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Atrioventricular (AV) and ventriculoatrial (VA) branches of the coronary arteries are vessels which supply simultaneously atrial and ventricular walls by means of recurrent rami. The terminology indicates the name of the main vessel followed by the name of the recurrent vessel both combined in an adjective. These branches establish a vascular ‘suture’ across the coronary sulcus in front (superficially to) or behind (deeply to) the trunks of the right coronary artery and of the left coronary artery (circumflex artery). The AV and VA branches, found in 95% of 40 human hearts, should be considered a normal characteristic of the coronary circulation and an important anatomical factor for the clinical interpretation of pathological cardiac phenomena.

The hepatic veins and their sectors of drainage have been studied in 40 livers of ovines. In 35 organs the venous system was injected with "Neoprene Latex 650" and then dissected; in the other 5 it was injected with vinyl acetate (different colors) in order to obtain plastic models. The authors observed that hepatic lobes and their sectors were drained by the following hepatic veins and their tributaries. Major hepatic veins (left hepatic vein, middle hepatic vein, right hepatic vein(s), hepatic vein of the caudate process and hepatic vein of the papillary process), and minor hepatic veins. The left and the middle hepatic veins were the main vessels to drain the blood from the liver of Ovis aries and ended independently into the caudal vena cava. The right hepatic vein(s) terminated in the caudal vena cava only in 57.1% of the cases as it joined the vein of the caudate process or of the papillary process in 31.4% one or more right hepatic vein(s) occurred in 88.6% of the cases, a single vein being more frequent (51.4%) than two (22.9%) or three (14.3%) veins. In a few cases the vein of the caudate process formed a trunk with the right hepatic vein and/or the vein of the papillary process (11.4%). Alone or in conjunction with others the vein of the caudate process terminated into the caudal vena cava. The vein of the papillary process ended independently into the caudal vena cava, in 71.4% of the cases. Alone or in conjunction with the vein of the caudate process and/or the right hepatic vein, it ended into the caudal vena cava. Minor hepatic vein, opening directly into the caudal vena cava, completed the drainage of the dorsal and medial sectors of the right lobe and the supraportal portion of the caudate lobe. In the vast majority of cases there were no large anastomoses between veins of adjacent anatomicsurgical segments, limited by avascular or paucivascular areas. The venous drainage network was independent and intertwined with the portobilioarterial network. The venous drainage network included in the majority of cases the following anatomicsurgical segments: a) segment of the left hepatic vein (left lobe); b) segment of the middle hepatic vein (quadrate lobe, the supraportal portion of the caudate lobe, the lateral and intermediate sectors of the right lobe; c) segment of the right hepatic vein(s), typically represented by the dorsal sector of the right lobe; d) segment of the vein of the caudate process; e) segment of the vein of the papillary process. The medial sector of the right lobe is drained by the minor hepatic veins. As veias hepáticas e seus setores de drenagem foram estudados em 40 fígados de ovinos. Em 35 órgãos o sistema venoso foi injetado com Neoprene Latex "650" e em seguida dissecado; nos outros 5 órgãos injetou-se acetato de vinyl (cores diferentes) para obtenção de moldes. Foram observados os lobos hepáticos e seus setores de drenagem das seguintes veias hepáticas e suas tributárias: veias hepáticas maiores (veia hepática esquerda, veia hepática média, veia hepática direita, veia hepática do processo caudado e veia hepática do processo papilar) e veias hepáticas menores. As veias hepáticas esquerda e médias.são os principais vasos de drenagem do sangue do fígado de Ovis aries, desembocando independentemente na veia cava caudal. A veia hepática direita termina na veia cava caudal como vaso único em 57,1% dos casos e junta-se à veia hepática do processo caudado ou veia hepática do processo papilar em 31,4% dos casos. A veia hepática direita ocorre em 88,6% dos casos, sendo em número de uma em maior frequência (51,4%), de duas (22,9%) ou de três (14,3%) veias. Em alguns casos a vaia hepática do processo caudado forma um tronco com a veia hepática direita e/ou a veia hepática do processo papilar (11,4%). Sozinha ou em conjunto com outras, a veia do processo caudado termina na veia cava caudal. A veia hepática do processo papilar chega independentemente na veia cava caudal em 71,4% dos casos. Sozinha ou em conjunto com a veia hepática do processo caudado e/ou a veia hepática direita, desemboca na veia cava caudal. Veias hepáticas menores chegam diretamente à veia cava caudal, completando a drenagem dos setores dorsal e medial do lobo direito e da porção supraportal do lobo caudado. Em grande maioria dos casos existem anastomoses entre veias de segmentos anatomo-cirúrgicos adjacentes, limitados por regiões avasculares ou paucivasculares. A drenagem venosa hepática é formada por vasos independentes mas, interpostos com os vasos integrantes da rede portobiloarterial. A drenagem venosa inclui na maioria dos casos os seguintes anatomo-cirúrgicos: a) segmento da veia hepática esquerda (lobo esquerdo); b) segmento da veia hepática média (lobo quadrado, porção supraportal do lobo caudado e setores intermédio e lateral do lobo direito); c) segmento da veia hepática direita, tipicamente representado pelo setor dorsal do lobo direito; d) segmento da veia hepática do processo caudado; e) segmento da veia hepática do processo papilar. O setor medial do lobo direito é drenado pelas veias hepáticas menores.

