Question
To increase the ability to absorb oxygen at its surface, red blood cells are spherical and covered with microvilli. To help allow blood flow back to the heart, veins have valves and veins also rely on the activity of skeletal muscles in close proximity to help move the blood in the right direction. Which statement is NOT accurate regarding the clotting cascade, and other responses by the body to minimize damage when blood vessels are damaged? when blood is exposed to damaged blood vessels, platelets, which are cell fragments derived from large known as megakaryocytes, stick to the damaged areas & form a plug the only way the clotting cascade can be activated is by certain clotting factors being exposed to the endothelial lining of blood vessels two "nutrients" that are needed for the clotting cascade to occur are the element calcium and the vitamin K damaged blood vessels undergo vascular spasm to minimize loss of blood from the blood vessels the critical event in the formation of a blood clot is the change of thrombinogen into thrombin which convert fibrinogen into fibrin The visceral pericardium is the same as the: mediastinum parietal pericardium epicardium myocardium endocardium Most of the middle layer in the heart wall is composed of: smooth muscle cells chondrocytes epitheliocytes fibrocytes cardiac muscle cells Blood returning to the heart from the systematic circuit first enters the: right atrium right ventricle left atrium left ventricle The normal pacemaker of the heart is located in the: Purkinje fibers ventricular muscle atrioventricular (AV) node sinoatrial (SA) node
Explanation / Answer
8) Red blood cells help in the transport of oxygen. They are biconcave and disc like structures. This disc shape increases their surface area-to-volume ratio which helps to increase the availability of oxygen at its surface. Therefore, the statement given in question is false.
9) Veins transport blood to heart against gravity. They contain valves to prevent back flow of blood. Skeletal muscle contractions also aid in venous flow of blood. Varicose veins will occur due to incompetance in venous valves. Therefore, the statement given in question is true.
