应用单宁酸-氯化铁法显示小脑不同部位的微血管构筑

目的　光镜下观察 6只大鼠小脑前叶、后叶及蚓部微血管构筑。方法　用单宁酸 -氯化铁法 (TAFM)媒染显示小脑内血管。结果　小脑各部位皮质、髓质动脉均来源于软脑膜动脉和小脑动脉中央支 ,软脑膜动脉分支多以直角进入小脑皮质 ,分别在分子层、蒲肯野细胞层、颗粒层形成毛细血管网 ;小脑后叶髓质中微动脉呈爪状分支 ,小叶两侧皮质深层微动脉或毛细血管可跨过髓质互相沟通。结论　 TAFM显示小脑微血管构筑清晰、立体感强 ,并发现小叶内皮质深层微血管之间有吻合支     

单宁酸-氯化铁法媒染肺内微血管及细胞的组织学观察

目的　光镜下观察大鼠肺微血管及肺组织细胞。方法　应用单宁酸 氯化铁法 (TA Fe法 )灌流固定大鼠 ,取肺做冰冻切片 ,氯化铁显色 ,光镜下观察。结果　肺内小血管、微血管蜿蜒走行 ,被切成各种断面 ,管壁平滑肌细胞、内皮细胞显示清晰 ,有一定立体感 ;接近被膜的微动脉形成较粗的毛细血管 ,肺泡间毛细血管不易分辨 ,肺间质内有微血管和毛细血管分布 ,微血管周围的肺组织亦被媒染。结论　TA Fe法即可显示肺内微血管 ,又能保存组织细胞结构 ,肺内小动脉和微动脉管壁的平滑肌参与微循环的主动调节机制。     

15 人脑海马内部微血管三维构筑的研究

<正>本文采用5例有机玻璃单体铸型标本,暗视野全景观察和日立S—450扫描电镜观察,较完整地显示人脑海马内部血管从动脉—微动脉—毛细血管前括约肌—毛细血管—微静脉—小静脉连续性立体构筑。海马内微动脉与微静脉有着特殊的分布形式,本文观察到一支动脉分细支或数条动脉的分支组成血管网,数支微动脉伴随一条微静脉为-血管单位,毛细血管互相交织成不规则的血管网.皮质动脉分支走向及毛细血管袢长轴与神经纤维走向平行。皮质长、短动脉各序支管随年龄增长而变粗;皮质动脉在深部发支返回浅层。本文观察到微血管间存在多种吻合:1.微动脉间吻合;2.毛细血管前动脉间吻合;3.微动脉与微静脉间吻合;4.微静脉间有搭桥式吻合。微血管形态特征;小动脉壁有卵圆形的内皮细胞核压迹,排列整齐,清晰可见。小静脉壁有圆形的内皮细胞核压迹。较大数量的毛细血管前括约肌和微动脉末端肌纤维包绕管壁形成纹理的微动脉括约肌,微动脉管径突然变细呈锥状与毛细血管相连接。毛细血管汇入静脉,静脉属支呈“树根状”。     

双峰驼胸膜下肺微血管构筑的扫描电镜观察

目的探讨双峰驼胸膜下肺微血管的构筑特征及其功能意义,为哺乳动物肺微血管构筑学研究积累资料。方法铸型扫描电镜技术。结果双峰驼胸膜下肺微血管根据其连续分支可以识别出4级血管：微动脉、终末微动脉、毛细血管前微动脉和毛细血管,胸膜下肺毛细血管通常由该部的毛细血管前微动脉发出,也可由终末微动脉直接发出,并最终相互吻合成胸膜下肺毛细血管网。胸膜下肺毛细血管网粗疏,网孔孔径一般大于毛细血管管径,网孔多呈六边形和五边形。胸膜下肺微动脉、终末微动脉和毛细血管前微动脉的铸型表面均显示有清晰的、环状排列的平滑肌压迹,毛细血管铸型表面可见卵圆形内皮细胞核的压痕。肺间质毛细血管与胸膜下肺微血管之间存在有广泛的、不同水平上的吻合。结论双峰驼胸膜下肺微血管构筑特征与其他哺乳动物比较,并无显著差异。     

