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artery

(Encyclopedia)artery, blood vessel that conveys blood away from the heart. Except for the pulmonary artery, which carries deoxygenated blood from the heart to the lungs, arteries carry oxygenated blood from the hea...

blood transfusion

(Encyclopedia)blood transfusion, transfer of blood from one person to another, or from one animal to another of the same species. Transfusions are performed to replace a substantial loss of blood and as supportive ...

anatomy

(Encyclopedia)anatomy ənătˈəmē [key], branch of biology concerned with the study of body structure of various organisms, including humans. Comparative anatomy is concerned with the structural differences of pl...

hantavirus

(Encyclopedia)hantavirus, any of a genus (Hantavirus) of single-stranded RNA viruses that are carried by rodents and transmitted to humans when they inhale vapors from contaminated rodent urine, saliva, or feces. T...

dementia

(Encyclopedia)dementia dĭmĕnˈshə [key] [Lat.,=being out of the mind], progressive deterioration of intellectual faculties resulting in apathy, confusion, and stupor. In the 17th cent. the term was synonymous wi...

geriatrics

(Encyclopedia)geriatrics jĕrēăˈtrĭks [key], the branch of medicine concerned with conditions and diseases of the aged. Many disabilities in old age are caused by or related to the deterioration of the circulat...

Nematomorpha

(Encyclopedia)Nematomorpha nĕmˌətəmôrˈfə [key], small (about 230 species) phylum of pseudocoelomates; the horsehair worms. Most are very slender, elongated creatures found in ponds and streams, whose larvae ...

earthworm

(Encyclopedia)earthworm, terrestrial, cylindrical segmented worm of the class Oligochaeta. There are 2,200 earthworm species, found all over the world except in arid and arctic regions and ranging in size from 1 in...

mesoderm

(Encyclopedia)mesoderm, in biology, middle layer of tissue formed in the gastrula stage of the developing embryo. At the end of the blastula stage, cells of the embryo are arranged in the form of a hollow ball. Con...

Annelida

(Encyclopedia)CE5 A. The earthworm, Lumbricus terrestris, representative of the phylum Annelida. B. Internal anatomy of an earthworm. Annelida ənĕlˈĭdə [key] [Lat., anellus=a ring], phylum of soft-bodied, ...