Physiology (Biology)
Synaptic Transmission 
This is a nice narrated animation that gives you a fairly comprehensive outline of synaptic transmission at the neuromuscular junction. It goes through the function of Ca channels, SNARE's, Acetylcholine and its esterase and a little on the end plate potential.
Fantastic shockwave animation of the heart as a pump 
This animation will take you through each of the different phases of cardiac contraction and relaxation. This includes Atrial systole -> isovolumetric ventricular contraction -> rapid ventricular ejection -> reduced ventricular ejection -> isovolumetric relaxation -> rapid...
Anatomy of the Ear : Auditory Transduction 
This was written under the video: "With exciting 3-D animation and a dramatic classical sound track, this 7-min. video takes us on a trip through the ear to vividly explain how we hear. Auditory Transduction is definitely best of breed on the topic. Brandon Pletsch has given permission to 3M to...
Animation Quiz 1 - Activation of Complement 
A very nice basic animation about complement activation. This will do well for a quick review of complement activation. Additionally this has a 5 question quiz to test yourself afterwards.
A video describing the classical complement system 
This is an excellent representation of the classical complement system. I think this is one of the more complete videos I have seen. The classical complement system is the last to be activated and starts with C1 being activated by IgM or IgG (needs two molecules of IgG within close proximity.)
3D animation of actin-myosin crossbridge 
A great animation showing the inner workings of the sacromere (functional unit of a muscle). Basically Ca++ binds to troponin which sits on tropomyosin. Troponin helps open the actin-myosin binding site. ATP bound myosin will then bind at which time Mg++ will activate the ATPase, turning ATP into...
A great narration of the Resting Membrane Potential 
I really liked this narration and animation of the Resting Membrane potential. Basically electrochemical equilibrium is reached because the force due to the gradient potential of K ions moving out of the cell through K channels is balanced by the electrostatic force caused by the K being drawn to...
Understanding electrotonic conduction, action potentials and saltatory conduction 
This video helped me to understand the physiological differences between electrotonic conduction and saltatory conduction. It is a fairly complete overview of the physiological workings of a neuron.
NMDA and AMPA Receptors 
This is a nice little animation on how NMDA and AMPA receptors are stimulated by glutamate. NMDA needs a stronger stimulus in order to remove the Mg lodged within it. This allows Ca to enter which has multiple secondary messanger functions.
The Action Potential - Animation 
Nice step by step animation of a action potential caused by a stimulus that depolerized the neuron past threshold. This one has a lot of good information and will definitely help you see it more clearly.
