sympathetic nervous system


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Related to sympathetic nervous system: central nervous system

sympathetic

 [sim″pah-thet´ik]
1. pertaining to or caused by sympathy.
2. pertaining to the sympathetic nervous system.
sympathetic nervous system the thoracolumbar part of the autonomic nervous system, the preganglionic fibers of which arise from cell bodies in the thoracic and first three lumbar segments of the spinal cord; postganglionic fibers are distributed to the heart, smooth muscle, and glands of the entire body. (See also Plate 14.)
sympathetic stress reaction alarm reaction.

system

 [sis´tem]
1. a set or series of interconnected or interdependent parts or entities (objects, organs, or organisms) that act together in a common purpose or produce results impossible by action of one alone.
2. an organized set of principles or ideas. adj., adj systemat´ic, system´ic.

The parts of a system can be referred to as its elements or components; the environment of the system is defined as all of the factors that affect the system and are affected by it. A living system is capable of taking in matter, energy, and information from its environment (input), processing them in some way, and returning matter, energy, and information to its environment as output.

An open system is one in which there is an exchange of matter, energy, and information with the environment; in a closed system there is no such exchange. A living system cannot survive without this exchange, but in order to survive it must maintain pattern and organization in the midst of constant change. Control of self-regulation of an open system is achieved by dynamic interactions among its elements or components. The result of self-regulation is referred to as the steady state; that is, a state of equilibrium. homeostasis is an assemblage of organic regulations that act to maintain steady states of a living organism.