In 20% of 40 human hearts, AV and VA branches of the coronary arteries supplied the wall of cardiac chambers on the opposite side of the heart. VA branches were more frequent than AV branches and both were observed at the level of the crux cordis (in the diaphragmatic aspect of the heart).

The morphologic development of rabbit ovarian follicles was studied by means of light and electron microscopy 0, 2, 4, 6, 8, and 10 hours after copulation. The progressive changes at the apex of the follicle included extensive edema, hyperemia, and rupture of blood vessels, and then rupture of the follicular wall. Ovulation occurred when the cohesive forces in the cellular layers of the follicular apex became less than the physical forces within the follicle. Most of the morphologic changes in the follicle as it approached ovulation could be related to the effects of locally produced estrogens.

This study utilized SEM and TEM to demonstrate and compare age-associated changes in pineal morphology of young and senile rats. Structural changes observed in this study and interpreted as age-related included (1) an Increase in the overall thickness of the connective tissue capsule with age, (2) an increase in the relative number of connective tissue cells and fibers in the aged pineals, (3) an increase in the number of striated muscle fibers in the connective tissue capsule and pineal parenchyma, (4) increased number of vacuoles, dense vesicles and dense bodies in pinealocytes, (5) mitochondria with dense cores and longitudinally arranged cristae, (6) an increase in size of cytoplasmic lipid droplets and presence of interstitial adipose lobules, (7) the presence of myelin-like figures in the stalk of the pineal gland and (8) an increase in the number and size of concretions in the aged rat pineal. In addition, the post-ganglionic sympathetic nerve fibers and vascular elements were also compared in the two age groups.

Cardiac segments, as practically independent anatomicosurgical units, supplied by the major branches of the coronary arteries, were identified, named, and numbered in 50 human hearts (42 males and 8 females), after vascular injection (vinyl acetate) and corrosion.

The lymphatic system of 40 specimens of Dasypus novemcinctus and 5 of Dasypus sexcinctus, both found in Brazil, were injected with Prussian blue suspension, neoprene latex (followed by partial corrosion). Lymphangioradiographic study was also made. The data concern the lymph nodes, the lymphatic networks, vessels and main trunks. The main features are the following: a few lymph nodes were missing (popliteal, subpubic and ischial); the superficial jugular ll.nn. predominate on the deep ones; the dorsal mediastinal ll.nn. are well developed; a mesentericocolic plexus is formed by the many anastomoses among the mesenteric and cecocolic ll.nn.; at regular intervals there is a concentration of vessels in the submucous network of the small intestine; the submucous network of the colon shows parallel lamellar lymphatic vessels; the mucous-submucous networks are usually independent from the subserous-muscular ones; there are two types of lymphatic networks alternating along the duodenum; folliculi lymphatici aggregati are absent; the lymphatic vessels run in the mesentery independently from the blood vessels; the mesenteric lymphatic vessels present many valves; the vessels from the diaphragm terminate directly in the cisterna chyli; there is a multipolarity of the abdominal lymphatic circulation, i.e., each organ has its own lymphatic tr.

