This is an open book examination. You may use your notes and any available printed material but do not consult staff members or other' students.
The exams are to be turned in by 5:00 p.m., March 18, 1966.
1. Nerve and skeletal muscle have many properties in common but are quite different in other respects. Set up a comparison emphasizing the similarities and differences and giving quantitative evidence where available. (A reference to your sources might be useful.)
2. Turn in for examination the plots you made as a class exercise of the derivatives of the action potential and label the axes quantitatively for whatever nerve you used. Specify the assumed dimensions and constants of the nerve. Remember to identify the transmembrane potential as a function of time, the corresponding membrane current density in specified units, the longitudinal current or current density (specify which, and the units), the energy expended (determine it for the cycle), and, the quantity of charge shifted at the surface of the membrane per unit area.
3. a) Make a short resume of the idea behind the notion of a transfer function and show how this is embodied in the theory of transfer impedance as it is used in eloctrocardiography.
b) From any convenient reference copy out a “lead I” electrocardiogram and a “lead II” and from these calculate a “lead III” picture and indicate any problems you have had making it fit with the illustration.
4. A cell suspension (perhaps unfertilized marine eggs) contains 4 x 10 to the fifth power cells per milliliter, all quite uniformly spherical and 100 microns in diameter. Assume that they are suspended in sea water of 40 millimhos/cm conductance and that they have an interior resistivity of 40 ohms cm. Calculate the resistivity of this cell suspension at a low C frequency, say 25 c.p.s., and at a very high frequency, say 10 mo/soc., utilizing what you know about the capacitance and resistance of typical cell membranes.