胎儿肛管微血管分布特点及其临床意义

目的：研究胎儿肛管微血管的分布特点,为探讨肛门缺血性改变提供微血管的形态依据。方法：墨汁灌注,组织揭层透明铺片及组织切片,光镜下测量胎儿肛管肛门内括约肌及肛膜下区毛细血管网眼密度。结果：胎儿肛管在后中线处肛门内括约肌和粘膜下层存在毛细血管低密度区;肛门内括约肌里微动脉网的干动脉—肌束间动脉走行方向与肌纤维走行方向相垂直,括约肌强度收缩易压迫肌束间动脉,致血供不足。结论：肛管后中线处血供不良和肛门内括约肌痉挛也许是原发性肛裂好发于后连合处的主要原因。     

骨胳肌微血管立体构筑的扫描电镜观察

本文报道应用微血管腐蚀铸型扫描电镜技术,观察了2例3岁男童的翼内肌和咬肌的微血管系统。在扫描电镜下观察,可见微动脉的分支分为三种类型;1.树叉样边分支;2.对称性分支;3.细丛状分支。本文描述了动脉和静脉铸型表面上的内皮细胞核压痕的差别;前毛细血管括约肌压痕的形态特征;拱形动脉的Ⅱ级吻合形式及其生理学意义。毛细血管铸型的直径为5.6±1.9μm。2～3条静脉湍毛细血管汇合成毛细血管后微静脉。可见1条独立的毛细血管直接注入微静脉干。上述形态学因素在骨胳肌的微循环方面,有着重要的生理学意义。     

《外科和放射解剖学》文题摘要(1989年第11卷第1期)

腰大肌的主要动脉腰大肌的血供来源复杂,分别源于腰动脉、髂腰动脉、闭孔动脉、髂外动脉和股动脉。来自骼外动脉的腰大肌支有时虽呈多支型且细长,但有75%是一条且口径较大。腰肌的这种主要动脉可能与老年人及某些竞技运动员的髂外动脉的弯曲有关。     

直肠表面动脉分布与微血管构筑相关性的研究

目的:研究直肠与肛管器官表面动脉分布与器官内小微动脉及毛细血管精确分布间的对应关系.方法:20例成人标本行巨微解剖观察表面动脉分支分布特点;20例胎儿尸体,墨汁灌注,组织切片及揭层透明铺片,光镜观察器官内微血管的构筑情况,测量各部位毛细血管分布密度.结果:器官表面动脉在直肠和肛管呈区域性分布的特点,在上半直肠前壁和直肠颈及肛管后壁中线部位存在"无血管吻合区".微血管测量结果显示上半直肠前壁和直肠颈及肛管后壁中线部位,肌层、粘膜下层及粘膜层毛细血管密度均低于同层其他部位.结论:直肠与肛管表面动脉分布与器官内小微动脉及毛细血管精确分布间存在对应关系,临床可根据肉眼所见表面动脉分布来评估直肠和肛管血供.     

人鼻粘膜微血管管壁的扫描电镜观察

用胰蛋白酶消化-盐酸水解结缔组织法处理成人下鼻甲粘膜标本,然后在扫描电镜下观察了鼻粘膜微血管的管壁结构.毛细血管前微动脉的管壁为分枝平滑肌细胞;在毛细血管前微动脉的末端观察到毛细血管前括约肌;肌性微静脉的中膜由几层环形排列的平滑肌细胞构成.本文还讨论了粘膜微血管管壁结构的机能意义.     

空回肠器官内各层微血管构筑特点及相互关系

目的:为空回肠疾病的机制、手术治疗以及肠移植等提供微血管构筑的解剖学基础.方法:通过墨汁灌注、组织切片、揭层透明、微血管铸型扫描电镜等方法,观察空、回肠肠壁各层微血管构筑特点并探讨其相互关系.结果:空、回肠直动脉进入肠壁后分别向浆膜和肌层发出分支,其中浆膜层微血管较稀疏;肌层微动脉走行与肌纤维方向一致,相互间吻合成网;黏膜下动脉分别向肌层和黏膜层发出返支和分支,构成黏膜层和肌层动脉网;黏膜层微血管形态大体与肠绒毛的轮廓和肠腺窝结构相似;空肠在环肌层、黏膜下层和黏膜层毛细血管密度均大于回肠.结论:黏膜下动脉是肠壁的血供枢纽;空肠壁内各层血供均优于回肠.     