Ventricular myocardium from several adult specimens of hummingbirds (Eupetomena macroura macroura) were subjected to study by electrocardiography and by light and electron microscopy under normal and experimental conditions as provided by injection of 2,4-dinitrophenol (DNP) and ether anesthesia. The birds were captured in Brazil, and were studied because of their high heart rates 428/460 minute on the average, seeking correlations of structure and function under normal conditions as well as after pharmacological stimuli. Under normal conditions, the hummingbird showed a highly developed sarcoplasmic reticulum, many gigantic mitochondrial with numerous tightly packed parallel mitochondrial cristae and tubules, and few small, dark bodies. The amount of sarcosomes is approximately equivalent to that of myofibrils. As seen in longitudinal sections of muscle fibers, often the junctions between successive mitochondria and both indentations of mitochondria and of the nuclear envelope occurred at the level of the Z bands. This gave the impression that contraction of the myofibrils shortened the nucleus and caused it to wrinkle. Most mitochondrial bulged at their middle as if they had been compressed between successive Z bands, suggesting a more resistant area at the level of these bands than in the rest of the myofibril. Almost no glycogen granules were found, probably because the high metabolic rate of the heart did not allow free storage of such carbohydrates. The administration of DNP was responsible for changes in the ECG (tachycardia and other alterations) and in the structure of the myocardium: large dilations in the sarcoplasmic reticulum and the appearance of small spaces in the mitochondria.

The lymphatic system of the sloth (Bradypus tridactylus) was described after the study of five specimens captured in Brazil. The lymphatic system was injected with Prussian blue suspension and neoprene latex (the latter followed by partial corrosion). The description includes lymph nodes, lymphatic networks, vessels and trunks. The distribution of these structures follows the general pattern of other Xenarthra, namely, Dasypus, Euphractus and Tamandua. However, the following peculiarities were noted: the submandibular, popliteal and posterior mediastinal ll.nn., the abdominothoracic subcutaneous lymphatic collecting vessels, the true principal lymphatic trunks, the cisterna chyli, and the thoracic duct were missing in Bradypus tridactylus. The mesenteric ll.nn. do not fuse and their efferent vessels intermingle with those originating from the cecocolic ll.nn. forming a mesenteric lymphatic plexus. The lymphatic vessels arising from the submucous network of the descending and sigmoid colon are arranged as parallel lamellae similar to those in Dasypus. The efferent collecting vessels from several abdominal organs ultimately empty directly in the inferior vena cava and its trunks of origin and those coming from the bronchial ll.nn. lead to the azygos vein. This feature reminds one of the conditions described in some monkeys. The mesenteric postlymphonodal plexus is well developed and because of the absence of intercalated lymph nodes in the labrinthine circulation it resembles that of amphibia and birds.

The submandibular gland in female and male Praomys (Mastomys) natalensis (a South African mul-timammate rodent) was studied using light microscopy and techniques for the demonstration of carbohydrates. Hematoxylin and eosin stain revealed the presence of a single secreting component that gave a strongly positive PAS reaction. Limiting elements of the granular tubules gave a weakly positive PAS reaction. Acidic glycoproteins were evidenced only in granules of the acinar component.

In a series of 61 adult cadavers, the posterior gastric artery was found in 38 (62.3%), originating from the superior aspect of the mid-third of the splenic artery. The posterior gastric artery, running behind the parietal peritoneum of the omental bursa, produced a peritoneal fold before reaching the posterior wall of the superior portion of the gastric body, near the cardiac region, and the fundus. Its high incidence, hidden origin, deep course, and distribution make this artery very important for surgical procedures relating to the stomach, pancreas, spleen, and celiac region. It may be crucial, especially if partial gastric resection of splenectomy have obliterated other gastric vessels.

The principles of construction of the human body, common to mammals and vertebrates, include general bilateral symmetry (or zygomorphism), metamerism, pachymerism (or tubulation), and stratification [1]. In addition to these, it is recognized that the body is made up of (a) cells or biological units; (b) supracellular functional units, such as nephrons and osteons; (c) tissues; (d) organs; and (e) systems or apparatuses.

Amiodarone and its major metabolite, desethylamiodarone, were measured in the plasma, white blood cells (WBCs) and red blood cells (RBCs) of 14 patients receiving chronic amiodarone therapy. The mean plasma concentrations (+/- standard error of the mean) of amiodarone and desethylamiodarone were 2.4 +/- 0.6 and 1.6 +/- 0.4 microgram/ml, respectively. The drug level in the WBCs was 62 +/- 12 micrograms/g protein during the early loading phase and 106 +/- 33 micrograms/g protein during maintenance phase of amiodarone therapy. Desethylamiodarone concentration in the WBCs was 42 +/- 18 and 190 +/- 33 micrograms/g protein during the loading and maintenance phases, respectively. Although a trend in WBC to plasma concentration was seen, there was no linear correlation between these levels. In 1 patient with severe neuropathy, biopsy of the nerve and muscle showed high concentrations of both amiodarone and desethylamiodarone. Although there was a decrease in tissue drug levels, proportionately high tissue:plasma drug levels were detected at the time of necropsy approximately 6.5 months after amiodarone was discontinued in this patient. Neutrophils from all patients receiving chronic amiodarone therapy showed multiple myelin-like polymorphic inclusion bodies (onionoid bodies) upon electron microscopic examination. Our observations suggest that WBC drug concentrations and electron microscopic changes may provide a means of correlating tissue concentrations and of following patients receiving chronic amiodarone therapy.

