Blood Capillary Network Research Articles

New technique to demonstrate the network of blood capillaries of the human retina in their three-dimensional arrangement

A method is presented that demonstrates the whole network of the blood capillaries of the human retina, making it possible (using a dark-field microscope at high magnification) to view the three-dimensional arrangement of this network in different planes by moving the drive of the microscope. The basic principle includes filling the vascular system with oxygen in statu nascendi by injection of H2O2 into the vitreous body of the intact eye and achieving fixation of the retinal tissue by application of a mixture of H2O2 and ethanol, and rendering the dry and flat retinal preparation transparent by soaking it in a specially prepared resin. The retinal vessels are made visible in an optically empty dark field by diffraction of light in a gas-filled specimen. This method allows preparation of the human retinal vasculature in simply enucleated eyes without cannulation of the central retinal artery and, therefore, it may be appropriate to support pathological and anatomical investigations.

Three-Dimensional Organization of Lymphatics and their Relationship to Blood Vessels in Rabbit Small Intestine. A Scanning Electron Microscopic Study of Corrosion Casts

Casts of small intestinal blood vessels and lymphatics in the rabbit were made with methacrylate and observed under a scanning electron microscope (SEM). In casting the lymphatics, a specially diluted low viscosity medium was injected intraparenchymally into the intestinal submucosa. This parenchymal injection allowed good reproduction of fine lymphatics, including the initial lacteals in the villi. The central lacteals were completely surrounded externally by the subepithelial blood capillary networks of the intestinal villi. Individual villi in the lower intestine contained only one central lacteal that drained through a thin lymphatic in the glandular layer into the submucosal lymphatic plexus. Villi in the upper small intestine were broader than those in the lower small intestine, and contained two to five lacteals. They anastomosed with each other at the villous base and formed a markedly expanded sinus. The cast submucosal lymphatics frequently showed constrictions strongly suggestive of valves. It was constantly observed that well-developed lymphatics in the submucosa ran in pairs and held an arteriole or artery between them. This close association of the lymphatics with arteries suggests that arterial vasomotion might provide an important hydrodynamic energy source for lymph formation and transport.

Blood Supply of the Rat Periodontal Space During Amelogenesis as Studied by the Injection Replica SEM Method

Distribution of blood vessels at the labial periodontal space of the rat lower incisor teeth was studied, using Mercox-resin vascular casts, which were coated with gold-palladium and observed in a scanning electron microscope (SEM). Three different layers were identified in the vascular bed of the periodontium. In the inner layer the enamel organ was supplied by a blood capillary network that changed from a circular mesh to a ladder-like pattern during amelogenesis. The middle layer was supplied by small arteries and arterioles. Small arteries originated from the inferior alveolar artery; arterioles, arising from them, became blood capillaries. In the outer layer, the sinusoid veins continued with the blood capillaries which ran into the proximal and the distal sites of the inner layer. This venous layer is located near the alveolar bones. As capillary networks change in pattern during amelogenesis, the circular mesh is considered convenient to provide the required materials for the proliferation and differentiation of inner enamel epithelial cells as well as for early enamel matrix formation, whereas the ladder pattern seems suitable to supply numerous organic or inorganic materials for the advanced enamel matrix formation and calcification.

Enzyme histochemical studies of the lung of domestic fowl. The effects of unilateral pulmonary artery occlusion.

The enzyme histochemistry was studied in the lung of domestic fowl in normal state and after left pulmonary artery ligation (PAL). Immediately after PAL, non‐specific esterase activity increased in the epithelial cells and the tertiary bronchi. Naphthylamidase reaction increased intensely in the epithelium and adjacent structures after PAL. After PAL, air/ blood capillary network showed pronounced tetrazolium reductase activity in a corona‐like circle around bronchi. It was concluded that the active transport mechanisms seem to be disturbed immediately after PAL, but no severe ischaemic changes were observed. A temporary activation of energy yielding process was noted in the capillary network near the tertiary bronchi. A proliferative or inflammatory process is perceptible in the epithelium of the tertiary bronchi and the walls of the bronchial atria.

