lymphatic system (redirected from Lymphoid organs)

system /sys·tem/ (sis´tim)

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. a school or method of practice based on a specific set of principles.

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alimentary system  digestive s.

auditory system  the series of structures by which sounds are received from the environment and conveyed as signals to the central nervous system; it consists of the outer, middle, and inner ear and the tracts in the auditory pathways.

autonomic nervous system  the portion of the nervous system concerned with regulation of activity of cardiac muscle, smooth muscle, and glands, usually restricted to the sympathetic and parasympathetic nervous systems.

Bethesda System  a classification of cervical and vaginal cytology used in cytopathologic diagnosis.

cardiovascular system  the heart and blood vessels, by which blood is pumped and circulated through the body.

CD system  [c luster d esignation] a system for classifying cell surface markers expressed by lymphocytes based on a computer analysis grouping similar monoclonal antibodies raised against human leukocyte antigens.

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  (CNS) the brain and spinal cord.

centrencephalic system  the neurons in the central core of the brain stem from the thalamus to the medulla oblongata, connecting the two hemispheres.

chromaffin system  the chromaffin cells of the body considered collectively.

circulatory system  channels through which nutrient fluids of the body flow; often restricted to the vessels conveying blood.

colloid system , colloidal system see colloid (2).

conduction system of heart  a system of specialized muscle fibers that generate and transmit cardiac impulses and coordinate contractions, comprising the sinoatrial and atrioventricular nodes, bundle of His and its bundle branches, and subendocardial branches of Purkinje fibers.

digestive system  the organs concerned with ingestion, digestion, and absorption of food or nutritional elements.

endocrine system  the glands and other structures that elaborate and secrete hormones that are released directly into the circulatory system, influencing metabolism and other body processes; included are the pituitary, thyroid, parathyroid, and adrenal glands, pineal body, gonads, pancreas, and paraganglia.

enteric nervous system  the enteric plexus, sometimes considered separately from the autonomic nervous system because it has independent local reflex activity.

extrapyramidal system  a functional, rather than anatomical, unit comprising the nuclei and fibers (excluding those of the pyramidal tract) involved in motor activities; they control and coordinate especially the postural, static, supporting, and locomotor mechanisms. It includes the corpus striatum, subthalamic nucleus, substantia nigra, and red nucleus, along with their interconnections with the reticular formation, cerebellum, and cerebrum.

genitourinary system  urogenital s.

haversian system  a haversian canal and its concentrically arranged lamellae, constituting the basic unit of structure in compact bone (osteon).

heterogeneous system  a system or structure made up of mechanically separable parts, as an emulsion or a suspension.

His-Purkinje system  a portion of the conducting system of the heart, usually referring specifically to the segment beginning with the bundle of His and ending at the terminus of the Purkinje fiber network within the ventricles.

homogeneous system  a system or structure made up of parts which cannot be mechanically separated, as a solution.

hypophysioportal system , hypothalamo-hypophysial portal system the venules connecting the capillaries (gomitoli) in the median eminence of the hypothalamus with the sinusoidal capillaries of the adenohypophysis.

immune system  a complex system of cellular and molecular components having the primary functions of distinguishing self from not self and of defense against foreign organisms or substances.

International System of Units  see SI unit, under unit.

keratinizing system  the cells composing the bulk of the epithelium of the epidermis, which are of ectodermal origin and undergo keratinization and form the dead superficial layers of the skin.

limbic system  a group of brain structures (including the hippocampus, gyrus fornicatus, and amygdala) common to all mammals; it is associated with olfaction, autonomic functions, and certain aspects of emotion and behavior.

locomotor system  the structures in a living organism responsible for locomotion, in humans consisting of the muscles, joints, and ligaments of the lower limbs as well as the arteries and nerves that supply them.

lymphatic system  the lymphatic vessels and lymphoid tissue, considered collectively.

