To increase the ability to absorb oxygen at its surface, red blood cells are sph

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

Answer 8 . This is false. Red blood cells have biconcave or flat disk shaped that increase surface to volume ratio that help oxygen and carbondixide to diffuse across the plasma membrane of red blood cells. Red blood cells carry oxygen from lungs to tissue. RBCs lack the nucleus and contain iron rich protein hemoglobin which involve in gaseous exchange.Red blood cells have plasma membrane not microvilli.

Answer 10. when blood vessels is cut the first event is vascular spasm or vascular constriction to reduce blood flow through that area. After that platelets plug is formed by platelate adhere to and activated by collagen in blood vessel endothelium. If platelete plug is not enough to stop the blood then blood clot is formed. Platelets is stimulated to release substance that activate prothrombin into thrombin which further activate soluble plasma protein fibrinogen to convert into insoluble protein threads fibrin. Vitamin K is act as cofactor for an enzyme that help proteins to bind with calcium. This calcium binding is essential for activation of vitamin K dependent coagulation factor (prothrombin) and activation of clotting cascade event for blood clot formation. This description indicates that option a,c,d & e are correct . means here the answer is (b).Blood leaking from endothelium starts two events 1. change in platelets and interaction of tissue factor to plasma factor vii which leads to fibrin formation.

11. Visceral paracardium is same asthe epicardium answer is C. Epicardium is a thin layer of connctive tissue. Heart is covered with fibrinous sac called pericardium that divided in two layer, parietal and visceral along with pericardial space between them. heart is situated in the middle mediastenum. Muscles tissue of heart called myocardium forms a thick middle layer between outer epicardium and inner endocardium layer. A lining around the valve and chamber of the heart called endocardium.

12. The answer is cardiac muscles cells (e). middle layer of heart wall is called myocardium that made up of muscles tissue that is cardiac muscles cells that receive stimulation from sinoartrial and artrioventricular nodes.

14. Normal pacemaker of heart is located in sinoartrial node ans (d). THe heart rate is controlled by this node by sending elecrical signal to heart muscles to contract and circulation of blood throughout the body.

15. Blood leaves the right ventrical by passing throught the pulmonary valve (a). During blood circulation, blood enters into right artrium through veins , once it is fulled tricupsid valves open end blood enter into right ventrical and pressure changes in right artrium & ventrical, tricupsid valve become close. As right ventrical filled with desaturated blood pulmonary valve become open and blood pump through the pulmonary valve and into the lungs.

13. As mention in above answer blood returning to the heart from systemic circuit first enter into right artrium (a).

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