Development of the microcirculatory bed of the human tongue in the prenatal period

Morphofunctional regularities of formation and development of the blood microcirculatory bed in the human tongue have been studied in the prenatal period of morphogenesis. 119 human embryos and fetuses at the age of 5 weeks--9 months have been investigated. A complex of methods have been used: common histological (hematoxylin--eosin, after van Gieson and Mallory), injection of the lingual vessels with 20% suspension of Indian ink--gelatin, transmissive electron microscopy. General regularities of organogenesis, stages of the blood microcirculatory bed development and peculiarities of the process on formation of the primary protocapillary lingual blood bed are revealed. Regularities in structure of the terminal vascular constructions are studied for each structural element of the organ--mucosal membrane, muscles, glands, lingual tonsil. For these elements at the ultrastructural level certain features of the organic specificity in the structure of the blood microcirculatory bed links are determined.     

The blood microcirculatory bed of the tunica muscularis of the human esophagus in postnatal ontogeny]

The analysis of morphological and morphometrical data of the muscular membrane and its blood microcirculatory bed has demonstrated that their development during the postnatal ontogenesis advances unevenly. An intensified growth and development of the muscular membrane morphological structures, including its blood microcirculatory bed occurs from 3 up to 30 years of life. Their maximal growth is noted from 12 up to 30 years of age. The stages of intensified development of the muscular membrane and its blood microcirculatory bed change into stages of retarded growth, where processes of involutive character preponderate. This is especially noticeable from 60 and more years of age. The stages noticed in the muscular membrane development and its blood microcirculatory bed are characterized both by general and topographical morphofunctional peculiarities specific for every stage of organogenesis.     

Development of the uterine microcirculatory bed in postnatal ontogeny

Age peculiarities of common structure of the microcirculatory pathways, specific volumes and amount of microvessels, zonal parameters of pericapillary microcirculation of metabolites, glycosamine glycans and glycoproteins contents, phosphatase and ATPase activity, collagen and elastic fibers of the microcirculatory bed vessels have been studied in 190 unchanged uteri, beginning from 36-week-old fetuses up to 35 years of age. The microcirculatory bed of myometrium during the period of postnatal ontogenesis investigated possesses a polymer-homonomous structural organization; its base make myoangiomas, including the terminal arteriole with precapillaries and collecting venule, that run from it. Similar structure of the myometrium microcirculatory pathways is already observed in fetuses of late antenatal period. In endometrium formed glanduloangionomas are revealed in the prepubertal age. Increase in glycosamine glycans contents is stated in the microvessel walls and in the uterine stroma during the process of its development. Compensatory-adaptive changes in the uterine microcirculatory bed are described during the newborn period up to the puberty. Functionally mature structures of the microcirculatory pathways in the submucosal and vascular layers of myometrium, endometrium and in the cervix uteri are found to be formed earlier than in other areas of the organ.     

The microcirculatory bed of the human heart

Using a complex approach in studying microcirculatory bed of the human heart, possibilities of scanning electron microscopy of corrosive preparations, those of silver nitrate impregnation after V. V. Kuprianov are demonstrated. The silver nitrate impregnation makes it possible to study the wall structure of the microcirculatory pathways, to analyse arrangement of nuclei in the endothelial and muscle cells of the microcirculatory links, to reveal together with the vessels the surrounding tissues. Scanograms of the corrosive preparations of the arterioles demonstrate "circulatory strips", that are absent in the venular part. The relief of the luminal casts of the microcirculatory bed vessels in the human heart is presented as impresses of nuclei of the endothelial and smooth muscle cells. Peculiarities in form and distribution of these nuclei in various links of the microbed are demonstrated.     

Ultrastructural characteristics of the microcirculatory bed of the human adrenal cortex in prenatal ontogenesis

By means of transmissive electron microscopy the adrenals have been studied in 25 human embryos and fetuses at the age of 6-36 weeks. Certain stages have been revealed in formation of the adrenal cortex microcirculatory bed. In 6-7-week-old embryos (period of diffuse protocapillary bed) endothelial structure and mesenchymal cells, surrounding the adrenal anlage, resemble one another. A distinguished feature of the endothelium is regularly revealed desmosomes and large vacuoles, often found in cytoplasm of endotheliocytes. In 8-12-week-old fetuses (period when the organospecific microcirculatory bed is forming) sinusoid capillaries differentiate in the internal zone of the adrenal cortex; in endothelium fenestrae, "hatches", "locks" are revealed, the capillary basal membrane is formed. During subsequent time of the intrauterine development perfection of the microcirculatory pathways in the adrenals takes place, the arteriolar link of the subcapsular layer including. By the time of birth morphofunctional maturity of the microcirculatory bed in the adrenal cortex is noted.     