lymphoid system  the lymphoid tissue of the body, collectively; it consists of (a) a central component, including the bone marrow, thymus, and an unidentified portion called bursal equivalent tissue; and (b) a peripheral component consisting of lymph nodes, spleen, and gut-associated lymphoid tissue (tonsils, Peyer's patches).

lymphoreticular system  the tissues of the lymphoid and reticuloendothelial systems considered together as one system.

masticatory system  the bony and soft structures of the face and mouth involved in mastication, and the vessels and nerves supplying them.

metric system  a decimal system of weights and measures based on the meter.

mononuclear phagocyte system  (MPS) the set of cells consisting of macrophages and their precursors (blood monocytes and their precursor cells in bone marrow). The term has been proposed to replace reticuloendothelial system, which does not include all macrophages and does include other unrelated cell types.

muscular system  the muscles of the body considered collectively; generally restricted to the voluntary, skeletal muscles.

nervous system  the organ system which, along with the endocrine system, correlates the adjustments and reactions of the organism to its internal and external environment, comprising the central and peripheral nervous systems.

parasympathetic nervous system  the craniosacral portion of the autonomic nervous system, its preganglionic fibers traveling with cranial nerves III, VII, IX, X, and XI, and with the second to fourth sacral ventral roots; it innervates the heart, smooth muscle and glands of the head and neck, and thoracic, abdominal, and pelvic viscera.

peripheral nervous system  all elements of the nervous system (nerves and ganglia) outside the brain and spinal cord.

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 and liver.

Purkinje system  a portion of the conducting system of the heart, usually referring specifically to the Purkinje network.

respiratory system  respiratory tract; the tubular and cavernous organs that allow atmospheric air to reach the membranes across which gases are exchanged with the blood.

reticular activating system  the system of cells of the reticular formation of the medulla oblongata that receive collaterals from the ascending sensory pathways and project to higher centers; they control the overall degree of central nervous system activity, including wakefulness, attentiveness, and sleep; abbreviated RAS.

reticuloendothelial system  (RES) a group of cells having the ability to take up and sequester inert particles and vital dyes, including macrophages and macrophage precursors, specialized endothelial cells lining the sinusoids of the liver, spleen, and bone marrow, and reticular cells of lymphatic tissue (macrophages) and bone marrow (fibroblasts). See also mononuclear phagocyte s.

SI system  see under unit.

stomatognathic system  structures of the mouth and jaws, considered collectively, as they subserve the functions of mastication, deglutition, respiration, and speech.

sympathetic nervous system  (SNS) 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.

urinary system  the organs and passageways concerned with the production and excretion of urine, including the kidneys, ureters, urinary bladder, and urethra.

urogenital system  the urinary system considered together with the organs of reproduction.

vascular system  circulatory s.

visual system  the series of structures by which visual sensations are received from the environment and conveyed as signals to the central nervous system; it consists of the photoreceptors in the retina and the afferent fibers in the optic nerve, chiasm, and tract.

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lymphatic system

n.

The interconnected system of spaces and vessels between body tissues and organs by which lymph circulates throughout the body.

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Lymphatic system

A connected network of nodes, or glands, that carry lymph throughout the body. Lymph is a fluid that contains the infection-fighting white blood cells that form part of the body's immune system. Because the network goes throughout the body, cancer cells that enter the lymphatic system can travel to and be deposited at any point into the tissues and organs and form new tumors there.

