A tendon is a hard, substantial, flexible, and elastic body, which, at the head of the muscle, is very compact; but as it enters the muscle, spreads its fibres over the whole body, gathers again at the tail, in as compact a manner as it began, and continues in this chord-like texture till it fastens itself at its appropriated place.[[7]]
[7]. It must be observed however, that tendons take on many various forms, as different as the muscles; which would be too tedious here to particularize.
The tendons and ligaments are of equal substance, and differ in nothing but their various uses; namely, the ligaments to connect the articulation; and the tendons, or the ends of the muscles, to give motion. The muscles are a composition of the tendinous fibres, plentifully intermixed with small ramifications of blood vessels; all which compose the fleshy part thereof. Hence, the tendons being white and hard, the muscles gradually grow softer and redder in the middle of them; and they verge gradually to become tendinous at the tail, the same as the head.
Hence, from the close texture of the tendons, they are very painful when wounded, or otherwise hurt; but as the muscles are softer and more pliable, their wounds and other accidents are of less consequence, and not so dangerous as the former.
The number of muscles are undetermined, for though the principal muscles are so distinct that they cannot be mistaken as to their form and use, yet there is so great a number of small ones, or so many of the great ones capable of being subdivided again, that anatomists have not, as yet, agreed about their number.
SECT. VIII.
Of the Urinary Organs and Genital Parts.
The kidnies, the ureters, the bladder, and the urethra, are the principal urinary organs. The kidnies receive two arteries called the emulgent arteries, from the great arterial trunk, called aorta, before described; they each send also two veins back again, accompanying the arteries to the vena cava. Whilst the blood is circulated in the kidnies, the urine is secreted in many small quantities, and carried from each kidney by a tendinous tube, the bigness generally of a small goose quill, called the ureter to the bladder. The ureters enter the bladder between its lamillas, so as not to admit of a return. Hence, a bladder in its natural position is both wind and water tight, and if reversed, is neither.
The bladder of urine is of a tendinous and nervous texture, and capable of great extension, but at the same time exquisitely sensible. The neck of the bladder is very muscular, and by this forms a sphincter, or annular muscle, by which the urine is retained; and as it is of a very sensible nature, this part is subject to inflammatory constrictions; great pain, and many evils have there been occasioned, either from venereal cases, or gravelous complaints.