Innervation of the microcirculatory bed of the human trigeminal nerve]

The investigation of film preparations and histological sections of human trigeminal nerves impregnated with silver nitrate and treated after Gomori, Falck--Hillarp demonstrated a rich innervation in the intraneural blood vessels. The most various and complex interconnections of the neural structures were noted in arterioles and venules of the node capsule, epineurium and external layers of perineurium of the trigeminal nerve branches. On the vessel walls of these layers, neural plexus were revealed. Sensitive innervation of the neural blood vessels mainly performed by posvalent tissue-vascular receptors. In the walls of intraneural vessels, adrenergic and cholinergic neural plexus are revealed.     

The anatomicohistological characteristics of the formation of the mucosa of the human small intestine in the prenatal period of ontogeny]

The time, when the first villi appear, is defined. Quantitative composition, percent content, height of the villi of the mucous membrane in all parts of the small intestine during various periods of the intrauterine development are presented. In 17-week-old embryos at the level of the duodenum the first villi are noted and their formation in the middle part of the intestinal tube is revealed. By the 8th-9th weeks of development they appear at the level of the caudal part of the intestine. This demonstrates asynchronism of their formation in the cranio-caudal direction. The periods of their intensive growth in height in the first part of the intestine correspond to 8-10, 12-16, 24 weeks of the fetus age, in the second part--to 8-10, 18-20 weeks, in the third--to 10-12, 16-18, 26-28 weeks. These periods alternate with an abatement in growth intensity, which is connected with an increasing width of the villi themselves, with amount of newly formed villi and with changes of the intestinal tube diameter. The form of the villi is rather variable.     

The development of the thoracic duct lymphangions in the prenatal period of human ontogeny]

This paper concerns structural and functional organization of the human lymphatic system during the prenatal period. For the first time the data is presented on the development of thoracic duct based on the concept of lymphangion as a structural and functional unit of a lymphatic vessel. The formation of the duct is considered in connection with structural changes of its wall and variants of duct roots fusion. The following stages are distinguished in the development of the thoracic duct: valval segment stage, protolymphangion, and lymphangion.     

Development of the hemomicrocirculatory bed of the human gonads during the prenatal period of ontogeny

The formation of the organospecific hemomicrocirculatory bed of the ovaries and testes has been studied by a complex of light, transmissive and scanning electron microscopy in 3--9-month-old human fetuses. The change of the diffusive protocapillary bed is secured by: 1) reduction of some protocapillaries; 2) appearance of secondary capillaries from the growth buds of the preceeding microvessels; 3) formation of arteriolar and venular links of the hemomicrocirculatory bed from the protocapillaries at the expense of differentiation of the developing paravasal connective tissue into cellular elements of the muscular and adventitial tunics. The secondary blood capillaries of the human gonads are predominantly formed intraendothelially. During the prenatal ontogenesis presence of the secondary blood capillaries of somatic uninterrupted type is specific for the human gonads.     

Morphofunctional characteristics of the microcirculatory bed of the human spinal dura mater]

Some morphofunctional peculiarities in microcirculatory pathways of the dura mater of the human spinal cord are described. They are concerned with the structure of arteriolo-venular anastomoses through which a rather large amount of arterial blood is transported into the venous bed. Around the vessels of arterial type running at an angle to the longitudinal axis of the vessel connective tissue fibres of the dura mater, there is a tissue layer intensively impregnated with silver salts and stained PAS-positively. The venous part of the dura mater microcirculatory pathways has a large number of accessory reservoirs in the form of venous "lakes". Functional importance of the peculiarities mentioned above for the dura mater and the perimedullar apparatus is clarified.     

Morphology of the microcirculatory bed of the vascular coat of the human eye]

Recently ophthalmologists got interested in microcirculatory bed of the choroid (the main collector of blood in the eye) because of the vascular layer was studied in 25 eyes of persons who had died suddenly and had no eye pathology during their lives. The age was from 11 to 70 years. V. V. Kuprianov's method of impregnation was used. Structural peculiarities of the choroid microcirculatory bed were presented; its changes were stated to depend on functional importance of the given segment of the eyeground and on the age of the patient. The data obtained could facilitate in studying different pathologic conditions in the eye in order to clarify the role of the choroid microcirculatory bed in genesis of ophthalmic diseases.     