Mentioned in: Acute Lymphangitis, Elephantiasis, Filariasis, Fistula, Laryngeal Cancer, Ovarian Cancer, Radical Neck Dissection, Waldenström's Macroglobulinemia

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lymphatic system,

a vast, complex network of capillaries, thin vessels, valves, ducts, nodes, and organs that helps protect and maintain the internal fluid environment of the entire body by producing, filtering, and conveying lymph and producing various blood cells. The lymphatic network also transports fats, proteins, and other substances to the blood system and restores 60% of the fluid that filters out of the blood capillaries into interstitial spaces during normal metabolism. Small semilunar valves throughout the lymphatic network help to control the flow of lymph and, at the junction with the venous system, prevent venous blood from flowing into the lymphatic vessels. The lymph collected throughout the body drains into the blood through two ducts situated in the neck. The thoracic duct that rises into the left side of the neck is the major vessel of the lymphatic system and conveys lymph from the whole body, except for the right quadrant, which is served by the right lymphatic duct. Lymph flows into the general circulation through the thoracic duct at a rate of about 125 mL per hour during routine exertion. Various body dynamics such as respiratory pressure changes, muscular contractions, and movements of organs surrounding lymphatic vessels combine to pump the lymph through the lymphatic system. The lymphatic capillaries, which are the beginning of the system, abound in the dermis of the skin, forming a continuous network over the entire body, except for the cornea. The system also includes specialized lymphatic organs, such as the tonsils, the thymus, and the spleen. See also Color Atlas of Human Anatomy, lymph, lymph node, lymph vessels, spleen, thymus.

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lymphatic system,

n a widespread network of thin vessels, capillaries, ducts, valves, organs, and nodes that primarily produces, filters, and conveys lymph along with producing various blood cells; maintains the internal fluid environment of the body and transports proteins, fats, and other substances to the bloodstream. The tonsils, thymus, and spleen are other major components of the lymphatic system. Also called
lymph system or
lymphoid system.

Lymphatic system.

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lymphatic system

(limfat´ik),
n a complex network of capillaries, thin vessels, valves, ducts, nodes, and organs that helps to protect and maintain the internal fluid environment of the entire body by producing, filtering, and conveying lymph and by producing various blood cells. See also vessels, afferent and vessels, efferent.

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lymphatic, lymphoid

1. pertaining to lymph or to a lymphatic vessel.

2. a lymphatic vessel.

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lymphatic aplasia

causes distention of other lymphatics where lymph flow is blocked and local edema.

lymphatic ducts

the two larger vessels into which all lymphatic vessels converge. The right lymphatic duct joins the venous system at the junction of the right jugular and subclavian veins and carries lymph from the cranial right side of the body. The left lymphatic duct, or thoracic duct, enters the circulatory system at the junction of the left jugular and subclavian veins; it returns lymph from the cranial left side of the body and caudal to the diaphragm.

lymphatic enlargement

includes distention with lymph as in lymphangiectasia, or thickened as in cutaneous tuberculosis.

lymphatic flow obstruction

by local compression, congenital, segmental aplasia, lymphangitis, lymphadenitis.

lymphatic follicle

see lymph nodule; may be primary or secondary.

inherited lymphatic obstruction edema

inherited as a single recessive in Ayrshire and Hereford cattle; calves are edematous, locally or generally at birth and do not improve; the defect is in aplasia of lymph vessels and nodes.

lymphatic leukemia

see lymphatic leukemia.

lymphatic lumbar trunks

a plexus of lymphatics on the abdominal roof that drain into the cisterna chyli.

lymphatic nodule

see lymph nodule.

primary lymphatic organs

see lymphoid organs.

secondary lymphatic organs

see lymphoid organs.

lymphatic system

the lymphatic vessels and lymphoid tissue, considered collectively. See also circulatory system.

Lymphatic vessels and lymph nodes in the dog. By permission from Aspinall V, O'Reilly M, Introduction to Veterinary Anatomy and Physiology, Butterworth Heinemann, 2004

lymphatic tissue

see lymphoid tissue.

lymphatic vessel obstruction

occurs as a result of pressure from nearby tumors or other space-occupying lesions, because of hypoplasia of lymph nodes in the fetus, in extensive calcinosis, e.g. in Solanum malacoxylon poisoning and in horses not getting sufficient exercise. Called also lymphangiectasia.

lymphatic vessels

the capillaries, collecting vessels, and trunks that collect lymph from the tissues and carry it to the bloodstream; called also lymphatics.