| nervous colon syndrome | <syndrome> A common gastrointestinal disorder characterised by abdominal pain, bloating, mucous in stools, and irregular bowel habits with alternating diarrhoea and constipation, symptoms that tend to be chronic and wax and wane over the years. Although nervous colon syndrome can cause chronic recurrent discomfort, it appears to be an abnormal condition of gut contractions (motility) and does not lead to any serious organ problems. Diagnosis usually involves excluding other illnesses. Treatment is directed toward relief of symptoms and includes high fibre diet, exercise, relaxation techniques, avoidance of caffeine, milk products and sweeteners, and medications. Alternative names include irritable bowel syndrome, spastic colitis, and mucus colitis. (12 Dec 1998) |
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| nervous dyspepsia | Dyspepsia associated with nervousness, tension, or anxiety. Synonym: functional dyspepsia. (05 Mar 2000) |
| nervous indigestion | Indigestion caused by emotional upsets or stress. (05 Mar 2000) |
| nervous lobe | The bulbous part of the neurohypophysis attached to the hypothalamus by the infundibulum. It is composed of pituicytes, blood vessels, and terminals of nerve fibres from the supraoptic and paraventricular nuclei. Synonym: lobus nervosus, nervous lobe. (05 Mar 2000) |
| nervous lobe of hypophysis | The bulbous part of the neurohypophysis attached to the hypothalamus by the infundibulum. It is composed of pituicytes, blood vessels, and terminals of nerve fibres from the supraoptic and paraventricular nuclei. Synonym: lobus nervosus, nervous lobe. (05 Mar 2000) |
| nervous part of retina | nervous part of retina |
| nervous system | The entire integrated system of nerve tissue in the body: the brain, brainstem, spinal cord, nerves and ganglia. (16 Dec 1997) |
| nervous system abnormalities | Congenital structural abnormalities of the nervous system. (12 Dec 1998) |
| nervous system, autonomic | Part of the nervous system once thought functionally independent of the brain. The autonomic nervous system regulates key functions including the activity of the cardiac (heart) muscle, smooth muscles (e.g., of the gut), and glands. The autonomic nervous system has two divisions: (1) the sympathetic nervous system, which accelerates the heart rate, constricts blood vessels, and raises blood pressure; and (2) the parasympathetic nervous system, which slows the heart rate, increases intestinal and gland activity, and relaxes sphincter muscles. (12 Dec 1998) |
| nervous system, parasympathetic | A part of the nervous system that slows the heart rate, increases intestinal and gland activity, and relaxes sphincter muscles. The parasympathetic nervous system together with the sympathetic nervous system (that accelerates the heart rate, constricts blood vessels, and raises blood pressure) constitute the autonomic nervous system. (12 Dec 1998) |
| nervous system physiology | Functions and activities of the nervous system as a whole or with reference to the peripheral or the central nervous system. (12 Dec 1998) |
| nervous system, sympathetic | A part of the nervous system that accelerates the heart rate, constricts blood vessels, and raises blood pressure. The sympathetic nervous system together with the parasympathetic nervous system (that slows the heart rate, increases intestinal and gland activity, and relaxes sphincter muscles) constitute the autonomic nervous system. (12 Dec 1998) |
| nervous tissue | A highly differentiated tissue composed of nerve cells, nerve fibres, dendrites, and a supporting tissue (neuroglia). (05 Mar 2000) |
| nervous tunic of eyeball | Light sensitive layer of the eye. In vertebrates, looking from outside, there are four major cell layers: (i) the outer neural retina, which contains neurons (ganglion cells, amacrine cells, bipolar cells) as well as blood vessels, (ii) the photoreceptor layer, a single layer of rods and cones, (iii) the pigmented retinal epithelium (PRE or RPE), (iv) the choroid, composed of connective tissue, fibroblasts and including a well vascularised layer, the chorio capillaris, underlying the basal lamina of the PRE. Behind the choroid is the sclera, a thick organ capsule. In molluscs (especially cephalopods such as the squid) the retina has the light sensitive cells as the outer layer with the neural and supporting tissues below. See: retinal rods, retinal cones, rhodopsin. (18 Nov 1997) |
| sympathetic nervous system | <anatomy, physiology> One of the two divisions of the vertebrate autonomic nervous system (the other being the parasympathetic nervous system). The sympathetic preganglionic neurons have their cell bodies in the thoracic and lumbar regions of the spinal cord and connect to the paravertebral chain of sympathetic ganglia. Innervate heart and blood vessels, sweat glands, viscera and the adrenal medulla. most sympathetic neurons, but not all, use noradrenaline as a post ganglionic neurotransmitter. (19 Jan 1998) |