Name the detected change and coordinating route, follow the signal through CNS, autonomic nerve or hormone and state the specific effector response.
Due to the expansive nature of the vagus nerve, it has been described as an ideal "early warning system" for foreign invaders as well as for monitoring the body's recovery. Up to 80% of vagal fibers are sensory and innervate nearly all major organs. Parasympathetic ganglia have been found to express receptors for interleukin-1, a key cytokine in the inflammatory immune response. This, in turn, activates the hypothalamic-pituitary-adrenal axis and SNS, leading to the release of glucocorticoids and NE, respectively.
Postural Orthostatic Tachycardia Syndrome (POTS): A Diagnostic Dilemma
POTS is defined as orthostatic intolerance associated with tachycardia exceeding 120 beats per minute or an increase in the heart rate of 30 beats per minute from baseline within 10 minutes of changing the posture from a lying to standing position, in the absence of long-term chronic diseases and medications that affect the autonomic or vascular tone. There is no drop in blood pressure; it may even rise in the upright posture. Patients experience symptoms such as headache, nausea, tremors, sweating, palpitation and near syncope. Symptoms always occur in the upright posture and disappear on lying down. POTS was first described in 1940, and it is considered one of the common conditions in young females. It occurs most commonly between the ages of 12 and 50 years with a male to female ratio of one: five. The underlying pathophysiological mechanism is assumed to be failure of peripheral vascular resistance to increase sufficiently in response to orthostatic stress, and, consequently, venous pooling occurs in the legs resulting in decreased venous return to the heart. This is compensated for by an increase in heart rate and inotropy.
Box 1
Enteric Nervous System