The cytoarchitecture of the wall and the innervation pattern of the microvessels in the rat mammary gland: A scanning electron microscopic observation

This report describes the morphology of the smooth muscle cells, pericytes, and the perivascular autonomic nerve plexus of blood vessels in the rat mammary gland as visualized by scanning electron microscopy after removal of connective-tissue components. From the differences in cellular morphology, eight vascular segments were identified: (1) terminal arterioles (10–30 μm in outer diameter), with a compact layer of spindle-shaped and circularly oriented smooth muscle cells; (2) precapillary arterioles (6–12 μm), with a less compact layer of branched smooth muscle cells having circular processes; (3) arterial capillaries (4–7 μm), with “spidery” pericytes having mostly circularly oriented processes; (4) true capillaries (3–5 μm), with widely scattered pericytes having longitudinal and several circular processes; (5) venous capillaries (5–8 μm), with spidery pericytes having ramifying processes; (6) postcapillary venules (10–40 μm), with clustered spidery pericytes; (7) collecting venules (30–60 μm), with a discontinuous layer of circularly oriented and elongated stellate or branched spindle-shaped cells which may represent primitive smooth muscle cells; and (8) muscular venules (over 60 μm), with a discontinuous layer of ribbon-like smooth muscle cells having a series of small lateral projections. No focal precapillary sphincters were found. The nerve plexus appears to innervate terminal arterioles densely and precapillary arterioles less densely. Fine nerve fibers are only occasionally associated with arterial capillaries. Venous microvessels in the rat mammary gland seemingly lack innervation.     

Revascularization of the freely grafted extensor digitorum longus muscle in the rat

The process of revascularization of free grafts of the extensor digitorum longus muscle in rats has been studied by gross, histological and electron microscopic methods. During the first day after transplantation the muscle is entirely avascular, and it consists of a thin peripheral zone of surviving muscle fibers and a large central area of ischemic muscle. The original blood vessels of the graft undergo a sequence of intrinsic and cell-mediated destruction. Scattered sinusoidal vessels begin to grow into the graft starting on the second day, and ingrowing blood vessels progressively invade the deeper tissues of the graft. Most new vessels form in the connective tissues, but some vessels, especially larger ones, grow into persisting basal laminae from preexisting vessels and, occasionally, even into basal laminae from degenerated muscle fibers and nerves. The differentiation of new arterioles and venules in free muscle grafts is described. By the end of the first week, the entire graft is revascularized, and ultimately a fairly normal relationship between new capillaries and regenerating muscle fibers is established. In mature grafts, however, irregularities are sometimes found in the organization of smooth muscle cells associated with larger vessels.     

单宁酸—金属盐联用媒染脑血管的研究

用２％多聚甲醛，２％戊二醛配伍不同浓度的单宁酸媒染固定液灌流大鼠，取服切片，放入２％氯化铁溶液中呈色，成功地显示了脑内各级血管及毛细血管网的形貌。高倍镜下可见各级血管呈空心管道状，基僻赤多条细纤维丝状结构编织或呈同心圆状排列而成，具有较强的立体感。     

Non-homogeneous blood flow distribution in the rabbit tenuissimus muscle Differential control of total blood flow and capillary perfusion

Structural and functional relationships underlying the blood flow distribution in the rabbit tenuissimus muscle were examined by means of intravital microscopy. A majority of the main feeding arterioles (transverse arterioles) continued into adjacent connective tissue, after giving off branches (terminal arterioles) within the muscle tissue to supply the muscle capillaries. The transverse arterioles thus supplied two vascular areas, although the major part of the arteriolar flow, under normal resting conditions, was distributed to the muscle capillaries—a flow fraction over which the terminal arterioles exerted ultimate control. The fractional distribution of the blood flow between muscle and connective tissue was determined by the relative contributions of the transverse and terminal arterioles to the vascular resistance. These arteriolar segments showed a differential response to an increase in oxygen availability (elevated ambient pO₂), resulting in a total reduction of muscle capillary flow, but no concomitant change in the flow to connective tissue. A decrease in perfusion pressure, on the other hand, led to similar flow changes in the muscle and connective tissue circulation, which was attributed to proportionate resistance changes in the transverse and terminal arterioles. Differences between the larger transverse and smaller terminal arterioles in their sensitivity to various stimuli may form a functional basis for a differential control of arteriolar blood supply and capillary perfusion in this muscle.     