A system can be divided hierarchically into subsystems, which can be further subdivided into sub-subsystems and components. A system and its environment could be considered as a unified whole for purposes of study, or a subsystem could be studied as a system. For example, the collection of glands in the endocrine system can be thought of as a system, each endocrine gland could be viewed as a system, or even specific cells of a single gland could be studied as a system. It is also possible to think of the human body as a living system and the endocrine system as a subsystem. The division of a system into a subsystem and its environment is dependent on the perspective chosen by the person studying a particular phenomenon.
Systems, subsystems, and suprasystems. Within the environment there are suprasystems, such as human society, and systems within the suprasystem, such as the educational and industrial systems and the health care delivery system. Within the health care delivery system are subsystems, such as the patient, family members, the nurse, the physician, and allied health care professionals and paraprofessionals.
alimentary system digestive system.
apothecaries' system see apothecaries' system.
autonomic nervous system see autonomic nervous system.
avoirdupois system see avoirdupois system.
behavioral system in the behavioral system model of nursing, the patterned, repetitive, and purposeful behaviors of an individual.
cardiovascular system the heart and blood vessels, by which blood is pumped and circulated through the body; see also circulatory system.
CD system (cluster designation) a system for classifying cell-surface markers expressed by lymphocytes based on a computer analysis of monoclonal antibodies against hla antigens, with antibodies having similar specificity characteristics being grouped together and assigned a number (CD1, CD2, CD3, etc.); these CD numbers are also applied to the specific antigens recognized by the various groups of monoclonal antibodies. See also CD antigen.
centimeter-gram-second system (CGS) (cgs) a system of measurements in which the units are based on the centimeter as the unit of length, the gram as the unit of mass, and the second as the unit of time.
central nervous system see central nervous system.
centrencephalic system the neurons in the central core of the brainstem from the thalamus to the medulla oblongata, connecting the cerebral hemispheres.
circulatory system see circulatory system.
client system in the general systems framework and theory of goal attainment, the composite of physiological, psychological, sociocultural, and developmental variables that make up the total person.
colloid system (colloidal system) colloid (def. 3).
conduction system (conductive system (of heart)) the system of atypical cardiac muscle fibers, comprising the sinoatrial and atrioventricular nodes, internodal tracts, atrioventricular bundle, bundle branch, and terminal ramifications into the Purkinje network.
digestive system see digestive system.
Emergency Medical Services (EMS) system a comprehensive program designed to provide services to the patient in the prehospital setting. The system is activated when a call is made to the EMS operator, who then dispatches an ambulance to the patient. The patient receives critical interventions and is stabilized at the scene. A communication system allows the health care workers at the scene to contact a trauma center for information regarding further treatment and disposition of the patient, followed by transportation of the patient to the most appropriate facility for treatment.
endocrine system the system of ductless glands and other structures that produce internal secretions (hormones) that are released directly into the circulatory system, influencing metabolism and other body processes; see endocrine glands.
environmental control system environmental control unit.
expert system a set of computer programs designed to serve as an aid in decision making.
extrapyramidal system see extrapyramidal system.
gateway system a software interface between an online searcher and one or more search systems, facilitating the use of the system by searchers who are unfamiliar with it, or with online retrieval in general.
genitourinary system the organs concerned with production and excretion of urine, together with the reproductive organs. (See Plates.) Called also urogenital system.
haversian system a haversian canal and its concentrically arranged lamellae, constituting the basic unit of structure in compact bone (osteon).
Haversian system: Structures of compact and spongy bone with the central haversian canal surrounded by the lamellae. From Applegate, 2000.
health care system see health care system.
heterogeneous system a system or structure made up of mechanically separable parts, as an emulsion or suspension.
His-Purkinje system the intraventricular conduction system from the bundle of His to the distal Purkinje fibers, which carries the impulse to the ventricles.
Home Health Care Classification system see home health care classification system.
homogeneous system a system or structure made up of parts that cannot be mechanically separated, as a solution.
hypophyseoportal system (hypophysioportal system) (hypothalamo-hypophysial portal system) the venules connecting the hypothalamus with the sinusoidal capillaries of the anterior lobe of the pituitary gland; they carry releasing substances to the pituitary.
immune system see immune system.
interpersonal system in the general systems framework and theory of goal attainment, two or more individuals interacting in a given situation.
lay health system a system comprising an informal referral network and sources of treatment outside the formal biomedical sources of health care; it includes individual consultation and information-seeking through significant others and peers concerning health behaviors, symptoms, and evaluation of treatment before, during, and after consultation with health care professionals.
legal system in the omaha system, anything connected with law or its administration; it includes legal aid, attorney, courts, or Child Protective Services (CPS), and many other agencies and officials.
limbic system a system of brain structures common to the brains of all mammals, comprising the phylogenetically old cortex (archipallium and paleopallium) and its primarily related nuclei. It is associated with olfaction, autonomic functions, and certain aspects of emotion and behavior.
lymphatic system see lymphatic system.
lymphoid system the lymphoid tissue of the body, collectively; it consists of primary (or central) lymphoid tissues, the bone marrow, and thymus, and secondary (or peripheral) tissues, the lymph nodes, spleen, and gut-associated lymphoid tissue (tonsils, Peyer's patches).
lymphoreticular system the lymphoid and reticuloendothelial systems considered together; see also lymphoreticular disorders.
metric system see metric system.
mononuclear phagocyte system the group of highly phagocytic cells that have a common origin from stem cells of the bone marrow and develop circulating monocytes and tissue macrophages, which develop from monocytes that have migrated to connective tissue of the liver (kupffer's cells), lung, spleen, and lymph nodes. The term has been proposed to replace reticuloendothelial system, which includes some cells of different origin and does not include all macrophages.
nervous system see nervous system.
nursing system in the self-care model of nursing, all the actions and interactions of nurses and patients in nursing practice situations; nursing systems fall into three categories: wholly compensatory, partly compensatory, and supportive-educative.
Omaha system see omaha system.
oxygen delivery system a device that delivers oxygen through the upper airways to the lungs at concentrations above that of ambient air. There are two general types: the fixed performance or high flow type, which can supply all of the needs of a patient for inspired gas at a given fractional inspired oxygen; and the variable performance or low flow type, which cannot supply all of the patient's needs for oxygen and delivers fractional inspired oxygen that varies with ventilatory demand.
parasympathetic nervous system see parasympathetic nervous system.
peripheral nervous system the portion of the nervous system consisting of the nerves and ganglia outside the brain and spinal cord.
personal system in the general systems framework and theory of goal attainment, the unified self, a complex whole that is rational, conscious, and feeling and that sets goals and decides on the means of achieving them.
pituitary portal system hypothalamo-hypophysial portal system.
portal system an arrangement by which blood collected from one set of capillaries passes through a large vessel or vessels and another set of capillaries before returning to the systemic circulation, as in the pituitary gland (the hypothalamo-hypophysial portal system) or the liver (the hepatic portal circulation).
renin-angiotensin-aldosterone system see renin-angiotensin-aldosterone system.
respiratory system the group of specialized organs whose specific function is to provide for the transfer of oxygen from the air to the blood and of waste carbon dioxide from the blood to the air. The organs of the system include the nose, the pharynx, the larynx, the trachea, the bronchi, and the lungs. See also respiration and Plates 7 and 8.
reticular activating system see reticular activating system.
reticuloendothelial system see reticuloendothelial system.
safety system see safety system.
SI system see SI units.
skeletal system see skeletal system.
social system in the general systems framework and theory of goal attainment, an organized boundary system of social roles, behaviors, and practices developed to maintain balance for growth, development, and performance, which involves an exchange of energy and information between the person and the environment for regulation and control of stressors.
support system in the omaha system, the circle of friends, family, and associates that provide love, care, and need gratification; it may include church, school, workplace, or other groupings.
sympathetic nervous system see sympathetic nervous system.
Unified Medical Language system see unified medical language system.
Unified Nursing Language system see unified nursing language system.
unit dose system a method of delivery of patient medications directly to the patient care unit. Following review by a nurse, a copy of the physician's original order is sent to the pharmacy, where the pharmacist reviews it again. The pharmacist then fills the order and delivers the medication to the patient care unit, usually in a 24-hour supply. Each patient has an individual supply of medications prepared and labeled by the pharmacist.
urinary system the system formed in the body by the kidneys, ureters, urinary bladder, and urethra, the organs concerned in the production and excretion of urine.
urogenital system genitourinary system.
vascular system circulatory system.
vasomotor system the part of the nervous system that controls the caliber of the blood vessels.

