary set but a group of permutations. 

Emesis is the forcefiil involuntary expulsion of the stomach contents through the mouth. It is a reflex response that may be initiated by a number of stimuli. 

We proposed the term psychoneurogenic for the mechanism of these reactions, since the direct action on the nerve might elicit a reflex cascade via the CNS and then lead to the above-mentioned symptoms. Why these reactions only occur in certain individuals, maybe due to pharmacogenomics and specific hyperexcitability of peripheral nerves, remains open for speculation. There is a high degree of psychosomatic involvement in such reactions. 

The fluid and protein shift into the abdomen (called third-spacing) may be so dramatic that circulating blood volume is decreased, which causes decreased cardiac output and hypovolemic shock. Accompanying fever, vomiting, or diarrhea may worsen the fluid imbalance. A reflex sympathetic response, manifested by sweating, tachycardia, and vasoconstriction, may be evident. With an inflamed peritoneum, bacteria and endotoxins are absorbed easily into the bloodstream (translocation), and this may result in septic shock. Other foreign substances present in the peritoneal cavity potentiate peritonitis, notably feces, dead tissues, barium, mucus, bile, and blood. 

Vomiting A reflexive rapid and forceful oral expulsion of upper gastrointestinal contents due to powerful and sustained contractions in the abdominal and thoracic musculature. 

A reflex occurs when a particular stimulus always elicits a particular response. This response is automatic and involuntary in other words, it occurs without conscious effort. Therefore, reflexes are specific, predictable, and, furthermore, often purposeful. For example, the withdrawal reflex causes a body part to be pulled away from a painful stimulus so that tissue injury is avoided. Spinal reflexes require no input from the brain because they are elicited entirely at the level of the spinal cord. However, while the reflex is underway, nervous impulses are also transmitted to the brain for further processing. In fact, input from the brain may modulate a reflex or alter the response to a stimulus through conscious effort. 

A reflex response requires an intact neural pathway between the stimulated area and the responding muscle. This pathway is referred to as a reflex arc and includes the following components (see Figure 7.3) ... 

Figure 7.3 Components of a reflex arc. As illustrated by the components of the reflex arc, reflexes may be processed entirely at the level of the spinal cord with no need for input from the brain. A monosynaptic reflex has a single synapse between afferent and efferent neurons a polysynaptic reflex has two or more synapses between these neurons. In this case, intemeurons lie between the sensory and motor neurons. The more intemeurons involved, the more complex the response is.

A reflex is initiated by stimulation of a sensory receptor located at the peripheral ending of an afferent or first-order sensory neuron. This afferent neuron transmits impulses to the spinal cord. Within the gray matter of the spinal cord, the afferent neuron synapses with other neurons. As such, the spinal cord serves as an integrating center for the sensory input. The afferent neuron must ultimately synapse with an efferent or motor neuron. When the afferent neuron synapses directly with the motor neuron, it forms a monosynaptic reflex. An example of this type of reflex is the stretch reflex. When the afferent neuron synapses with an intemeuron that then synapses with the motor neuron, it forms a polysynaptic reflex, e.g., the withdrawal reflex. Most reflexes are polysynaptic. The motor neuron then exits the spinal cord to innervate an effector tissue, which carries out the reflex response. 

Baroreceptors are sensitive to changes in MAP. As VR, CO, and MAP decrease, baroreceptor excitation is diminished. Consequently, the frequency of nerve impulses transmitted from these receptors to the vasomotor center in the brainstem is reduced. This elicits a reflex that will increase HR, increase contractility of the heart, and cause vasoconstriction of arterioles and veins. The increase in CO and TPR effectively increases MAP and therefore cerebral blood flow. Constriction of the veins assists in forcing blood toward the heart and enhances venous return. Skeletal muscle activity associated with simply walking decreases venous pressure in the lower extremities significantly. Contraction of the skeletal muscles in the legs compresses the veins and blood is forced toward the heart. 

Pain receptors also influence the medullary respiratory center. Pain may cause a reflex increase in ventilation in the form of a "gasp." Somatic pain typically causes hyperpnea and visceral pain typically causes apnea, or decreased ventilation. 

Food is stored in the body of the stomach, which may expand to hold as much as 11 of chyme. As food enters the stomach, it undergoes a reflex relaxation referred to as receptive relaxation. It enhances the ability of the stomach to accommodate an increase in volume with only a small increase in stomach pressure. The fundus does not typically store food because it is located above the esophageal opening into the stomach. Instead, it usually contains a pocket of gas. 

Monosynaptic reflex A reflex arc (pathway) with a single synapse. 

The answer is a. (Hardman, pp 762-764.) Experimentally, nitrates dilate coronary vessels. This occurs in normal subjects, resulting in an overall increase in coronary blood flow. In arteriosclerotic coronaries, the ability to dilate is lost, and the ischemic area may actually have less blood flow under the influence of nitrates. Improvement in the ischemic conditions is the result of decreased myocardial oxygen demand because of a reduction of preload and afterload. Nitrates dilate both arteries and veins and thereby reduce the work of the heart. Should systemic blood pressure fall, a reflex tachycardia will occur. In pure coronary spasm, such as Prinzmetal s angina, the effect of increased coronary blood flow is relevant, while in severe left ventricular hypertrophy with minimal obstruction, the effect on preload and afterload becomes important. 

The apneic episode is terminated by a reflex action in response to the fall in blood 02 saturation that causes a brief arousal during which breathing resumes. 

Berge, O. G. (1982) Effects of 5-HT receptor agonists and antagonists on a reflex response to radiant heat in normal and spinally transected rats. Pain, 13 253-266. 

Java also supports such a reflexive layer Classes, interfaces, methods, and instance variables can all be manipulated as runtime entities, although in a more restricted form than in Smalltalk. The language still needs work in this area. 

In open systems design, it is important that an object be able to engage in a dialog about its capabilities just as, for example, fax machines begin by agreeing on a commonly understood transmission protocol. This comes naturally to a reflexive language others must have the facility stuck on. C++ has recently acquired a limited form of such a feature with runtime type identification (RTTI). 

Phase 1 During phase 1, the increased thoracoabdominal pressure transiently increases venous return, thereby raising BP and reflexly lowering heart rate. Phase 2 During phase 2, the sustained rise in intrathoracic pressure reduces venous return VR and so BP falls until a compensatory tachycardia restores it. Phase 3 The release of pressure in phase 3 creates a large empty venous reservoir, causing BP to fall. Show that the heart rate remains elevated. Phase 4 The last phase shows how the raised heart rate then initially leads to a raised BP as venous return is restored. This is followed by a reflex bradycardia before both parameters eventually return to normal. 

To summarize there are two learning paradigms in the context of a reflex action controlled by a single ganglion in an experimental animal in which electrical measurements of nerve action are relatively easy. This experimental system permitted Kandel to map the neural circuit responsible for the gill-withdrawal reflex. The neural... 

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