The arterial architecture of the left ventricular wall of human hearts

The normal arterial and microvascular patterns of the left ventricular wall, including the papillary muscles, were studied in 54 human hearts using coronary angiography, arterial and microvascular casts, and histologic sections. According to their shapes and distributions, the arteries in the left ventricular wall may be classified as epicardial, arborized, straight, and papillary. The arborized arteries supply the whole myocardial wall, including some trabeculae carneae, and they anastomose with the straight arteries to form the subendocardial plexus. The papillary arteries have various arrangements: hooked, bifurcated, and tortuous S-shaped. The use of histologic sections and arterial casts revealed no single central core artery and at least two arteries in each papillary muscle. The morphology and blood supply of the anterior and posterior papillary muscles varied somewhat. Scanning microscopy of the arrangement and appearance of arterioles, capillaries, and venules of the left ventricle revealed that large-diameter capillaries, which were sometimes guarded by precapillary sphincters, arose from arterioles. The capillaries were parallel to cardiac muscle fibers and had numerous Y-, H-, and O-shaped anastomotic connections. The small venules were arranged in a fan-shaped fashion in relation to these capillaries.     

Remodeling of the vascular bed and progressive loss of capillaries in denervated skeletal muscle

Very little is known regarding structural and functional responses of the vascular bed of skeletal muscle to denervation and about the role of microcirculatory changes in the pathogenesis of post-denervation muscle atrophy. The purpose of the present study was to investigate the changes of the anatomical pattern of vascularization of the extensor digitorum longus muscle in WI/HicksCar rats 1, 2, 4, 7, 12, and 18 months following denervation of the limb. We found that the number of capillaries related to the number of muscle fibers, i.e. the capillary-to-fiber ratio (CFR), decreased by 88%, from 1.55 +/- 0.35 to 0.19 +/- 0.04, during the first 7 months after denervation and then slightly declined at a much lower rate during the next 11 months of observation to 10% of the CFR in normal muscle. Between months 2 and 4 after denervation, the CRF decreased by 2.4 times, from 58% to 24% of the control value. The loss of capillaries during the first 4 months following nerve transection was nearly linear and progressed with an average decrement of 4.16% per week. Electron microscopy demonstrated progressive degeneration of capillaries following nerve transection. In muscle cells close to degenerating capillaries, the loss of subsarcolemmal and intermyofibrillar mitochondria, local disassembly of myofibrils and other manifestations of progressive atrophy were frequently observed. The levels of devascularization and the degree of degenerative changes varied greatly within different topographical areas, resulting in significant heterogeneity of intercapillary distances and local capillary densities within each sample of denervated muscle. Perivascular and interstitial fibrosis that rapidly developed after denervation resulted in the spatial separation of blood vessels from muscle cells and their embedment in a dense lattice of collagen. As a result of this process, diffusion distances between capillaries and the surfaces of muscle fibers increased 10-400 times. Eighteen months after denervation most of the capillaries were heavily cushioned with collagen, and on the average 40% of the muscle cells were completely avascular. Devascularization of the tissue was accompanied by degeneration and death of muscle cells that had become embedded in a dense lattice of collagen. Immunofluorescent staining for the vascular isoform of alpha-actin revealed preservation of major blood vessels and a greater variability in thickness of their medial layer. Hyperplastic growth of the medial layer in some blood vessels resulted in narrowing of their lumens. By the end of month 7 after denervation, large deposits of collagen around arterioles often exceeded their diameters. Identification of oxidative muscle fibers after immunostaining for slow-twitch myosin, as well as using ultrastructural criteria, has shown that after 2 months of denervation oxidative muscle fibers were less susceptible to atrophy than glycolytic fibers. The lower rate of atrophy of type I muscle fibers at early stages of denervation may be explained by their initially better vascularization in normal muscle and their higher capacity to retain capillaries shortly after denervation. Thus, degeneration and loss of capillaries after denervation occurs more rapidly than the loss of muscle fibers, which results in progressive decrease of the CFR in denervated muscle. The change of capillary number in denervated muscle is biphasic: the phase of a rapid decrease of the CFR during the first 7 months after nerve transection is followed by the phase of stabilization. The presence of areas completely devoid of capillaries in denervated muscle and the virtual absence of such areas in normal muscle indicate the development of foci of regional hypoxia during long-term denervation. The anatomical pattern of muscle microvascularization changes dramatically after nerve transection. Each muscle fiber in normal muscle directly contacts on average 3-5 capillaries. (ABSTRACT TRUNCATED)     