sympathetic nervous system

n.
The part of the autonomic nervous system originating in the thoracic and lumbar regions of the spinal cord that in general inhibits or opposes the physiological effects of the parasympathetic nervous system, as in tending to reduce digestive secretions, speed up the heart, and contract blood vessels.

sympathetic nervous system

sym·pa·thet·ic ner·vous sys·tem

(SNS) (sim'pă-thet'ik nĕr'vŭs sis'tĕm)
1. In earlier usage, the entire autonomic nervous system.
2. The branch of the autonomic nervous system that supplies motor control to glands, smooth muscle, and cardiac tissue, specifically in response to perceived threat, danger, or to stress.
See also: autonomic division of nervous system
Compare: parasympathetic nervous system

sympathetic nervous system

One of the two divisions of the AUTONOMIC NERVOUS SYSTEM, the other being the PARASYMPATHETIC. The sympathetic system causes constriction of blood vessels in the skin and intestines and widening (dilatation) of blood vessels in the muscles. It increases the heart rate, dilates the pupils, widens the bronchial air tubes, relaxes the bladder and reduces the activity of the bowel.

sympathetic nervous system

see AUTONOMIC NERVOUS SYSTEM.

Sympathetic nervous system

The part of the autonomic nervous system that is concerned especially with preparing the body to react to situations of stress or emergency; it contains chiefly adrenergic fibers and tends to depress secretion, decrease the tone and contractility of smooth muscle, and increase heart rate.
Figure 1: Efferent nerve pathways from the brainstem and spinal cord. Shown on the right: somatic, to skeletal muscles. Shown on the left: autonomic. B brain stem, C cervical, T thoracic, L lumbar, S sacral segments of the spinal cord. (Red shaded regions are those with no autonomic outflow.)
Figure 2: The autonomic nervous system. Actions on the heart and on smooth muscle. Sympathetic actions on the left and parasympathetic actions on the right. Solid arrows: stimulation (contraction or secretion); broken arrows: inhibition.