The intraparenchymatous veins of the kidney include the venae interlobares, arcuatae, interlobulares, and the venulae rectae and stellatae. The confluence of these vessels usually forms three major ‘segmental’ veins, which represent the ‘roots’ of the right and left renal veins [1]. The arcuate veins describe an arch around the base of the renal pyramids, show several anastomoses, and receive cortical and medullary tributaries. The interlobular veins have rootlets in the periphery of the renal cortex and constitute veins that run parallel to the surface of the kidney. When 3–5 of these rootlets converge, stellate venulae are formed and, from the center of convergence, originate an interlobular vein; the latter is joined by other small veins and drains into an arcuate vein. The straight venules (venulae rectae) originate from the renal medulla, follow the direction of the corresponding arterial vessels in the pyramids, join each other in groups, and terminate in the arcuate veins. A venous network in the adipose tissue surrounding the kidney is a tributary of the venous perirenal arch, which runs parallel to the lateral margin of the organ. This network is also joined by cortical veins and, in turn, gives branches to the stellate venules (and interlobular veins), to the renal and adjacent veins, such as the colic, suprarenal, inferior phrenic, ureteral, gonadal, and lumbar; through these it is connected to the subcutaneous veins of the lumbar region.

The structure of the yolk syncytial-endoderm complex of the preimplantation yolk sac of the shark is examined by light- and transmission electron microscopy. The yolk syncytium is bounded by a membrane that is anchored to the plasmalemma of adjacent endoderm cells by desmosomes. Enlarged nuclei, rough endoplasmic reticulum, Golgi complexes, mitochondria, and other cellular organelles populate the syncytium. Microtubules and filamentous elements are also observed free in the syncytium. Yolk is present as pleomorphic droplets, the profiles of which are generally spherical but may be vesicular, especially at the periphery of large yolk droplets. Occasionally, large yolk droplets have a paracrystalline configuration. Small yolk droplets are modulated through the Golgi complex of the yolk syncytium, and it is suggested that acid hydrolases are added there. Small yolk droplets released from the maturing face of the Golgi complex are sequestered in membrane-limited packets. The membrane of the packets fuses with the membrane enveloping the yolk syncytium and the yolk droplets are released into the yolk syncytial-endoderm interspace. Subsequently, the yolk droplets are endocytosed by the endoderm. Yolk droplets disperse and fuse to form the large irregular yolk inclusions of the endoderm. Yolk metabolites are transported out of the endoderm through the yolk sac endothelium. The yolk sac endoderm thus mediates the transfer of metabolites from the yolk mass to the extraembryonic circulation.

The promontory has been studied in two series of adult cadavers (155 in Brazil and 82 in the United States) amounting to 237. The material included whites, Negroes, and Mulattoes of both sexes. The pelvic promontory was considered as the ventral most prominent median point of the lumbosacral region, belonging to the superior pelvic aperture. Even though it is more frequently located at the superior border of the first sacral vertebra, the pelvic promontory can be found at the level of the disc between the last lumbar vertebra and the first sacral vertebra. It is very rarely found either at the inferior border of the last lumbar vertebra or at the inferior border of the first sacral vertebra or the superior border of the second sacral vertebra. No racial or sexual differences were found, but in adults the promontory more frequently has an inferior situation than that of the fetus and newborn (disc between the last lumbar vertebra and the first sacral vertebra). In the first ages, as well as in adult cases where the pelvic promontory is located in the inferior border of the last lumbar vertebra or in the disc caudal to it, the terminal line has four portions: "discal", sacral, iliac, and pubic.

Branches of the coronary arteries of normal human hearts, supplying both atria and ventricles, were found by fine dissection and have been named rami atrioventriculares. They comprise atrial branches from ventricular arteries and ventricular branches from atrial arteries. Their incidence was 74% in the 50 adult individuals studied. The subjects had committed suicide with a poison which did not damage the coronary arteries. The atrioventricular branches constitute communications across the coronary sulcus, thus establishing a continuity between the atrial and the ventricular arterial supply. Therefore, there is not invariably a sharp demarcation of blood supply between atria and ventricles, as has been commonly taught. Neither atrial nor ventricular branches consist exclusively of ascending and descending branches of the coronary arteries, as has been assumed. Atrioventricular branches can play a role in collateral circulation and may, in individuals who are born with them, provide an explanation for some of the variability in signs and symptoms incidental to heart attacks.

