The action research process is an interactive method of collecting information. In the field of education, action research is used quite often to explore new ways of teaching and interacting in the classroom.
Unlike arteries, veins contain valves that ensure blood flows in only one direction. (Arteries donât require valves because pressure from the heart is so strong that blood is only able to flow in one direction.) Valves also help blood travel back to the heart against the force of gravity.rteries carry oxygenated blood away from the heart. Theyâre tough on the outside but they contain a smooth interior layer of epithelial cells that allows blood to flow easily. Arteries also contain a strong, muscular middle layer that helps pump blood through the body.
The vertebral arteries can be variable in diameter. They should always demonstrate antegrade flow (toward the brain) and be low resistance similar to the ICA. Arrows indicate normal flow direction in the extra cerebrovascular circulation. Arrows indicate the flow direction in a right sided subclavian steal syndrome.ERTEBRAL ARTERIES. 1  Return to a longitudinal plane of the CCA and angle the beam postero-laterally to visualise the vertebral artery. 2  Ensure suitable PRF and gain for these smaller, deeper vessels. 3  Confirm the flow is antegrade i.e. towards the head - (normal) or retrograde (suggesting subclavian steal syndrome).