Haematocrit distribution in rabbit tenuissimus muscle

Low values of mean capillary haematocrit have been reported in many tissues including skeletal muscle. The present study was undertaken to analyse haematocrit distribution in the transverse and terminal arterioles, capillaries and venules of the rabbit tenuissimus muscle preparation. Tube haematocrit, i.e. the volume fraction of red cells, in muscle capillaries (n = 85) was found to be 39% of systematic haematocrit Hsys. In part, this haematocrit reduction is due to the Fahraeus effect. Corresponding capillary discharge haematocrit HD was 56% of Hsys. Tenuissimus muscle capillaries are fed by terminal arterioles originating from transverse arterioles. The latter extend into and supply adjacent connective tissue septa in addition to the muscle tissue proper. In transverse arterioles leaving the muscle to enter the connective tissue, HD was found to be 127% of Hsys (n = 18), and in collecting venules at the muscle edge HD was 129% of Hsys (n = 18). These findings indicate that the connective tissue microcirculation represents a functional red-cell shunt in resting tenuissimus muscle. Since only about 20% of the inflow to the preparation passes through the connective tissue, this shunting is not sufficient to satisfy conservation of red-cell mass. In addition, it is likely that the observed low capillary haematocrit is in part due to a positive correlation between blood-flow velocity and HD in capillaries originating from individual terminal arterioles. This phenomenon is called the network Fahraeus effect.     

Scanning electron microscopic studies of the vascular smooth muscle cells and pericytes in the rat heart

The cytoarchitecture of smooth muscle cells and pericytes in the rat cardiac vessels was studied by scanning electron microscopy after the removal of connective tissue matrices using a modified KOH-collagenase digestion method. The initial stem of the coronary arteries had groups of smooth muscle cells which ran in various directions on the outermost layer of the media. Although smooth muscle cells in coronary arteries of more than 100 microm in the outer diameter were arranged in a rough circle around the vessel axis, oblique and/or longitudinal muscle bundles were often present in the medio-adventitial border of the vessels. The presence of irregularly oriented muscular bundles is probably connected with resistance against the stretching force induced by the beating of the heart. As the vessel size decreased toward the periphery, almost all of the smooth muscle cells became spindle-shaped with several tiny processes and ran circularly or helicaly to the vessel axis. In the precapillary arterioles (6-12 microm), smooth muscle cells acquired various cytoplasmic processes which helicaly surrounded endothelial cells. Unmyelinated nerves were often associated with arterioles. Blood capillaries were morphologically divided into three segments: arterial capillaries which had pericytes with wide and circularly oriented processes, true capillaries whose pericytes extended long and thin primary processes bilaterally along the vessel axis, and venous capillaries surrounded irregularly and loosely by wide pericytic processes. The stellate pericytes in the postcapillary venules (10-30 microm) gradually changed into flat tape-like smooth muscle cells, which ran circularly in the collecting venules and veins (30-200 microm). The large collecting veins were finally overwhelmed by superficial thin layer of the myocardium, their own smooth muscle cells being very sparse. This suggests that large veins have poor ability to contract by themselves but are influenced by the surrounding myocardial cells.     

Venulo-arteriolar communication and propagated response

The effect of microinjection of norepinephrine (10^–5 M) into precapillary microvessels of the rat mesentery was studied using intravital microscopy. Upon application, in 29 out of 40 cases (73%) flow ceased at the site of drug application, although in most cases the precapillary microvessels themselves did not show a diameter change due to a lack of smooth muscle cells as confirmed by transmission electron microscopy. In 17 out of the 29 cases with flow cessation (59%), an intimate contact between the venule draining the site of application and the supplying arteriole was found. Initial constriction was seen at the site where the venule crossed the arteriole. Constriction propagated both up- and downstream along the arteriole, and also across arteriolo-arteriolar arcades. Arteriolar constriction could be abolished by intentionally occluding the venule draining the norepinephrine solution. It is proposed that venuloarteriolar contacts and propagated vasomotor response may contribute to local blood flow regulation by providing a feedback loop between tissue capillaries and resistance arterioles. In three complete mesenteric microvessel networks, the arterioles (n=34) supplying 273 out of 401 capillaries (68%) were in close proximity to venules draining these same capillaries. Each of these arterioles served, on average, 43 capillaries, showing a bimodal distribution with peaks at 4 to 16 and at 64 to 256 capillaries. On average, 62% of all capillaries drained by a given venule crossing an arteriole originated from this very arteriole, indicating a reasonably effective feedback.