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pulse, in anatomy
pulse, in botany
pulse, in botany, common name for members of the Fabaceae (Leguminosae), a large plant family, called also the pea, or legume, family. Numbering about 650 genera and 17,000 species, the family is third largest, after the asters and the orchids. Some botanists divide the Fabaceae into three or more separate families, but most species share certain common and easily recognizable features. The leaves are usually compound; the fruit is a legume (a type of pod); and the blossoms may have an irregular butterflylike (papilionaceous) shape. Typically, the flowers have 10 stamens, and the corolla and the calyx are formed of 5 petals and 5 sepals, respectively. Some species have thorny branches.
The Fabaceae include herbs, shrubs, and trees distributed throughout the world in a great variety of forms. Arboreal species occur in temperate and, frequently, in tropical zones, where epiphytic and climbing forms also thrive. Many leguminous shrubs and trees inhabit desert and semiarid regions, usually forming the characteristic vegetation—e.g., the acacias of the S African bushveld and of Australia, and the mesquite of the American Southwest.
The Pulses and Their Uses
Economically, the family is second only to the grasses in importance. Legumes provide valuable and nutritive foods because the food stored for the embryo in the seed (e.g., the pea) is rich in protein. In many regions, especially where meat is scarce or expensive, legumes—notably peas, beans, lentils, peanuts, carob, and soybeans—are staples of the diet. The Fabaceae are equally important as fodder and forage plants; clover, alfalfa, vetch, lupine, beggarweed, lespedeza, sainfoin, and soybeans are among the numerous valuable types.
These food and forage legumes are chief among the plants used as “green manure” (see manure). Nitrogen-fixing bacteria dwelling in nodules of the roots of most legumes fix free nitrogen from the air into the nitrogenous compounds needed by all forms of life for building proteins (see nitrogen cycle). Rotation of leguminous crops with nonleguminous crops has long been a standard agricultural practice; the soil is enriched when their roots are left to decay after harvesting.
The pulse family also provides gums and resins (e.g., tragacanth, copal, and acacia and carob gums), dyes and tannins (e.g., from the indigo plant, logwood, brazilwood, and types of acacia and broom), timber (e.g., rosewood, locust, honey locust, and acacia), medicines (e.g., from tamarind, licorice, and senna), perfume oils (e.g., from acacia, black locust, broom, and sweet pea), vegetable oils (e.g., soybean and peanut oils), and other commercial items such as flavorings, fibers, and insecticides.
In many parts of the world native species of the Leguminosae are of great importance locally, if not commercially. Often every part of the plant finds some use: the pods and leaves for food, beverages, and forage; the wood and stems for building purposes, fiber, and household items; and the leaves, blossoms, and bark for domestic remedies. The blossoms of many of the Leguminosae are excellent honey sources. Species that grow in arid climates are particularly valuable because of the scarcity of other fodder, food, and timber crops; they are also important to wildlife for forage and cover. Native Americans have cultivated bean plants since antiquity and still rely on breadroot, redwood, mesquite, and many other species for food and other products.
Among the native North American trees cultivated for shade or for their beautiful springtime blossoms are the locusts, the honey locust, the yellowwood, the redbud, and the acacias. The mimosas, sennas, laburnums, poincianas, Old World acacias, shrubby brooms, and wisteria have been introduced for the same purpose. The American lupines, the Old World sweet pea, and numerous types of clover are among the cultivated herbaceous species. In all, members of over 140 genera of the Leguminosae are grown for ornament. Furze from Europe and the kudzu vine from Asia have been introduced for erosion control (the latter has become a noxious weed). The locoweeds and lupines of the western states are among the plants poisonous to livestock.
See articles on individual plants.
an annual plant of the Leguminosae family, grown to produce vegetables: beans, peas, French beans, and Vigna (Dolichos lablab). Pulses are rich in protein, carbohydrates, vitamins, and the mineral salts of potassium, phosphorus, calcium, and magnesium. They are grown for their young beans, called shovels, and for their unripe seeds. Both fresh and preserved pulses are used as food. They are dried and frozen.
the rhythmic dilatation of the blood vessels simultaneously with the contraction of the heart, visible to the naked eye and palpable. Palpation of an artery reveals the frequency, rhythm, tension, and other properties of the arterial pulse.
In a healthy adult male, the pulse rate at rest is 60–80 beats per min, with even intervals between the beats. This is altered in arrhythmias: the intervals between beats become irregular and the number of beats may become fewer (as in atrial fibrillation) than the number of heart contractions, the pulse deficit. It is important in diagnosis to determine the arterial pulse, since the pulse wave depends on the systolic volume of blood ejected into the aorta with each contraction of the heart, the correlation between the inflow and outflow of blood in the arterial system, the level of arterial pressure, and the tone and elasticity of the arterial walls.
The pulse wave is distinguished from the pulsating movement of blood in the vessels. A pulse wave moves in the arteries at the rate of 500–1,000 cm/sec and ahead of the linear movement of blood in the aorta, which occurs at the rate of 50 cm/sec. Pulse fluctuations in peripheral arteries result from the pulse wave and not from the systolic volume of blood. The rate of a pulse wave obeys the physical laws of the movement of a pressure wave in elastic tubes: the thicker and less elastic the arterial walls (as in atherosclerosis), the higher the rate of the pulse wave. The rate is determined by graphic methods of registering the pulse. Determination of the pulse is important in the diagnosis of cardiovascular diseases.
I. M. KAEVITSER