10:58duration 10 minutes 58 seconds
Ch 21 IX - Big Picture
Ch 21 objectives 12-34.
05:28duration 5 minutes 28 seconds
Ch 21 VIII - CD4 and CD8 Cells
Ch 21 objectives 32-33.
15:00duration 15 minutes 0 seconds
Ch 21 VI - MHC Molecules
Ch 21 objectives 29-30.