The effect of ionizing radiation on the vascular bed of the skin in ontogeny. The function of the microcirculatory bed of the skin in the fetuses of white rats sublethally irradiated]

Albino female rats were exposed to X radiation (5 Gy, 180 kV, 10 mA, filter 0.5 mm Cu) on days 10-15 of pregnancy. After 3 and 7 days they were sacrificed (under ether anesthesia) and fetuses were extracted. The status of the lympho- and hemomicrocirculatory beds (LMCB and HMCB) of the fetus back skin was studied by the macro- and microscopic methods. As early as day 3 of radiation sickness the diameter of LMCB vessels increased by 1.4-1.9 times, whereas changes in GMCB were less pronounced. On day 7, there was a progressive increase in dilatation of LMCB vessels, alongside with the narrowing of large units (arteries and veins). The development of the connective framework of the fetus skin was retarded.     

Synapses of the human brain in early prenatal ontogeny

Synaptogenesis in presumptive cerebral cortex was studied in 7-8 week human embryos by electron microscopy. The first synapses in the regions studied appeared in 7-week embryos. These synapses were detected only in the marginal zone of the developing human cerebral cortex, where they were localized on the somas and processes of the young Cajal-Retzius' neurons. A functional role of early embryonic synaptogenesis in the developing human cerebral cortex is suggested.     

Structure and function of the microcirculatory bed in the preserved heart]

The morphological analysis of the state of the heart during hypertermal perfusion with different conservants reveals clear dependence of the microcirculation and the activity of the heart upon the type of the conservant. Perfusion with a salt solution and hemodilution is accompanied by pronounced disorders in microcirculation and unsatisfactory parameters of the cardiac activity. Conservation with cryoprecipitated plasma is characterized by comparatively less microcirculatory disorders, but fails to give a reliable safety of the heart. When using medium 199, changes in microcirculation were found to be minimal and parameters of cardiac activity were satisfactory. In the complex of non-specific changes in microcirculatory vessels the maximum structural lability was revealed in blood capillaries and vessels of the postcapillary-venular link.     

Study of endothelium-dependent blood oscillations in the human skin microcirculatory bed

Cutaneous microcirculation parameters were studied with laser Doppler flowmetry in healthy volunteers. To investigate endothelial-dependent peripheral blood flow oscillations the iontophoresis of 1% acetylcholine solution was carried out. To estimate the contribution of rhythmical components in blood flow signal the continuous wavelet-transform spectral analysis was used. To reveal correlation between microcirculation parameters under study the correlation analysis was used. The microcirculation index was shown to be the factor producing cross-correlation dependences. The only positive significant correlation between the blood flow oscillation amplitude in the range of endothelial activity normalized to mean microcirculation index at rest and maximal microcirculation index during the iontophoresis of acetylcholine was revealed.     

Changes in the form and ultrastructure of the smooth-muscle cells in the human aorta in prenatal ontogeny]

The shape of smooth muscle cells (SMC) was analysed using the phase contrast microscopy of cell suspensions obtained by alcohol-alkali dissociation, as well as the semithin sections prepared in perpendicular planes. The phenotype of SMC was analysed using transmission electron microscopy. The shape of SMC changes from preferentially round to preferentially spindle-like and stellate one during development. The differentiation of SMC is accompanied with the increase in the contractile apparatus content and in the decrease in the content of synthetic organelles.     

Vascular anastomoses of the blood microcirculatory bed of the human heart

Using a complex of morphological techniques both injective and non-injective, scanning electron microscopy including, the hemomicrocirculatory bed and vascular anastomoses have been studied in various parts of the human heart. In most cases anastomoses between the microcirculatory links are realized at the level of capillaries, precapillary arterioles and postcapillary venules. Venulo-venular anastomoses are demonstrated in the myocardium. Existence of terminal arterioles is discussed.     

Venous stasis and state of the microcirculatory bed in the synovial membranes]

Microcirculatory bed of the synovial membranes was investigated in experiments on dogs during venous stasis. Ligation of the femoral vein and circulatory disturbances led to the alteration of the microcirculatory bed of the synovial membranes, to the overfilling of the venules. Capillary walls became thinner and there developed swellings and protrusions. The extent of the vascular wall changes depended on the calibre of the vessels. One month after the ligation of the vein congestive phenomena in the tissue of the joint capsule proved to decline. This indicated development of collateral venous circulation.     

Structure of the neuromuscular spindles in the tongue of human fetuses

The dynamics in development of some components--of the neuromuscular spindles in the human fetus and newborn tongues have been studied by means of certain general and neurohistological methods with elements of morphometry. During the whole prenatal period of the human life, there is a certain synchronism in the development of the lingual proper muscles and the neuro-muscular spindles. Certain integration in the development of the neuro-muscular spindles is observed in 4-6-month-old fetuses; in 8-9-month-old fetuses and in newborns it is substituted for heterochronicity. By the time of birth, the muscle spindle contractile elements are supplied with a more differentiated efferent innervation. The latter actively effects the morphological state of the intrafusal muscle fibers and forms a base for functional activity of the tongue.