Capillary

“ These are the communications of the capillary system that explain how the skin becomes livid on the place on which a dead body has for a long time lain, as on the back, for example; how by turning a dead body, so that the head may hang down, it becomes full of fluid; how, on the contrary, by placing upright the body of one dead from apoplexy, asphyxia, &c. the capillary system of the face is freed in a great measure from the blood it contained ”

“ All over the body there are, though you can not see them, networks of capillaries. All the arteries end in capillaries, and in them begin all veins. Supposing a little blood-corpuscle be squeezed in the narrow pathway of a capillary in the muscle of the arm. ”

“ In the body the blood within the capillary is a stream of raw material about to be made muscle, or bone, or brain, and of stuff which, having been muscle, or bone, or brain, is no longer of any use, and is on its way to be cast out. The actual making of muscle, or of bone, or of brain, is carried on, and the work of each is done, outside the blood, in the little plots of tissue into which no red corpuscle comes. ”

“ In the first place, the majority of these nuclei have not the form 204of the nuclei of the capillary, and in the second place these nuclei are situated on the outside of the capillary wall. Whoever has examined the capillaries of the frog’s muscle knows that just such or the same nuclei belong to nerve-fibres, supplying the capillary wall. In the mammal of course these nuclei are smaller and not so conspicuous, nor can we procure pieces of capilliary of any length (the structures under examination here, not being in one plane.) ”

“ The capillaries are spread so thickly that there are not many places in the body where living cells are more than a very small fraction of an inch from one of them. The cells do not, however, lie right against the capillaries, but are separated from them by tiny spaces filled with tissue fluid. In order for material to get from the blood to any living cell, then, it must pass through the wall of the capillary into the fluid which fills the tissue space and from that in turn to the cell itself. ”

“ The diseases of their capillary system are no doubt different from those of animals in their progress and their nature; but they exhibit always the same general character, because they are derived from the same properties, organic sensibility and insensible contractility. ”

“ That property of liquids known as capillary attraction has been frequently called to the aid of perpetual-motion seekers, and the fact that although water will, in capillary tubes and sponges, rise several inches above the general level, it will not overflow, has been a startling surprise to the would-be inventors. ”

“ Capillaries branch without diminution in caliber, and these branches anastomose to form capillary networks, the meshes of which differ in size and shape in different tissues and organs. The largest meshed networks occur in the serous membranes and in the muscles; and the smallest occur in the glands, such as the liver.
The walls of the arteries are thick and stand open when empty, owing to the elastic tissue contained in their walls, while the walls of the veins collapse when empty, owing to their containing a smaller amount of elastic tissue. ”

“ At the beginning the bone cells are lying near one of the tiny blood vessels known as capillaries, which are the exchange stations for material between blood and the stationary part of the body fluid. Thus these cells are favorably located for obtaining materials from which bone can be constructed. As they proceed with the formation of bone they always leave tiny passages open between themselves and the blood capillary. ”

“ The smallest fibres become rigid; the minute capillary vessels corrugate, admit no fluids to pass through them, and at length change into fibres; the larger blood-vessels grow hard and narrow; in short, all the outlets of the body become contracted, and in a manner close: whence the dry, shrivelled, and inflexible state of old age. ”

“ The capillary vessels were not known in Harvey's time: the capillamenta of Cæsalpinus were not the 10 capillaries, but the νευ̂ρα (Greek: neura) of Aristotle. It was believed that the blood, between the smallest arteries and the smallest veins, made its way through "blind porosities" in the tissues, as water percolates through earth or through a sponge. The first account of the capillaries is in two letters (De Pulmonibus, 1661) from Malpighi, professor of medicine at Bologna, to Borelli, professor of mathematics at Pisa. ”

