Central nervous system

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central

 [sen´tral]
pertaining to a center; located at the midpoint.
central cord syndrome injury to the central portion of the cervical spinal cord resulting in disproportionately more weakness or paralysis in the upper extremities than in the lower; pathological change is caused by hemorrhage or edema.
 Central cord syndrome. From Ignatavicius and Workman, 2002.
central fever sustained fever resulting from damage to the thermoregulatory centers of the hypothalamus.
central nervous system the portion of the nervous system consisting of the brain and spinal cord. See also Plate 14.
central venous catheterization insertion of an indwelling catheter into a central vein for administering fluid and medications and for measuring central venous pressure. The most common sites of insertion are the jugular and subclavian veins; however, such large peripheral veins as the saphenous and femoral veins can be used in an emergency even though they offer some disadvantages. The procedure is performed under sterile conditions and placement of the catheter is verified by x-rays before fluids are administered or central venous pressure measurements are made.

Selection of a large central vein in preference to a smaller peripheral vein for the administration of therapeutic agents is based on the nature and amount of fluid to be injected. Central veins are able to accommodate large amounts of fluid when shock or hemorrhage demands rapid replacement. The larger veins are less susceptible to irritation from caustic drugs and from hypertonic nutrient solutions administered during parenteral nutrition.
Patient Care. Patients who have central venous lines are subject to a variety of complications. Air embolism is most likely to occur at the time a newly inserted catheter is connected to the intravenous tubing. Introduction of air into the system can be avoided by having the patient hold his breath and contract the abdominal muscles while the catheter and tubing are being connected. This maneuver increases intrathoracic pressure; if the patient is not able to cooperate, the connection should be made at the end of exhalation.

Sepsis is a potential complication of any intravenous therapy. It is especially dangerous for patients with central venous lines because they are seriously ill and less able to ward off infections. Careful cleansing of the insertion site, sterile technique during insertion, periodic changing of tubing and catheter, and firmly anchoring the catheter to prevent movement and irritation are all essential for the prevention of sepsis.

Formation of a clot at the tip of the catheter is indicated if the rate of flow of intravenous fluids decreases measurably or if there is no fluctuation of fluid in the fluid column. Preventive measures include maintaining a constant flow of intravenous fluids by IV pump or controller, periodic flushing of the catheter, heparin as prescribed, and looping and securing the catheter carefully to avoid kinks that impede the flow of fluids. Cardiac arrhythmias can occur if the tip of the catheter comes into contact with the atrial or ventricular wall. Changing the patient's position may eliminate the problem, but if ectopic rhythm persists, additional interventions are warranted.
central venous pressure (CVP) the pressure of blood in the right atrium. Measurement of central venous pressure is made possible by the insertion of a catheter through the median cubital vein to the superior vena cava. The distal end of the catheter is attached to a manometer (or transducer and monitor) on which can be read the amount of pressure being exerted by the blood inside the right atrium or the vena cava. The manometer is positioned at the bedside so that the zero point is at the level of the right atrium. Each time the patient's position is changed the zero point on the manometer must be reset. For a multilumen catheter the distal port is used to measure central venous pressure; for a pulmonary artery catheter the proximal port is used.

An arterial line can also be used to monitor the central venous pressure. The waveform for a tracing of the pressure reflects contraction of the right atrium and the concurrent effect of the ventricles and surrounding major vessels. It consists of a, c, and v ascending (or positive) waves and x and y descending (or negative) waves. Since systolic atrial pressure (a) and diastolic (v) pressure are almost the same, the reading is taken as an average or mean of the two.

The normal range for CVP is 0 to 5 mm H2O. A reading of 15 to 20 mm usually indicates inability of the right atrium to accommodate the current blood volume. However, the trend of response to rapid administration of fluid is more significant than the specific level of pressure. Normally the right heart can circulate additional fluids without an increase in central venous pressure. If the pressure is elevated in response to rapid administration of a small amount of fluid, there is indication that the patient is hypervolemic in relation to the pumping action of the right heart. Thus, CVP is used as a guide to the safe administration of replacement fluids intravenously, particularly in patients who are subject to pulmonary edema. Central venous pressure indirectly indicates the efficiency of the heart's pumping action; however, pulmonary artery pressure is more accurate for this purpose.

A high venous pressure may indicate congestive heart failure, hypervolemia, cardiac tamponade in which the heart is unable to fill, or vasoconstriction, which affects the heart's ability to empty its chambers. Conversely, a low venous pressure indicates hypovolemia and possibly a need to increase fluid intake.