Distribution of Human Colonic Lymphatics in Normal, Hyperplastic, and Adenomatous Tissue

Prompted by 2 cases of lymphatic metastasis from focal carcinoma in the head of pedunculated adenomas, lymphatics were studied in the colonic mucosa in normal, hyperplastic, and adenomatous tissue utilizing light and electron microscopic techniques. In all three tissues there is a lymphatic plexus associated with the muscularis mucosae, but there are no lymphatics above this level. This explains why lymphatic metastases from superficial intramucosal foci of carcinoma in adenomas do not occur. In lobules of adenomatous tissue, the total distance between the free surface and the muscularis mucosae may be considerably increased, and a focus of carcinoma in adenomatous tissue must at least reach the muscularis mucosae and its lymphatics in order to metastasize. This lack of lymphatics contrasts with the profusion of blood capillaries at the mucosal surface. This may be an example of a more general biological phenomenon in that other sites also concerned with water and ion transport, such as the renal glomerulus, the gallbladder mucosa, choroid plexus, and ciliary body lack lymphatics but exhibit a rich blood capillary network at their transporting surfaces.

Lymphatics of the Human Pulmonary Alveoli: Preliminary Report

The subpleural lymphatics of a normal human lung were injected with a dilute, green-colored latex solution after the lung had been made edematous by normal saline infusions. The tracheobronchial tree was then filled with a white latex, following which the preparation was submerged in concentrated HCl to achieve corrosion of the tissues. Microscopic dissection of the model revealed that there were lymphatic capillary networks not only on the subpleural alveoli but also on alveoli within the lobules. During the microdissection a cluster of intralobular alveoli was found in which the capillary vessels in addition to being injected with latex were also outlined by deposition of carbon particles alongside their walls. This gave credence to the belief that the capillaries were, indeed, lymphatic in nature. The difference between the lymphatic and blood capillary networks have been described.

Diminution of bone blood flow and capillary network in rats during aging.

Diminution of bone blood flow and capillary network in rats during aging.

The Lymphatics of Respiratory Passages and Esophagus

There are many detailed studies on the collecting lymphatic vessels from respiratory passages and the esophagus to the regional lymph nodes. Accordingly, I will describe here the lymphatics of the mucosa of the trachea and the esophagus.The lymphatic system of the mucosa both in the esophagus and the trachea consists of superficial and deep networks of lymphatic capillaries. The superficial network is not situated in the same level of the blood capillary network which lies close to the epithelium, but below the latter. This is a general rule.The superficial network has dense meshes elongated longitudinally along the tube, while the deep network has coarse meshes which are also elongated longitudinally in the esophagus and paries membranacea tracheae, but directed obliquely in the mucosa of the trachea covering the cartilages.In the esophagus the superficial network exists in the lamina propria and the deep network is situated close to the muscularis mucosae, while in the trachea the former is located close to the elastic layer and the latter underneath the layer.Electron microscopically investigated, the structure of the lymphatic capillary in the mucosa of the esophagus shows no great difference from that of the trachea, with the wall composed of a single layer of extremely thin endothelial cells and a basement membrane with breaks or lack here and there. The endothelial cell junctions are wider and looser than those of blood vessels. Further, there are frequently seen endothelial cell junctions that are completely open. In lymphatic vessls valves are discernible and besides similar endothelium and basement membrane, connective tissue and smooth muscles take part in the wall.

Light and Electron Microscopic Observations of the Urinary Bladder Epithelium in the Rhesus Monkey

Our continued interest in urinary bladder epithelium led to a preliminary observation of these cells in the monkey revealing an epithelium many cells in thickness and ultrastructure suggestive of a high rate of metabolic activity at all cell levels. This finding differs from reports on other species where an epithelium of 3 cell layers has been described in mice, rats, rabbits and dogs. To expand this comparative study samples were collected from 10 monkeys. When cut at right angles to the bladder wall the epithelium is 6-12 cells thick with a wide range in cell size and shape (Fig. 1). The epithelium can be arbitrarily divided into 3 zones based on the staining intensity of the cells as observed by light microscopy. The surface layer of oval, pale staining giant cells may display a large round nucleus with dense staining cytoplasmic granules. The intermediate zone 4-8 cells thick shows an increased stain reaction in the cytoplasm and nucleus. A dark staining nucleus is frequently present as well as clusters of cytoplasmic granules of varying stain intensities. In the basal zone the cells are smaller with the nucleus and cytoplasm staining intensely. Prominent intercellular spaces appear to vary in width with the degree of collapse in the bladder wall. Directly beneath the basal cells is a delicate basal lamina, a network of blood capillaries and associated fibroblasts supported on a connective tissue lamina.

