Body Fluids and Circulation VSAQs. Flashcards
Write the differences between open and closed systems of circulation.
a) Open type: The blood flows from the heart into the arteries. The arteries open into large spaces called sinuses. From the sinuses, the blood is carried by the veins to the heart. There are no interconnecting vessels, the capillaries, between the arteries and veins.
b) Closed type: The blood flows through blood vessels. The blood flows from the arteries through small blood vessels called capillaries.
Sino-atrial node is called the pacemaker off our heart. Why?
Sino-atrial node is formed by cardiomyocytes. SA node has ability to generate action potentials without any external stimuli. Hence, it is called pacemaker node.
Name the valves that guard the left and right atrioventricular apertures in man?
a) Left atrioventricular aperture: Bicuspid valve (mitral valve)
b) Right atrioventricular aperture: Tricuspid valve.
Name the aortic arches arising from the ventricles of the heart of man.
a) from, left ventricle-(left) systemic arch.
b) form right ventricle- Pulmonary arch.
Name the heart sounds. When are they produced.
a) During ventricular systole, atrioventricular valves are closed causing the first heart sound lub.
b) During cardiac diastole, the semilunar valves at the bases of aortic arches are closed causing second heart sound dup.
Define cardiac cycle and cardiac output.
a) The cardiac events that occur form the beginning of one heartbeat to the beginning of the next constitute is known as Cardiac cycle.
b) The volume of blood pumped out by the heart form each ventricle per minute is termed as cardiac output.
What is meant by double circulation? what is its significance?
In one complete circuit in the body, the blood passes twice through the heart, once through right side and the other time through the left side. This type of circulation is known as double circulation. It involves pulmonary circulation and systemic circulation.
Why the arteries are more elastic than the veins?
a) The muscle layer of the wall of arteries is thick and has two elastic laminae, one on each side. Hence arteries are much elastic.
b) The muscle layer of wall of veins in thin and lacks elastic laminae.
