The biology of the heart muscle.

Date:: 1977

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Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

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Credit

The biology of the heart muscle. Attribution-NonCommercial 4.0 International (CC BY-NC 4.0). Source: Wellcome Collection.

About this work

Description

PC Harris, Head of the Department of Cardiac Medicine Cardio-Thoracic Institute, talks about the biology of the heart muscle. A summary accompanying the cassette reads: "Contraction of the cardiac muscle is performed by the sliding movement of the filaments of the myofibrils. The energy for this purpose is provided by the hydrolysis of ATP. The mitochondria replenish the supply of ATP by oxidative phorylation. The presence of the sodium: potassium exchange pump in the cell wall membrane, together with the varying permeability of the membrane to different ions, leads to a resting transmembrane potential. During excitation the permeability of the membrane changes in a sequential fashion. The action of a number of cardio-active drugs may be explained in this region. The link between excitation and contraction is mediated by calcium ions which are alternately sequested and released by the sarco-plasmic reticulum." 6 segments.

Publication/Creation

London : University of London Audio-Visual Centre, 1977.

Physical description

1 encoded moving image (30.13 min.) : sound, color.

Series

The Scientific Basis of Medicine

Contributors

Harris, PC.

Duration

00:30:13

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 PC Harris, Head of the Department of Cardiac Medicine, Cardio-Thoracic Centre, University of London. Produced by David R Clark. Made by University of London Audio-Visual Centre. Made for British Postgraduate Medical Federation.

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.

Segment 1 Harris introduces the lecture and talks in particular about what is known about myocardial hypertrophy, the ill effects of ischaemia and the way antiarrhythmic drugs act. He shows a table listing the four main structures of the myocardial cell and shows an animated diagram which highlights its contractile structures. Time start: 00:00:00:00 Time end: 00:05:35:00 Length: 00:05:35:00

Segment 2 Harris talks about the provision of energy for heart muscle contraction and shows an animated diagram relating to this. Further graphs and diagrams show how the body uses hydrogen for energy. Time start: 00:05:35:00 Time end: 00:10:26:00 Length: 00:04:51:00

Segment 3 We are shown electron micrographs of mitochondria and then a film of an experiment using a mitochondrial suspension. A further animated diagram shows the function of the myocardial cell Time start: 00:10:26:00 Time end: 00:15:34:00 Length: 00:04:08:00

Segment 4 Harris refers to an animated electrical tracing of the action potential of cardiac muscle. Time start: 00:15:34:00 Time end: 00:19:10:00 Length: 00:03:36:00

Segment 5 Harris shows further electron micrographs detailing different aspects of cardiac musculature.He explains, using a short film sequence, how a spectrophotometer traces calcium ions and shows a further short film of an experiment to measures quantities of calcium ions. Time start: 00:19:10:00 Time end: 00:25:43:00 Length: 00:06:33:00

Segment 6 Harris continues to refer to the filmed experiment in which calcium ions are measured, then sums up the main points of the lecture. Time start: 00:25:43:00 Time end: 00:30:13:04 Length: 00:04:30:04