Animal Physiology Lab Report

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03 - 03 - 2006 RESULT The amount of neural discharge due to stimulation of tactile sensilla receptor is posted on figure 1. FIGURE 1: Mean action potential activity of tactile sensilla receptors in femural of cockroach. In this experiment, it was found that there exists a spontaneous resting activity within the cockroach tibia even though tactile sensilla receptors have not yet been stimulated. From figure 1 it can be observed that the mean spontaneous resting activity of the cockroach leg is (42+/-9.7) action potentials/sec. After the tactile sensilla receptors were stimulated by moving the receptor with and against direction of growth there was an increase of action potentials. From figure 1 it can be seen that tactile sensilla…show more content…
Cockroach femoral tactile spine is a type I mechanoreceptors and it contains a single bipolar sensory neuron. At the base of the tactile spine, there are afferent neural sensory dendrites which are sensitive to signals. These dendrite in the wall of the spine leads through the spine lumen to a cell body, and then to an axon that proceeds along the femur. One interesting point is that the cell body is surrounded by glial cell however there is no glial cell wrapped around axon body or dendrites. The location of glial wrapping can suggest that they assist in passive conduction action potential from dendrites to the axon. (French 1993). Originally the dendrites are surrounded by fluid called endolymph which is rich in K+. When there is no stimulation there are few movement of ions in and out of the dendrites, this is can be seen in figure 1 as resting spontaneous potential activity. When there is a movement in tactile receptors bristle, the K+ channels open. Due to different concentration of K+ ions across the cell membrane, K+ ions enter the cell, causing the cell to depolarize. These causes increase in neural discharge resulting in increase in number of action potential. (Moyes & Schulte 2006).Depending on which direction the bristle moves, more or less K+ channel opens and therefore result in different amounts of action potential discharge as seen in figure 1. Sensory neurons associated with peripheral sensory structures, tactile

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