Final answer:
A significant cause of venous thrombosis is all of the above: altered blood coagulation, stasis of blood, and vessel wall injury, which can be caused by genetic or acquired factors and can be exacerbated by venoconstriction.
Step-by-step explanation:
A significant cause of venous thrombosis includes altered blood coagulation, stasis of blood, and vessel wall injury. Venous thrombosis is a condition where thrombi form within a blood vessel, which may lead to complications like deep vein thrombosis or atherosclerosis. Factors contributing to thrombosis can be genetic or acquired, such as from conditions like thrombocytosis, polycythemia vera, and lifestyle factors like long periods of immobility.
Venoconstriction, the constriction of a vein, can result in increased blood pressure within the vein, reducing blood flow within the vein, and potentially affecting the return of blood to the heart. If a thrombus impedes blood flow, it will necessitate the heart to generate more pressure to maintain circulation.