The skin of the whale (Balaenoptera physalus).

AbstractSkin specimens were obtained from every representative region of the body of an adult Finback whale (Balaenoptera physalus) and examined by means of various histochemical and histological techniques. The following characteristic features were found:The epidermis is exceedingly thick over the general body surfaces and varies from a maximum of 3.0 mm over the ventral surface to 2.5 mm on the back.The complex understructure of the epidermis has rete ridges oriented to the craniocaudad body axis.The papillary layer of the dermis has long and pointed papillae which are wedged into the epidermis.The sensory cutaneous nerve endings demonstrated by silver impregnation and cholinesterase consist predominantly of small Vater‐Pacini corpuscles situated in the higher level of the dermis.The intricate blood capillary network, positive for alkaline phosphatase is encased in the dermal papillae.There are no hair follicles, sebaceous and sweat glands.

Respiratory Tissue: Structure, Histophysiology, Cytodynamics Part II. New Approaches and Interpretations

This chapter focuses on the alveolar cell. Examination of respiratory tissues from a variety of animal species revealed that there appeared to exist little appreciable difference in alveolar wall structure between most mammalian species. The framework of the alveolar wall is predominantly composed of reticulin. Most of the reticulin occurs in the form of basement membranes. Elastic tissue is present chiefly in the form of individual fibers, which apparently occur at a rather random distribution in the alveolar wall. A higher concentration of the elastic tissue is found at the level of the alveolar duct, particularly surrounding the opening to alveoli. Several distinct cell types are distinguished in the respiratory tissue are: (1) pulmonary surface epithelial cells, ( 2 ) alveolar cells, occurring as two morphological forms, (3) endothelial cells of the pulmonary capillaries, and ( 4 ) migratory blood cells. The dense network of blood capillaries are physiologically the most important components of the alveolar tissue. These are externally protected by the continuous, simple squamous pulmonary surface epithelium, preventing the direct exposure of capillary loops to the alveolar air. A direct connection has to exist between the external environment and the innermost alveolar spaces of the lung, contamination of the latter by inhaled extraneous material cannot be avoided. The alveolar tissue is protected in this respect by millions of alveolar cells, busily engaged in the phagocytosis and ultimate elimination of this material.

RESPIRATORY FUNCTION OF THE SWIMBLADDER OF NOTOPTERUS (LACÉPÈDE)

Some aspects of the anatomy, histology and physiology of the swimbladder of Notopterus have been studied, with special reference to its behaviour in aerial respiration.The large swimbladder with a wide pneumatic duct is reported to function as an accessory respiratory organ. Circulation of blood is modified to discharge this function. The network of blood capillaries covered by a single layer of epithelium apparently facilitates the diffusion of gases between the blood and the swimbladder. Notopterus is able to survive for long periods in foul water, if allowed to reach the surface to take in air. There is a regular exchange of gases between the cavity of the swimbladder and the exterior.The frequency and extent of aquatic and aerial respiration in Notopterus under different conditions have been determined. They throw considerable light on the double respiratory mechanism in the fish.Under normal condition, the mean value of oxygen is 11 per cent and that of carbon dioxide 3 per cent in the “alveolar air” of the swimbladder. The result of analysis of gases from the swimbladder of Notopterus under adverse experimental conditions clearly establishes the remarkable capacity of the swimbladder of the fish to function as an efficient respiratory organ.The presence of a high percentage of carbon dioxide (6.5 per cent) in the swimbladder is of interest and suggests high resistance of the blood of the fish to carbon dioxide.The air‐breathing habit of Notopterus is probably a secondary adaptation to its life in ponds and puddles under tropical conditions.