apothecaries' system (redirected from Apothecaries' system of mass)

apothecaries' system 

a system used for measuring and weighing drugs and solutions, brought to the United States from England during the colonial period; it has now been replaced by the metric system. Its units are the grain, scruple, dram, ounce, and pound. Fractions are used to designate portions of a unit of measure: e.g., one-fourth grain is written gr. 1/4. The fraction 1/2 is written ss. There are two symbols in this system which are sometimes confused and always must be written clearly, those for drams and ounces. Lower case Roman numerals are used after the symbols: ʒiss reads drams one and one-half; ℥iii reads ounces three. See also Table of Weights and Measures in the Appendix.

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system,

n a set or series of organs or parts that unite in a common function.

system, acid-base buffer,

n the system by which a virtually constant pH level of the blood and body fluids is maintained. The base and acid electrolytes associated with normal metabolism are continuously introduced into the bloodstream. Notwithstanding the marked amounts of base or acid or both introduced into the bloodstream during exercise, rest, hunger, or the ingestion of fluid and solid foods, the pH level of the blood remains rather constant between 7.3 and 7.5. Four means by which this relatively narrow but constant pH level is maintained are: the buffer system of the blood, tissue and cell fluids, and mineral salts of the bone matrix; excretion and retention of carbon dioxide by the lungs; excretion of an acid or alkaline urine; and the formation or excretion of ammonia and organic compounds.

system, apothecaries'

n a nondecimal system of weights and measures traditionally used by druggists. See also system, avoirdupois.

system, autonomic nervous,

n See autonomic nervous system (ANS).

system, avoirdupois

n a commercial nondecimal system of weights and measures. See also system, apothecaries'.

system, central nervous (CNS),

n the brain and spinal cord, including their nerves and end organs; controls all voluntary acts.

system, circulatory,

n the heart and blood vessels. Three major groups of blood vessels are defined: arteries, capillaries, and veins. The system transports metabolites to and from the tissue cells.

system, computer,

n an assembly of procedures, processes, methods, routines, techniques, and equipment united by some form of regulated interaction to form an organized whole. It is an approach to a complex problem.

system, flowchart,

n a pictorial diagram illustrating the flow of information into, through, and out of a system of programs.

system, hematopoietic

n a term used to describe collectively the blood, bone marrow, lymph nodes, spleen, and reticuloendothelial cells.

system, masticatory,

n the organs and structures primarily functioning in mastication: the jaws, teeth, and their supporting structures; temporomandibular articulation; mandibular musculature; tongue; lips; cheeks; and oral mucosa and their nerve supplies.

system, metric,

n a decimal system of weights and measures almost universally used in scientific and professional work, including the writing of prescriptions. The individual units are based on an international set of standards, notably the meter, liter, and kilogram. In dentistry, measurement is done by the metric system.

system, musculoskeletal,

n the system of body structures that provides the energy and movement necessary for the functions of life. The muscles, bones, and connective tissues of the body are grouped together into one system, and they are intimately connected in their individual and combined functions. E.g., for muscle to accomplish its ultimate purpose of movement by contraction, bone, leverage, and connective tissue are required to transmit the force that the contraction generates. In the oral cavity and its related structures the musculoskeletal tissues fulfill the mechanical and structural requirements for movement of the mandible and some related visceral functions, such as respiration and digestion.

system, neurohormonal,

n the system by which the hormone secretions of the endocrine glands function in part as the regulators of both visceral and somatic function and have intimate anatomic and functional relationships with the nervous system by the union of the pituitary gland and the hypothalamus of the cerebrum. The pituitary gland has a pars nervosa, which is an extension of the anterior part of the hypothalamus, and a pars intermedia, which is an epithelial evagination of the secretory tissue from the stomodeum of the embryo. From its position in the cranial structures in the sella turcica, the pituitary gland regulates, by its union with the nervous system, the whole endocrine system, with its many glands; these glands in turn partially regulate the viscera and somatic muscle organs.

system, occlusal (occlusal scheme),

n the form or design and arrangement of the occlusal and incisal units of a dentition or of the teeth on a denture. See also system, masticatory.

system, parasympathetic nervous,

n one of the motor divisions of the autonomic nervous system. It is described as the
craniosacral division and does not have the simplified structural apparatus of the strong sympathetic adrenal axis about which to function. It inhibits the heart, contracts the pupils, and, in emotional states, produces a vagus-insulin axis of activity. The several parts function rather independently. The ocular division relates to the midbrain, and the bulbar division relates to the hindbrain. The bulbar division supplies the facial, glossopharyngeal, and vagus nerves. It also supplies the secretory and vasodilator fibers of the salivary glands and mucous membranes of the oral cavity and pharynx. In conditions of very loud noise or unusual anxiety states, the parasympathetic system causes unaccounted-for spontaneous urination, excessive salivary and gastric juices, and either nausea or vomiting.

system, proaccelerin-accelerin,

n See factor V.

system, proconvertin-convertin,

n See factor VII.

system, stomatognathic,

n the combination of all the structures involved in speech and the reception, mastication, and deglutition of food. The system is composed of the teeth, jaws, muscles of mastication, epithelium, and temporomandibular joints and nerves that control these structures.

system, sympathetic nervous,

n one of the two opposing motor systems in the autonomic nervous system that mediate the activity of the viscera. (The other is the
parasympathetic system.) It is composed of 21 or 22 ganglia in chains on each side of the spinal cord. The fibers connect with the spinal cord through these ganglia. The actions are closely allied to the action of the medulla of the adrenal gland; thus a sympathetic-adrenal axis that functions as a unit to protect and regulate the body environment may be conceived. The sympathetic control is modified by the volitional somatic control of the patient. The volitional control, superimposed on the autonomic control, gives rise to great variations in motor patterns, as seen in the face in the presence of emotional changes, such as in the blushing of shame and pallor of fear.

system, vascular, closed tube,

n the type of vascular system, as in humans, in which the blood circulates through the vessels (or tubes) and is not dissipated into the tissues. The closed vascular tube system offers resistance to the pumping action of the heart because the pressures are cumulative with each pumping action. The elastic walls in the arterial vessels, particularly in the aorta, absorb the additional energy and release it slowly, thus creating the possibility of maintaining a fairly steady and safe pressure head throughout the vascular system. The high-pressure point at the height of cardiac contraction is the
systole, and the low point before the ventricular contraction is the
diastole.

system, vascular, open tube,

n in some vertebrates a vascular system with an open end that causes the blood fluid to dissipate into the tissues. This system starts with a maximal head pressure that diminishes until inertia in the blood is overcome. The blood is returned to the heart by muscle function, gravity, and diffusion. The blood pressure in this system fluctuates from a maximum at the heart to a minimum at the tissue cell.

system, venous,

n a system of interconnected blood vessels that returns blood to the heart from the tissue and capillary bed through progressively larger vessels. The following affect the return of blood to the heart: thoracic pressure, associated with respiration; gravity, associated with body posture; the valves, diameter of the lumen, and muscle structure of the veins; muscle contraction of the somatic structures; the pressures in the arteriole system and capillary bed; and the nervous and hormonal system controls that regulate cardiomuscular activity. The influences over the venous system circulation are collectively termed
venopressor mechanisms.