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.

cen·tral ner·vous sys·tem (CNS),

[TA]
the brain and the spinal cord.

central nervous system

n. Abbr. CNS
The portion of the vertebrate nervous system consisting of the brain and spinal cord.

central nervous system (CNS)

Etymology: Gk, kentron + L, nervus, nerve; Gk, systema
one of the two main divisions of the nervous system, consisting of the brain and the spinal cord. The central nervous system processes information to and from the peripheral nervous system and is the main network of coordination and control for the entire body. The brain controls many functions and sensations, such as sleep, sexual activity, muscular movement, hunger, thirst, memory, and emotions. The spinal cord extends various types of nerve fibers from the brain and acts as a switching and relay terminal for the peripheral nervous system. The 12 pairs of cranial nerves emerge directly from the brain. Sensory nerves and motor nerves of the peripheral system leave the spinal cord separately between the vertebrae but unite to form 31 pairs of spinal nerves containing sensory fibers and motor fibers. More than 10 billion neurons constitute but one tenth of the brain cells; the other cells consist of neuroglia that support the neurons. The neurons and the neuroglia form the soft, jellylike substance of the brain, which is supported and protected by the skull. The brain and the spinal cord are composed of gray matter and white matter. The gray matter primarily contains nerve cells and associated processes; the white matter consists predominantly of bundles of myelinated nerve fibers. Compare peripheral nervous system. See also brain, spinal cord.
enlarge picture
Central nervous system

cen·tral ner·vous sys·tem

(CNS) (sen'trăl nĕr'vŭs sis'tĕm) [TA]
The brain and the spinal cord.

central nervous system (CNS)

The brain and its downward continuation, the spinal cord, which lies in the spinal canal within the spine (vertebral column). The central nervous system is entirely encased in bone and is contrasted with the peripheral nervous system, which consists of the 12 pairs of cranial nerves arising directly from the brain, the 31 pairs of spinal nerves running out of the spinal cord, and the AUTONOMIC NERVOUS SYSTEM.

central nervous system (CNS)

the main mass of nervous material lying between the EFFECTOR and the RECEPTOR organs, coordinating the nervous impulses between the receptor and effector. The CNS is present in vertebrates as a dorsal tube which is modified anteriorly as the BRAIN and posteriorly as the SPINAL CORD; these are enclosed in the skull and backbone respectively. In invertebrates the CNS often consists of a few large cords of nervous tissue associated with enlargements called ganglia (see GANGLION). In some forms, i.e. COELENTERATES, the place of the CNS is taken by a diffuse nerve net. In addition to relaying messages for the sense organs, (in higher organisms at least) the CNS takes on an additional activity of its own in the form of memory which is the storage of past experiences. See also AUTONOMIC NERVOUS SYSTEM.

Central nervous system (CNS)

Part of the nervous system consisting of the brain, cranial nerves and spinal cord. The brain is the center of higher processes, such as thought and emotion and is responsible for the coordination and control of bodily activities and the interpretation of information from the senses. The cranial nerves and spinal cord link the brain to the peripheral nervous system, that is the nerves present in the rest of body.
Figure 1: Ascending nerve pathways and proprioceptive reflex arcs, represented in diagrammatic sections of the brain and spinal cord. Shown on the right: those serving the sensations listed. Shown on the left: reflex pathways for skeletal muscle control. (A) From a muscle spindle, to a synapse with an alpha motor neuron, and a branch to the brain. (B) From a tendon organ, inhibitory branch (broken line) to an alpha motor neuron, and a branch to the brain.

central nervous system

the brain and the spinal cord. See also autonomic nervous system, peripheral nervous system; Figure 1.

central nervous system

; CNS brain and spinal cord

cen·tral ner·vous sys·tem

(CNS) (sen'trăl nĕr'vŭs sis'tĕm) [TA]
The brain and the spinal cord.

central nervous system (CNS),

n that portion of the nervous system consisting of the brain and spinal cord. The portion of the nervous system beyond the brain and cord is known as the
peripheral nervous system.

central

pertaining to a center; located at the midpoint.

central artery
of the optic nerve, the source of the retinal artery. See also Table 9.
central channel
the fast-flowing channel through the capillary bed, the rate controlled by the metarterioles which exert a sphincter-like action on the system.
central convulsions
convulsions arising from stimulation of the central nervous system, as distinct from those caused by lesions elsewhere.
central cord syndrome
injury to the central portion of the cervical spinal cord resulting in disproportionately more weakness or paralysis in the forelimbs than in the hindlimbs; pathological change is caused by hemorrhage or edema.
central diabetes insipidus
central European tick-borne encephalitis
central layer
central of the three layers of gray matter in the cerebellum; the principal cell type is piriform.
central nervous system
see central nervous system.
central peripheral neuropathy
see Boxer progressive axonopathy.
central progressive retinal atrophy
see central progressive retinal atrophy.
central projection law
the laws of physics applied to the primary x-ray beam of photons, e.g. the closer the object being x-rayed is to the film the sharper will be its definition.
central respiratory oscillator
pool of nerve cells in the pons and medulla oblongata which are responsible for the rhythmic to-and-fro movements of respiration.
central retinal degeneration
see retinal.
central sulcus
fissure of Rolando.
central tarsal bone
the bone of the hock which lies between the proximal and distal rows of tarsal bones.
central tendon of diaphragm
see diaphragmatic tendon.
central vein
the centrally placed drainage vessel of each hepatic lobule, receiving blood from the hepatic sinusoids.
central venous catheterization
insertion of an indwelling catheter into a central vein for the purpose of administering fluid and medications and for the measurement of central venous pressure (see below).
central venous pressure (CVP)
the pressure of blood in the right atrium, measured by an in situ catheter in the right atrium, is a much better guide of the degree of vasogenic peripheral failure than is arterial blood pressure. The technique is used mainly in dogs and cats.