“ The capillary circulation exists in the cartilages, the tendons, the ligaments, &c. in which the nerves of animal life do not enter. Inflammation, which is only a derangement, an increase of this capillary circulation, takes place in these organs, as well as in those that are220 the most nervous; what do I say? where the nerves are the most numerous, this affection is not the most frequent; the muscles are an example of this. ”

“ In addition to forming the organs, the tissues are also grouped in such a manner as to provide supports for organs and to form cavities in which organs are placed. The various cavities of the body are of particular interest and importance. The three largest ones are the cranial cavity, containing the brain; the thoracic cavity, containing the heart and the lungs; and the abdominal cavity, containing the stomach, the liver, the intestines, and other important organs (Fig. 2) . Smaller cavities serving different purposes are also found.
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“ If we pursue our researches into the interior of this animal, we find within the framework of the skeleton a great cavity, or rather, I should say, two great cavities,–one cavity beginning in the skull and running through the neck-bone, along the spine, and ending in the tail, containing the brain and the spinal marrow, which are extremely important organs. The second great cavity, commencing with the mouth, contains the gullet, the stomach, the long intestine, and all the rest of those internal apparatus which are essential for digestion ”

“ A demand for a crucial examination of the skull, the heart, lungs, of the chest, the stomach, liver and other organs of the abdomen is made. The septum of the brain, the pericardium of the chest—the diaphragm of the abdomen which is a dividing septum between the abdomen and chest. In this examination we must know the reasons why any organs, vessel or any other substance is located at a given place. We must run with all the rivers of blood that travel through the system. ”

“ Brain cavity absolutely larger, and, in proportion to the size of the body, much more capacious than in the Simiidæ, yet less so than in the Hominidæ. Capacity of the skull about two-thirds the average of that of man. ”

“ The advantage of this arrangement is, of course, in the very large surface which it gives; every one of the individual lung sacs has its wall filled with capillaries and there are so many of the tiny individual sacs that the total surface over which the blood is spread is measured in hundreds of square feet. We cannot imagine any other arrangement by which so large a surface of exposure could be packed away into a cavity the size of the human chest. ”

“ We may well reckon up Fifteen distinct Parts, which are the Bone, the Cartilage, the Ligament, the Tendon, the Membrane, the Fibre, the Nerve, the Vein, the Artery, the Flesh, the Fat, the Skin, the Scarf-Skin, the Hair, and the Nails.
What is a Bone?
It is the hardest and driest Part of the whole Body, and that which constitutes its principal Support. ”

“ The capillaries are intermediate between the arteries and the veins, the final division of the arteries and the first source of the veins. They are tiny vessels with but a single coat, continuous with the innermost coat of both arteries and veins and consisting practically of one layer of cells with a small amount of connective tissue between. [Pg 29] They spread in a great network throughout the tissues, forming plexuses and being especially abundant where the blood is needed for other purposes than local nutrition, as in the secreting glands. ”

“ When ossification sets in, the ear-capsule forms three bones, of which two fuse with the supraoccipital and exoccipitals.
During the formation of the ear-capsule the cranial basis develops from a plate to a trench, for in its hinder section the side parts grow up to form the side walls of the brain, in exactly the same way as the processes of the vertebral rudiments grow up to enclose the spinal column (pp. 122, 192) . The foundations of the skull are now complete, and ossification gradually sets in.
Fig. 11.—Embrionic Cranium of the Adder. Ventral Aspect. (After Rathke.) ”

“ Fig. 9 is a good example of human bone, and is a thin transverse section taken from the thigh. When cut across, bone exhibits a whitish structure filled with little dottings that become more numerous towards the centre, and are almost invisible towards the circumference. In the centre of the bone there is a cavity, which contains marrow in the mammalia and air in the birds. When placed under a microscope, bone presents the appearance shown in the illustration. ”

“ If we contemplate the interior of a skull, we shall at once perceive that the inner table has every where penetrated as far as it could into the recesses which open on the surface of the brain. Every convolution has hollowed out its corresponding mould in the vitreous table ”

