Intestinal absorption.

Date:
1974
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Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

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Credit

Intestinal absorption. Attribution-NonCommercial 4.0 International (CC BY-NC 4.0). Source: Wellcome Collection.

About this work

Description

Professor David Smyth, Professor of Physiology at the University of Sheffield discusses the physiology of the gut and the process of intestinal absorption. He shows, with reference to early experiments, how it was first discovered that the intestine was a living organ which could survive even when extracted from the body. Smyth then explains, using detailed graphs and diagrams, the complex way in which the intestine absorbs substances, such as glucose and amino acids, into the blood stream.

Publication/Creation

London : University of London Audio-Visual Centre, 1974.

Physical description

1 encoded moving image (40 min.) : sound, black and white.

Duration

00:40:20

Copyright note

University of London

Terms of use

Unrestricted
CC-BY-NC
Creative Commons Attribution-Non-Commercial 2.0 UK: England & Wales

Language note

In English

Creator/production credits

Presented by Professor David Smyth. Introduced by Dr Ian Gilliland. Produced by Peter Bowen. Directed by David Sharp. Made for British Postgraduate Medical Federation. Made by University of London Audio-Visual Centre, 1974.

Notes

This video is one of around 310 titles, originally broadcast on Channel 7 of the ILEA closed-circuit television network, given to Wellcome Trust from the University of London Audio-Visual Centre shortly after it closed in the late 1980s. Although some of these programmes might now seem rather out-dated, they probably represent the largest and most diversified body of medical video produced in any British university at this time, and give a comprehensive and fascinating view of the state of medical and surgical research and practice in the 1970s and 1980s, thus constituting a contemporary medical-historical archive of great interest. The lectures mostly take place in a small and intimate studio setting and are often face-to-face. The lecturers use a wide variety of resources to illustrate their points, including film clips, slides, graphs, animated diagrams, charts and tables as well as 3-dimensional models and display boards with movable pieces. Some of the lecturers are telegenic while some are clearly less comfortable about being recorded; all are experts in their field and show great enthusiasm to share both the latest research and the historical context of their specialist areas.

Contents

Segment 1 Dr Ian Gilliland introduces Professor David Smyth. Smyth begins with a joke about 'Smyth's Law' which states that if you think something is going to be easy either you'll be proved wrong or it will have been done before. He then explains how, in the 1940s, a new technique enabling the study of intestinal absorption was discovered, opening the way for many new experiments. The technique was one which produced a preparation of intestine which could show the act of absorbtion outside the body. Smyth refers to a diagram showing apparatus set up for observing the movements of intestinal muscle, then a diagram showing the absorptive function of the intestine. Time start: 00:00:00:00 Time end: 00:04:49:19 Length: 00:04:49:19
Segment 2 Smyth refers to experiments by Fisher and Parsons in which glucose was added to a section of intestine, thus demonstrating the intestine's capacity to transfer glucose. He then tells of an experiment by Dr Wiseman on the mucosal fluids of the intestinal wall; he shows a diagram differentiating in vivo from in vitro experiments on the intestine. Smyth describes the 'everted sac' technique, an in vitro preparation discovered by Drs Wilson and Wiseman in 1954. This technique involves removing an animal's intestine under anaesthesia, then everting it on a glass rod. Once everted, small sacs can be made of the intestine, each one can be filled with different substances and intestinal absorption measured. Time start: 00:04:49:19 Time end: 00:09:14:00 Length: 00:04:25:06
Segment 3 Smyth shows how the above experiments relate directly to the physiology of absorption. He shows diagrams and graphs illustrating various intestinal absorption processes, then turns to show how the above techniques can be used to study them. He begins with absorption kinetics and outlines two types: absorption kinetics and saturation kinetics. Diffusion kinetics relates to the rate of absorption in proportion to the concentration of the substance absorbed. Saturation kinetics is the study of the limit of absorption, of the point where the intestine is so saturated as to be unable to absorb further. Time start: 00:09:14:00 Time end: 00:15:20:14 Length: 00:06:06:14
Segment 4 Smyth shows graphs listing the rates of absorption of different substances in the intestine, including proteins and carbohydrates. He also talks about the absorption of water-based substances, using diagrams to show how they pass through cell membranes. Time start: 00:15:20:14 Time end: 00:21:00:00 Length: 00:05:40:09
Segment 5 Smyth discusses where the final stage of digestion takes place within the intestine. He shows, using illustrations of an experiment on a rat, that this happens in the epithelial cells of the intestine. He believes that this proves that the terminal stages of digestion take place intracellularly. Time start: 00:21:00:00 Time end: 00:25:00:00 Length: 00:04:00:00
Segment 6 Smyth turns to look at the electrical activity of the intestine. He shows the results of an experiment measuring the absorption of sodium and fluid by the intestine when the intestine is artificially stimulated by different levels of electrical volt. He then discusses the relationship between various substances and different electrical volts, using diagrams and graphs to illustrate his points. Time start: 00:25:00:00 Time end: 00:30:11:00 Length: 00:05:11:00
Segment 7 Smyth differentiates two important functions of cells during intestinal absorption: transfer and metabolism. Transfer is, he says, an energy requiring process while metabolism is an energy donating process. Smyth shows a diagram illustrating the passage through the intestine of energy user and energy donor substances. He then focuses specifically on the transfer and metabolism of galactose and shows a table listing different substances which affect galactose transfer. Time start: 00:30:11:00 Time end: 00:34:25:00 Length: 00:04:14:00
Segment 8 Smyth refers to an experiment by Diamond in which mannitol, a substance which the intestine cannot absorb, was placed in the intestine to see if it acted as a barrier to substances which would normally be absorbed intestinally. Smyth sums up the lecture by looking forward to the 'few million experiments' which will no doubt follow the discovery of the new technique for measuring intestinal absorption that he outlined at the start of the lecture. Time start: 00:34:25:00 Time end: 00:40:20:21 Length: 00:05:55:21

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