Adult sloths (Bradypus tridactylus) were studied by electrocardiography and by light and electron microscopy under normal conditions and under experimental conditions as provided for by injection of 2,4-dinitrophenol (DNP) and ether anesthesia. ECG's of the animals indicated heart rates of 45–71/min, which can be considered as the normal heart rate of the sloth under laboratory conditions. Under normal conditions, the contracted ventricular myocardium of the sloth exhibited (a) a wrinkled sarcolemma, (b) the usual pattern of myofibrils and of sarcoplasmic reticulum, (c) small mitochondria with spiked and branched, often anastomosed cristae, including a few small intramitochondrial dark bodies, (d) an amount of sacrcosomes smaller than the amount of myofibrils, (e) many glycogen granules, isolated, in the form of a chain, or as clusters, in subsarcolemmal, intermyofilamentous and perimitochondrial positions, (f) few multivesicular bodies and (g) large flat sections of the transverse tubular system. Injection of DNP (1 mg/kg) caused tachycardia. With ether anesthesia, the ECG showed monophasic action potential of myocardial injury and prolongation of inter or intraventricular condition. Electrically, the sloth's heart responded to hypoxia as do other mammalian hearts. The administration of DNP produced (a) derangement and reduction in number and length of the mitochondrial cristae, (b) disappearance of spikes, connections between the cristae and, consequently, the honeycombed arrangement, (c) increased matricial space in the center of mitochondria which was often filled with a grayish substance, (d) disappearance of small dark intramitochondrial granules, (e) depletion of glycogen particles and (f) few dilations in the sarcoplasmic reticulum.

The lymphatic system of 45 Didelphys azarae and 15 Didelphys marsupialis, both species found in Brazil, were studied after injection of Prussian blue suspension and neoprene latex (the latter followed by partial corrosion). The data concern the lymph nodes, the lymphatic networks, vessels and principal trunks. The lymph nodal system in Didelphys is less developed (several nodes are missing) than that of the rodents of the same size. In Didelphys, the posterior cranial mediastinal lymph nodes are well developed: the right node receives the lymph from the stomach and diaphragm through vessels draining the para-esophageal, anterior mediastinal and caudal bronchial nodes, a fact not yet observed in other mammals. Each organ or area has its own lymph nodal station. The posterior para-aortic lymph nodes are almost always absent in the males, while in females only the right one is found. The common iliac lymph nodes are missing and it seems that they are replaced by lymphatic dilatations. Only one lymph node is found for the small intestine and two for the large intestine. The lymphatic networks are simple — 4–5 patches are found in the small intestine and one is constant in the terminal ileum. Other features are the separate drainage of each vaginal cornu and the partial duplication of the thoracic duct.

The interrelated processes enabling the ovum to be released from the mammalian ovary have been the subject of many investigations, which resulted in the advancement of several hypotheses; none, however, can as yet totally explain the morphophysiologic events leading to and responsible for ovulation.This investigation deals with a comprehensive light and electron microscopic study of the morphologic changes related to ovulation in the rabbit. Moreover, an attempt is made to establish a correlation between the modification of the follicle and perifollicular structures and their most likely causal factors.The morphology of the non-stimulated follicle is illustrated in Figure 1. Following copulation, follicles were removed at 2,4,6,8 and 10 hours, processed for electron microscopy, and comparable electron micrographs taken. As expected, the apex of the preovulatory follicle exhibited the most dramatic changes since it is the site where ovulation takes place.

UNTIL recently, little was known about the mechanisms responsible for gastrointestinal motility. At the turn of the century, Bayliss and Starling 1 described peristalsis as a wave of relaxation followed immediately by a wave of contraction which moved the bolus of food along the digestive tract. Although this phenomenon can be demonstrated to occur in the intestinal tract of some lower animals, present evidence suggests that comparable peristaltic waves occur only in the esophagus of man. In the small intestine of man peristalsis consists of a coordinated wave of activity in which contraction of the outer longitudinal muscle is 90° out of phase with that of the inner circular muscle. The circular muscle narrows the lumen while the longitudinal muscle opens the lumen and shortens the segment of the bowel involved. Gastrointestinal motor activity has been characterized as either propulsive, as previously described, or pendular. Pendular movements, also known as