“ The capillaries or bloodvessels are finer than hairs, and they are so interlaced and interwoven with nerves that it is impossible to put down the point of the finest needle without wounding several of those minute organs. ”

“ In anatomy the term is used to denote a cover or envelope partly or wholly surrounding a structure. Every diarthrodial joint possesses a fibrous or ligamentous capsule, lined with synovial membrane, attached to the adjacent ends of the articulating bones. The term is particularly applied to the sac which encloses the crystalline lens of the eye; to Glisson’s capsule, a thin areolar coat of fibrous tissue lying inside the tunica serosa of the liver ”

“ Compact Bone Tissue.—The compact bone tissue forms the hard outer layer of all bones. It is thickest in the shaft and becomes thin toward the extremities. Through the compact bone tissue approximately parallel with the longitudinal axis of the bone, run canals called Haversian canals, through which pass blood and lymph vessels for the nourishment of the bone and nerves. ”

“ Each orbital cavity is formed by the juncture of some seven bones and communicates with the cavity of the brain through the optic foramen and through the sphenoidal fissure. Above the orbits are arched eminences of skin, the eye-brows, from which several rows of short hairs grow longitudinally and which serve to protect the eyes and to limit the amount of light to a certain extent, as in frowning. ”

“ Blood is a tissue, the intercellular constituent of which is fluid, and as we consider more dense tissues, we encounter all degrees of density of the framework or intercellular substance, until with the additional presence of calcareous elements, we conceive the hardness of bone and dentine. Tissues as a whole, however, are not solid; there are spaces in the supporting structure to admit of the passage of arteries, veins, nerves, and lymphatics. ”

“ The convexity is regulated by the site of application of the blows, the heavier being applied to the central or apical portion of the plate, the weaker to the periphery. A rough general convexity is so produced. The edges of the plate are smoothed with the file, and a few holes bored to allow of the escape of any blood or cerebro-spinal fluid that might tend to collect beneath.
Fig. 60. The Author’s Method of covering in a Gap in the Skull. s., The scalp; pc., The pericranium; p., The plate; g., The gap in the skull (inside the irregular dotted line) ; sc., The scalp-flap. ”

“ The internal region is like a spiral shell, resembling [Pg 63] an auricle at the extremity of the bone, into which as into a vessel the sound passes. Nor is there any passage from it to the brain, but to the palate; and a vein stretches from the brain to it. But the eyes belong to the brain, and each is placed upon a small vein. ”

“ The CELLULAR TISSUE, [2] now called the areolar tissue, consists of small fibres, or bands, interlaced in every direction, so as to form a net-work, with numerous interstices that communicate freely with each other. These interstices are filled, during life, with a fluid resembling the serum of blood. The use of the areolar tissue is to connect together organs and parts of organs, and to envelop, fix, and protect the vessels and nerves of organs. ”

“ The morphological importance of the sections of the body-cavity in the head cannot be over-estimated, and the fact that the walls become developed into the muscular system of the head renders it almost certain that we must regard them as equivalent to the muscle-plates of the body, which originally contain, equally with those of the head, sections of the body-cavity. ”

“ From this room of anatomy you are conducted to the room of histology, in which the eye is aided by powerful microscopes and made acquainted with the smallest arteries of the human body, which in life are of the greatest known importance, remembering that in the room of histology you are still studying anatomy, and what that machinery can and does execute every day, hour, and minute of life. ”

“ THE SURGICAL DISSECTION OF THE STERNO-CLAVICULAR OR TRACHEAL REGION, AND THE RELATIVE POSITION OF ITS MAIN BLOODVESSELS, NERVES, &c.
The law of symmetry governs the development of all structures which compose the human body; and all organized beings throughout the animal kingdom are produced in obedience to this law. The general median line of the human body is characterized as the point of fusion of the two sides; and all structures or organs which range this common centre are either symmetrically azygos, or symmetrically duplex. ”