Film: 9498

Science | 1940 | Sound | Colour

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Synopsis:

This film shows a cat being subjected to three experiments almost simultaneously Use of animals in scientific research or vivisection 1940's to examine Sympathie impulses of the Humoral transmission, nerve impulses.


Title on screen: "Theory". A diagram of a nerve cell ending in the neighbourhood of a muscle cell. An animation describes humoral transmission of a nerve impulse. Another diagram describes how a nerve impulse arrives at the post ganglionic fibre of a blood vessel, "sympathine" is liberated and causes contraction of the muscle cells in the blood vessel wall. Two diagrams of nerve endings releasing "sympathine" to muscle cell, the "sympathine" that is released into the blood stream will cause an organ to be stimulated. A diagram illustrates an experiment which shows the release of sympathine from sympathetic nerve endings, synaptic nerves stimulate the supra renal gland which releases adrenaline which then stimulates a distant organ. After the removal of the supra renal gland and denervation of distant organ, the distant organ can still be stimulated through the release of sympathine into the blood stream. Title on screen: "Removal of the superior cervical ganglion". Detailed close up of the superior cervical ganglion being surgically removed from the cat. Close up of the skin being sewn up, the cat is left for a week to recover. Close up of the cat awakening from the anaesthesia, can see stitches on its neck. Title on screen: "Effect of adrenaline on the nictitating membranes, normal and denervated". The anaesthetised cat is sprawled on an operating table. Close up of the cat's face reveals that the right eye is highly dilated, the left eye is normal. A thread is passed through the nictitating membrane of each eye. The cat undergoes an experiment which shows the effects of adrenaline on the normal and denervated nictitating membranes (it all appears quite cruel even though the cat is anaesthetised). Adrenaline is injected into the femoral vein, a smoke drum measures the effects of adrenaline on the nictitating membranes, this experiment demonstrates that structures that are denervated are more sensitive to adrenaline. Title on screen "Stimulation of the Splanchic nerves". The cat's abdomen is opened by a mid-line incision. Close up of the open abdominal wall, close up of the splanchic nerve, the splanchic nerve is dissected. The splanchic nerve is cut in half, each half is placed on stimulating electrodes, stimulation is applied to the splanchic nerve and the results are recorded on the smoke drum. An increase in blood pressure is observed, this is due to contraction of the blood vessels in the splanchic area, and to the release of adrenaline from the supra renal gland. The denervated membrane is contracted in parallel to the increase in blood pressure, no contraction of normal nictitating membranes. After adrenaline is injected, normal nictitating membranes contracted to half the height of denervated membranes. Title on screen: "Removal of the supra renal glands". Close up of the cat's supra renal glands being removed. Close up of the removed glands. Electrodes are applied to the splanchic nerve, stimulation produces a rise in blood pressure, after a while the denervated membrane contracts, no change was observed in the normal membrane. View of the smoke drum displaying the nerve stimulation results from the three experiments.

13ft Sympathin released from nerve endimgs causes contraction of muscles in blood vessel walls and in viscera. It also has effects on remote organs
117ft Superior cervical ganglion removed from an anaesthetised cat
208ft The effect of adrenaline on the nictitating membrane is demonstrated on the cat, with traces on a smoked drum
310ft The effect of stimulating the splanchnic nerves is shown on the drum
435ft The suprarenal glands are removed and the experiment repeated


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