| balanced lethal system | <genetics> A population with non-linked, recessive alleles of a gene, where an individual who has two copies of the recessive allele and is therefore homozygous is dead, while an individual who has only one copy of it, and one copy of a different allele (and is heterozygous) survives. (09 Oct 1997) |
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| Bethesda system | Recent classification for categorizing cervical Papanicolaou smears. Origin: Bethesda, Maryland, site of NIH (05 Mar 2000) |
| blood-vascular system | The heart and the blood vessels by which blood is pumped and circulated through the body. (12 Dec 1998) |
| bulbosacral system | parasympathetic part |
| cardiovascular system | The heart and the blood vessels by which blood is pumped and circulated through the body. (12 Dec 1998) |
| Mach Zehnder system | Interferometric system in which the original light beam is divided by a semi transparent mirror: object and reference beams pass through separate optical systems and are recombined by a second semi transparent mirror. Interference fringes are displaced if the optical path difference for the reference beam is greater and this can be compensated with a wedge shaped auxiliary object. The position of the wedge allows the phase retardation of the object to be measured. The Mach Zehnder system was used in a microscope designed by Leitz. (18 Nov 1997) |
| Galton's system of classification of fingerprints | A system of classification based on the variations in the patterns of the ridges, which are grouped into arches, loops, and whorls (A.L.W. Or arch-loop-whorl system). "Arches are formed when the ridges run from one side to the other of the bulb of the digit, without making any backward turn, but no twist; whorls, when there is a turn through at least one complete circle; they are also considered to include all duplex spirals." The abbreviations used in making a record of fingerprint's are: a, arch; l, loop; w, whorl; i, loop with an inner (thumb side) slope; o, loop with an outer (little-finger side) slope. The ten digits are registered in four groups as follows, distinguished by capital letters: A, the fore, middle, and ring fingers of the right hand; B, the fore, middle, and ring fingers of the left hand; C, the thumb and little finger of the right hand; D, the thumb and little finger of the left hand. See: dermatoglyphics. (05 Mar 2000) |
| gamma motor system | The reflex arc consisting of small anterior horn cells and neuroma, their small fibres projecting to the intrafusal bundle producing its contraction, which initiates the afferent impulses that pass through the posterior root to the anterior horn cells, inducing a stretch reflex. Synonym: gamma motor neurons, gamma motor system, Granit's loop. (05 Mar 2000) |
| vascular system | The cardiovascular and lymphatic system's collectively. Synonym: circulatory system. (05 Mar 2000) |
| vasomotor system | The neural systems which act on vascular smooth muscle to control blood vessel diameter. The major neural control is through the sympathetic nervous system. (12 Dec 1998) |
| genital system | The complex system consisting of the male or female gonads, associated ducts, and external genitalia dedicated to the function of reproducing the species. Synonym: reproductive system. (05 Mar 2000) |
| genitourinary system | The organs concerned in the production and excretion of urine, together with the organs of reproduction. (12 Dec 1998) |
| vertebral-basilar system | The arterial complex comprising the two vertebral arteries joining to form the basilar artery, and their immediate branches. (05 Mar 2000) |
| vertebral venous system | Any of four interconnected venous networks surrounding the vertebral column; anterior external vertebral venous plexus, the small system around the vertebral bodies; posterior external vertebral venous plexus, the extensive system around the vertebral processes; anterior internal vertebral venous plexus, the system running the length of the vertebral canal anterior to the dura; posterior internal vertebral venous plexus, the system running the length of the vertebral canal posterior to the dura; the latter two constitute the epidural venous plexus. Synonym: plexus venosus vertebralis, Batson's plexus, vertebral venous plexus. (05 Mar 2000) |
| cartilaginous part of skeletal system | The part of the skeleton composed of cartilage. Synonym: pars cartilaginosa systematis skeletalis. (05 Mar 2000) |