Cardiovascular physiology
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal in Principles of Physiology for the Anaesthetist, 2015
The circulation is organized so that the right heart pumps blood through the lungs (pulmonary circulation) and the left heart pumps blood to the rest of the body (the systemic circulation). The two circulations are in series. The principal types of blood vessels are arteries, arterioles, capillaries, venules and veins. The larger arteries have a high proportion of elastic tissue in their walls. The greatest resistance to blood flow, and hence the greatest pressure drop, in the arterial system occurs at the level of arterioles. Pulsatile flow and pressure is dampened by the elasticity of arteriolar walls and the frictional resistance of the small arteries and arterioles so that capillary blood flow is largely non-pulsatile. Velocity of blood flow is inversely related to the cross-sectional area of the blood vessel. About 65% of the blood volume is located in the venous system, which forms a capacitance system.
The transport and exchange systems: respiratory and cardiovascular
Nick Draper, Helen Marshall in Exercise Physiology, 2014
Arteries and arterioles carry blood away from the heart to the capillary networks that form the gaseous and nutri-ent/waste product exchange beds for the cells of the body. Venules and veins, receiving blood from the capillaries return blood to the right atrium of the heart. Arteries always carry blood away from the heart, while veins carry blood to the heart. In general, arteries carry oxygenated blood (blood that has been supplied with oxygen from the lungs) and veins carry deoxygenated blood (blood which has had some of its oxygen removed by the tissues of the body). The exceptions to this rule are the pulmonary ves-sels; the pulmonary arteries carry deoxygenated blood from the heart to the lungs for oxygenation and the pulmonary veins return blood from the lungs to the left atrium (as can be seen in Figure 6.17). Note, however, that the pulmonary arteries still carry blood awayfrom the heart and the pulmonary veins carry blood tothe heart.
ENTRIES A–Z
Philip Winn in Dictionary of Biological Psychology, 2003
Three types of blood vessel are found: CAPILLARY, VEIN and ARTERY. Capillaries are the smallest and are composed of a thin layer of ENDOTHELIUM. Within tissues capillaries form networks known as CAPILLARY beds to facilitate interactions between blood and tissues. Veins and arteries are larger than capillaries and are both made in much the same way: they have three layers of tissue: an outer layer of connective tissue, an intermediate layer of smooth muscle and an inner layer of endothelium. Arteries always carry blood away from the heart (so the blood tends to be oxygen-rich) while veins always carry blood towards the heart (so veins tend to be oxygen-depleted). Of course, arteries do not narrow in a single step to become capillaries but instead narrow gradually. The intermediate portions are ARTERIOLES. Similarly, when blood is flowing away from capillary beds into veins, they pass through VENULES first, venules being wider than capillaries but narrower than veins. Arteries effectively pump blood through the body, having valves present to facilitate this. The flow is regular but discontinuous, reflecting the pumping of the ventricles: this pumping is effectively measured by taking one's pulse. Veins are less actively involved in moving blood, which tends to drain back to the heart rather than being actively pumped. Bodily movement works to keep blood moving in the veins.
Modelling and simulation of fluid flow through stenosis and aneurysm blood vessel: a computational hemodynamic analysis
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
J. V. Ramana Reddy, Hojin Ha, S. Sundar
Blood vessels play an important role in the circulatory system; These are in the form of tubes that carry blood between the heart and all parts of the body. The blood vessel size varies enormously; in the case of arteries, it varies from 1 mm to 8 µm while 1 mm to 20 µm for veins. An artery carries oxidized blood away from the heart, whereas a vein is the blood vessel that collects and transports blood toward the heart. The general appearance of the arteries is rounded lumen, while veins are irregular and often collapse. As compared to arteries, veins are thin-walled vessels with a large and irregular lumen. The diseases of arteries, veins, and lymph vessels alert to blood flow disorders that affect circulation, thus resulting in disturbance in organ function. An aneurysm is a pathological condition. It weakens the blood vessel wall due to the bulging area in that area, resulting in an abnormal widening or ballooning more significant than 50% of the standard diameter. The arteries are mostly exposed to an aneurysm rather than a vein among the several blood vessels.
Three-Dimensional in Vivo Anatomical Study of Female Iliac Vein Variations
Published in Journal of Investigative Surgery, 2022
Wenling Zhang, Chunlin Chen, Guidong Su, Hui Duan, Zhiqiang Li, Ping Shen, Jiaxin Fu, Ping Liu
The EIV joins the IIV in front of the sacroiliac joint to form the CIV. The bilateral CIV, accompanied by the common iliac artery, converges to the inferior vena cava on the right side of the 5th lumbar spine. Veins usually accompany arteries. April T. Bleich et al. [23] conducted an autopsy of 54 female cadavers and found that only 62.3% (66/106) of the posterior internal iliac arteries and anterior internal iliac arteries shared a common trunk, i.e., 37.7% of the posterior internal iliac arteries were independently issued by the common iliac artery. LePage PA et al. [24] dissected 79 specimens from 42 cadavers and found that 73% of the IIVs of the specimens flowed into the EIV system through a main trunk and that 27% of the IIVs flowed into the EIV system through two completely separated main trunks. Chong GO et al. [20] found that the incidence of main iliac vein separation was 18.3%. In this study, similar manifestations were found when IIV returned to CIV, with an incidence of approximately 34.20%. It was common to observe IIV dividing into two branches or simultaneous confluence with the EIV to form the CIV, while three branches were rare.
Preliminary application and evaluation of autograft reconstruction of parotid duct defect with submandibular gland duct for buccal cancer
Published in Acta Oto-Laryngologica, 2020
Ruohuang Lu, Zhiqiang Xiao, Xincheng Guo, Pingping Gan
There are various anatomical structure differences between veins and parotid ducts. The veins usually need to receive nutrient support from the blood flowing inside. Therefore, vein grafts have long-term nutritional disorders, whereas the parotid ducts and submandibular ducts generally get nutritional support from outside the tube. Comparatively, there is a long-term infiltration of saliva and related digestive enzymes in the parotid duct. The submandibular gland duct has a wall structure similar to that of the parotid duct. After transplantation, it can adapt quickly to the pH of saliva and the environment of salivary digestive enzymes. Chudakov et al. [18], who used the intravenous parotid duct as a transplantation supplement in dogs, found endometrial necrosis, endometrial ablation, and middle and adventitial edema after grafting the vein, and that the vein thickens to 1.5 to 1.8 times up to 14 to 21 days after surgery. Furthermore, it was found that the vein grafts were all replaced by connective tissue 21 days after surgery. Therefore, the proliferation of the graft vein wall may lead to the narrowing of the graft vein.