This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Heart, Circulation, and Blood, Subject name: Physiology
All are positive waves in JVP, except - 
Select and explain. 
A. a, B. c, C. v, D. x
D: x
Answer: D: x 
Explanation: Ans. is 'd' i.e., x Jugular Venous Pulse a waveIt is the positive presystolic wave produced by right atrial contraction.x descenta wave is followed by the negative systolic wave the x ' descent.The x descent is produced due to atrial relaxation.The atrial relaxation is produced as a result of ventricular contraction.c waveThe x descent is interrupted by second positive wave the 'c' wave.It is produced by bulging of the tricuspid valve into the right atrium during R V isolvolumetric contraction.v waveIt is the positive systolic wave.It result from increase in the blood volume in the venacava during systole, when the tricuspid valve is closedV.y descentFollowing the "v wave " this is a negative descending limb referred to as they descent or diastolic collapsed.It is due to tricuspid valve opening and rapid inflow of blood into the right ventricle.So there are# Three visible major positive waves (a,c and v) and# Two negative waves (x and y).