sympathetic nervous system

one of the two divisions of the autonomic nervous system (ANS). Efferent fibres from nerve cells in the thoracolumbar segments of the spinal cord relay in a chain of sympathetic ganglia on each side of the spine in the thorax and abdomen; thence sympathetic postganglionic nerves reach all parts of the body except the central nervous system. They supply the heart, smooth muscle and many secretory glands. The main neurotransmitter is noradrenaline which has different actions depending on the type of receptors on the effector cells. This system is at all times active in the regulation of cardiac output, arterial blood pressure and regional blood flow (all contributing to adjustments in exercise), as well as priming the body for emergency 'fight or flight', when sympathetic nerves stimulate release of adrenaline from the adrenal medulla. The outflow from the spinal cord is influenced by inputs from the hypothalamus related to body temperature control, from the cardiovascular control centres in the brain stem, and by afferents from the alimentary tract and other organs. Dual sympathetic and parasympathetic innervation provides for synergistic interaction, although the effects are often opposite; most vascular smooth muscle is an exception, having only a sympathetic nerve supply. See Figure 1, Figure 2.

sympathetic nervous system

; SNS cell bodies of motor nerves located in intermediate columns of spinal cord between T1 and L2 vertebrae; synapse with paravertebral sympathetic ganglia (forming two chains to either side of spinal cord); all preganglionic and most postganglionic SNS fibres use adrenaline or nor- adrenaline as neurotransmitter; note: SNS input to sweat glands is cholinergic (i.e. uses acetylcholine as neurotransmitter)

sym·pa·thet·ic ner·vous sys·tem

(sim'pă-thet'ik nĕr'vŭs sis'tĕm)
1. In earlier usage, the entire autonomic nervous system.
2. The branch of the autonomic nervous system that supplies motor control to glands, smooth muscle, and cardiac tissue, specifically in response to perceived threat, danger, or to stress.

sympathetic

pertaining to the sympathetic nervous system.

acute sympathetic blockade
trauma to the cervical spinal cord may be associated with bradycardia and hypotension.
sympathetic chain
the sympathetic trunk whose ganglia suggest a chain of beads.
sympathetic cholinergic vasodilator fibers
a system of efferent dilator nerves distributed only to skeletal muscles; the existence of the system has been verified only in cats and dogs; in other species where it is not present vasodilation is achieved only by relaxation of vasoconstrictor tone.
sympathetic nerves
1. see sympathetic trunk (below).
2. any nerve of the sympathetic nervous system.
sympathetic nervous system
the part of the autonomic nervous system whose preganglionic fibers arise from cell bodies in the thoracic and lumbar segments of the spinal cord; postganglionic fibers are distributed to the heart, smooth muscle, and glands of the entire body.
sympathetic outflow
the preganglionic fibers from the nerve cells in the thoracolumbar cord.
sympathetic regurgitation
see neurotic regurgitation.
sympathetic trunk
two long ganglionated nerve strands, one on each side of the vertebral column, extending from the base of the skull to the coccyx.
sympathetic trunk ganglia
ganglia situated segmentally along the paired sympathetic trunks beside the vertebral bodies.
References in periodicals archive ?
Will an understanding of the intricacies of the sympathetic nervous system and "event-related negativity" make him a more viable gunfighter in this circumstance?
Progesterone treatment was linked with increased leukemias and sympathetic nervous system cancers in the children of treated mothers.
The sympathetic nervous system is in touch with every organ and muscle, ready to mobilize the body's fight-or-flight response to stress.
turns out that the dominant influences on HR control are the parasympathetic and sympathetic nervous systems (Figure 2).
Causalgia and reflex sympathetic dystrophy: does the sympathetic nervous system contribute to the generation of pain?
When a patient has CHF, the sympathetic nervous system trigers the release of epinephrine.
According to the present study, the cholinergic activity of the sympathetic nervous system against stressor factor was not different in patients with FM and controls.
This in turn activates the sympathetic nervous system, resulting in elevated blood pressure and tachycardia.
MetS is characterized by obesity, type 2 diabetes, hypertension, and dyslipidemia, and is associated with increased activity of the sympathetic nervous system.
During an orgasm the sympathetic nervous system goes into overdrive.
It occurs when cortisol and sympathetic nervous system are in sync but functioning at low levels.
Neuroblastoma, a cancer of the sympathetic nervous system, is the most common tumor in the first year of life.