valves
Venous blood flow is easiest to control. Arterial blood flow is hardest to control because it is under pressure from the heart.
venous and arterial
Valves aid in venous return by preventing the back flow of blood.
The amount of venous vessel pressure causes the 'venous return' which maintains blood volume. This is driven by the efferent pathway of the sympathetic nervous system which causes the constriction of the blood vessels which pushes the red blood cells in the veins back to the heart (flow is one way due to valves in the veins).
Coagulation or clotting means to stop blood flow.
They prevent back flow and help to return blood to the heart.
Factors that directly influence venous blood flow include venous pressure, intrathoracic pressure changes during respiration, skeletal muscle contractions, venous valves, and sympathetic nervous system activity. These factors help propel blood back to the heart against gravity.
Hepatopetal portal venous blood flow refers to the normal direction of blood flow within the portal vein, where blood is carried from the gastrointestinal tract and spleen to the liver. This flow is essential for delivering nutrients and metabolites for processing and detoxification by the liver. Any disruption or reversal of this flow can indicate underlying liver disease or portal hypertension.
Hypovolemic shock markedly decreases total liver blood flow by a reduction in portal venous blood flow.
Venous
Venous
Arterial blood flow is pulsatile due to the contraction of the heart, which produces pressure waves that cause the arteries to expand and contract rhythmically. In contrast, venous flow is more constant and steady because veins have one-way valves that prevent backflow and the pressure in the venous system is lower compared to the arteries.