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This programme illustrates sections of the text of Unit five and is divided into three parts. The speakers are Dr. Richard Holmes and Jeff Thomas, lecturers in Biology at the Open University. A spe...cial technique allowing microscopic examination of the capillaries in a rabbit's ear is shown and blood flow in capillaries, arterioles and venules is then examined microscopically. The response of these fine bloodvessels to priscol (a vaso-dilator) and privin (a vaso-constructor), is examined. The parasympathetic reflexes that regulate cardiac output in the mammal are then demonstrated on a decerebrate rabbit preparation, In the final part of the programme the mammalian double circulation is visualised by following the course of X-ray opaque material through the human heart and lungs, a sheep's heart is demonstrated, and the aortic semi-lunar valves are shown in action.
Metadata describing this Open University video programme
Module code and title: S22-, Comparative physiology
Item code: S22-; 05; 1972
Series: Comparative physiology
Episode 5
First transmission date: 18-03-1972
Published: 1972
Rights Statement: Rights owned or controlled by The Open University
Restrictions on use: This material can be used in accordance with The Open University conditions of use. A link to the conditions can be found at the bottom of all OUDA web pages.
Duration: 00:24:25
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Producer: Tony Laryea
Contributors: Richard Holmes; Jeff Thomas
Publisher: BBC Open University
Keyword(s): Arterioles; Blood flow; Capillaries; Cardiac output; Microscopic examination; Parasympathetic reflexes; Priscol; Privin; Rabbit's ear; Venules
Footage description: Shots of the vascular system of a human baby, a human brain, and a human heart. Jeff Thomas introduces the programme. He lists some physical dimensions of capillaries in humans (total length, volume, etc.) Shots of a technique for microscopic examination of capillaries in a rabbit ear. Commentary explains the procedure. Shots of blood passing through capillaries in a rabbit ear. Jeff Thomas begins discussion on control in the capillary system. He uses a model of a capillary section as an aid. Shots (under magnification) of blood moving in capillaries. Control changes can be seen - diameter of capillary is changed to reduce or increase blood flow. Effect of Priscol 10 on diameter of capillaries shown (dilate) Effect of Privin 10 on capillary diameter seen, (contract) Shot of capillary undergoing rythmic contractions. Their effect on blood flow velocity is seen. Jeff Thomas begins discussion on the effect of the nervous system on vascular flow. Effect of nerve stimulation on vascular flow in the rabbit's ear shown. Jeff Thomas introduces Dr. Richard Holmes. Holmes discusses the inhibitory mechanisms ofthe parasjm pathetic nervous system which "fine tunes" blood pressure in animals. He uses a diagram as an aid. He then introduces an experiment in which cardiac output through parasympathetic reflexes in mammals is demonstrated on a decerebrate rabbit. Film shots of the experiment. Impulses from the depresssr nerve are displayed on an oscilloscope. Adrenalin is injected into the blood system and its effect monitored. Shots of an experiment which monitors the effect of electric stimulation of depressant nerves on vascular pressure. Holmes explains an experiment which monitors the effect of vascular pressure decrease on nerve stimulation. He uses diagram to aid Shots of the experiment being performed. Holmes returns to his diagram to explain the results of this experiment. Further shots of the experiment. Holmes cuts the vagus nerve in his diagram. Shots of vagus nerve being cut on the rabbit. Effect of this on the heart is monitored. Cut ends of vagus nerves are stimulated and effect on the heart is monitored. Thomas with some sheep hearts, points out their major features. He then discusses the use of radio-opaque materials in the blood to visualize the working of the heart and lungs. Film shots of X-ray opaque, material treated blood moving through the heart. Thomas shows the aortic semi-lunar valves in a sheep heart which contribute to mammalian double circulation. Film sequence shows aortic semi lunar valves at work.
Master spool number: 6LT/70313
Production number: 00521_2123
Videofinder number: 3579
Available to public: no