Description: Segment 1 Gilliland introduces Dowling. Dowling shows some gallstones which he holds in the palm of his hand. He discusses a diagram showing an illustration of the formation of gallstones. Time start: 00:00:00:00 Time end: 00:05:05:00 Length: 00:05:05:00 Segment 2 Dowling shows a series of slides illustrating different kinds of gallstones. He then shows a scanning electron micrograph of cholesterol gallstones, a micrograph of dust on the surface of a gallstone, a micrograph of melting crystals and a light micrograph of bile. Time start: 00:05:05:00 Time end: 00:10:29:00 Length: 00:05:24:00 Segment 3 Dowling discusses phospholipid molecules and shows a diagram illustrating the bilayered structure of hydrated phospholipid molecules. He then moves on to discuss bile salt molecules. Time start: 00:10:29:00 Time end: 00:15:06:00 Length: 00:04:37:00 Segment 4 Dowling shows a diagram illustrating the molecular structure of the sodium salt of a fatty acid. A further slide shows the molecular structure of sodium salt of cholic acid. This is also demonstrated as a 3D model. Time start: 00:15:06:00 Time end: 00:21:05:10 Length: 00:05:59:10 Segment 6 Dowling talks about how bile salts move through the body. He describes the relationship between beiliar cholesterol secretion an dbiliary bile acid secretion. Time start: 00:25:49:17 Time end: 00:30:03:00 Length: 00:04:13:08. Segment 7 Dowling talks about the cholesterol in bile salts, focusing on how the measurements of these differ in patients with gallstones. He shows various graphs and charts. Time start: 00:30:03:00 Time end: 00:34:54:00 Length: 00:04:51:00. Segment 8 Dowling summarises the lecture by going back over the primary and secondary abnormalities that lead to gallstone formation. Time start: 00:34:54:00 Time end: 00:41:55:24 Length: 00:07:01:24