nervous

1. pertaining to a nerve or nerves.
2. unduly excitable.

nervous acetonemia
in contrast to the more common form of this disease of cattle, the wasting form, this one is manifested by delirious signs of circling, head pushing, leaning, straddling, forceful licking including themselves, salivation and incoordination. There is a strong acetonuria and odor on the breath.
autonomic nervous system
the branch of the nervous system that works without conscious control. The voluntary nervous system governs the striated or skeletal muscles, whereas the autonomic governs the glands, the cardiac muscle, and the smooth muscles, such as those of the digestive system, the respiratory system and the skin. The autonomic nervous system is divided into two subsidiary systems, the sympathetic system and the parasympathetic system.
It is also divided into central and peripheral sections. The core of the central section is the hypothalamus which receives afferent input from many other parts of the brain including the cerebral cortex. Its efferent output goes to many lower centers in the nervous system that have visceral control as their functions, e.g. the respiratory center in the medulla. The peripheral section consists of nonmedullated nerve fibers that leave the central nervous system in the craniosacral outflow (parasympathetic system) or the thoracolumbar outflow (sympathetic) system, and terminate in effector organs after passing through a ganglion, visible paravertebral ganglia in the sympathetic system, or ganglia embedded in the wall of the target organ in the parasympathetic system.
central nervous system
the portion of the nervous system consisting of the brain and spinal cord. See also nervous, brain, cerebral.
nervous dysfunction
can occur in any of four ways: (1) Excitation or irritation, an increase in the number of electrical stimuli or facilitation in their passage. (2) Release phenomena, from the damping, modifying effects of higher centers; includes spasticity, exaggerated tendon jerks. (3) paralysis, due to reduction or cessation of transmission of nerve impulses. (4) Nervous shock, a temporary cessation of activity in the nervous system as a whole in response to an insult applied to a part of it.
nervous excitation
see nervous dysfunction (above).
nervous paralysis
see nervous dysfunction (above).
peripheral nervous system
the portion of the nervous system consisting of the nerves and ganglia outside the brain and spinal cord.
nervous release phenomena
see nervous dysfunction (above).
nervous shock
see nervous dysfunction (above).
nervous system
the organ system that along with the endocrine system, correlates the adjustments and reactions of an organism to internal and environmental conditions, comprising the central, peripheral and autonomic nervous systems.

Patient discussion about Central nervous system

Q. Fibromyalgia deeply affect the CNS? Do fibromyalgia deeply affect the CNS (central nervous system)?

A. Fibromyalgia is somewhat related to central nervous system. Fibromyalgia can ultimately disrupt the flow of neurotransmitters between the body and the brain. As a result, fibromyalgia can cause the patient to feel continuous pain, and create chronic muscle spasms. In addition, fibromyalgia patients are often subject to abnormally light a sleeping pattern which prevents the normal production of serotonin and growth hormone normally produced during stage 4 (deep) sleep. This inhibits the body’s ability to heal itself, and may contribute to the overwhelming fatigue and depression experienced by those with FMS.

Q. Is fibromyalgia related to Central Nervous System? Is fibromyalgia related to Central Nervous System? Among men and women who is more prone to the symptoms of fibromyalgia?

A. here is a quote from the National Fibromyalgia Association site:

"Little research has been conducted that measures the prevalence of fibromyalgia, and estimates vary widely as to the proportion of male versus female patients. A 1999 epidemiology study conducted in London found a female to male ratio of roughly three to one. However, a 2001 review of the research literature in Current Rheumatology Reports stated the ratio was nine to one."

More discussions about Central nervous system
References in periodicals archive ?
TLR4 is displayed prominently by microglia, the primary immune cells residing in the central nervous system.
They do, however, note that because rubella attacks the circulatory system first, lesions to the central nervous system are associated with circulatory deficits and the attendant lack of nutrition (in the medical sense of abundant blood supply for healing and development) to the adjoining cortex.
is developing novel diagnostics and therapeutics for Parkinson's Disease (PD) and Attention Deficit Hyperactivity Disorder (ADHD) as well as treatments for cancer, autoimmune disease, and central nervous system disorders.

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