Veins


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Related to Veins: capillaries, Spider veins

Veins

 

vessels that transport blood from organs and tissues to the heart. Veins of the systemic circulation collect blood saturated with carbon dioxide, metabolites, hormones produced by the endocrine glands, and other substances from organs and parts of the body and transport it to the right atrium. Veins of the pulmonary circulation return oxygen-enriched blood from the lungs to the left atrium. Food absorbed in the gastrointestinal tract is transferred to the general bloodstream through the portal vein system. The veins originate in the capillary network where venules are formed, and on coalescing the venules form veins. The venous wall is much thinner and more plastic than the arterial wall, and its musculature is relatively weakly developed. Blood pressure is very low in the veins and below atmospheric pressure in the large ones. The flow of blood in the veins is greatly affected by the respiratory movements of the chest (suction) and movements of the diaphragm, while the deep veins of the extremities are affected by muscular contractions. The venous valves along the bloodstream allow blood to flow only to the heart. The numerous nerve endings in the walls of certain large veins (superior and inferior venae cavae, portal vein, and others) take part in regulating blood circulation.

IU. I. DENISOV-NIKOL’SKII


Veins

 

(also, nerves), in plants, the fibrous vascular bundles in leaf blades that perform conducting and mechanical functions. Large veins are formed by several of these bundles and often include strands of mechanical tissues and parenchyma. They are usually in the form of ribs on the lower side (sometimes on the upper side) of a leaf blade. Veins are also located in the petals and sepals of flowers, in fruits, and in plant stems. Veins in insects are hollow, tubular, hardened thickenings in the wing membrane. After the adult insect passes through the pupal or nymphal stages, the veins fill with hemolymph. This creates pressure that straightens the wing. There are both longitudinal and transverse veins, which maintain the stability and aerodynamic properties of the wing.

References in periodicals archive ?
The problem with getting rid of varicose veins is that even when one vein is destroyed, other varicose veins can appear over time.
This report presents a rare variation of the right testicular vein. Presence of five testicular veins at the deep inguinal ring; formation of two testicular veins in the abdomen and their variant termination into the inferior vena cava is the main feature of this report.
As in cases of the hemodialysis catheter insertion into the right atrium, its tip can be moved or erroneously inserted through the inferior vena cava into the hepatic veins and because of malposition's of the catheters, clinicians can observe some problems in hemodialysis sessions associated about this issue.
Varicose veins tend to run in families suggesting a possible genetic predisposition for the condition.
The distance of fistula vein from skin incision at mid arm was found to be consistent from the per op measurement till the last assessment at 6 months.
Dr Oliver says that the link is related to varicose veins occurring where there is an increase in the pressure of veins in the leg - like when you have one leg resting on the other, restricting blood flow.
Researchers confirmed that age, gender, obesity, pregnancy and history of deep vein thrombosis are risk factors for varicose veins, and also found that increased height adds to the risk for varicose veins.
Varicose veins develop due to a problem with tiny valves in the veins of the lower legs.
In their simplest form, they are seen as bulging veins that pop out from legs.
Tampa, FL, January 11, 2018 --(PR.com)-- Vein911[R] Vein Treatment Centers announced today that Dr.
Superficial veins of the upper extremity are the primary location for placement of peripheral IV catheters (PIVC).