Hi Ragdolls! Thanks for joining atarnotes! Its great youre posting questions!
(I just lost all of this work that I was just about to post so bear with me if i cut things short)
Lets start with the ECG.
I'll use the terms depolarisation (meaning contracting/contraction) and repolarisation (meaning relaxing/relaxation) as these are the terminology that youll be wanting to use in your response to wow the marker
Point P represents the contraction (depolarisation) of the atria (note: plural of atrium, they are in sync)
Points Q, R and S (QRS complex) represents the simultaneous depolarisation of the ventricles and the repolarisation of the atria. It is important to note how fast this complex works. Anything considers above 0.11 seconds is considered abnormal, with 0.08-0.09 seconds considered average.
Point T represents the repolarisation of the ventricles
Point U (I only put this in as it is in some textbooks and so you might get a question on it, but I wouldnt exactly stress this) is simply the resting stage between points P and U, where neither atrium or ventricle is depolarisating or repolarising.
I'll post this before I lose it again and i hope this helps