Question

Discuss the anatomical changes in movement from the moment of stimuli to initial actions

Answer 1

A stimulus causes a detectable change the physical or chemical structure of an organisms internal or external environment. The ability of an organism or organ to respond to external stimuli is called sensitivity. Receptors present in the body is responsible for this.

When a stimulus is perceived by a specific receptor the sensory neurons transmit information from sensory receptors to the central nervous system. Interneurons transmit information within the CNS.Motor neurons transmit information from the CNS to effectors in order to initiate a response.

stimulus starts a nerve impulse along the cell membrane of the neuron. It is done by pro ducing action potential. When a neuron is at rest, the inside of the cell membrane is electrically negative compared with outside. Due to stimulus the cell membrane open membrane channels and as a result positively charged ions enter in to the cell. This the cell becomes positively charged compared with the outside.Then other channels open and let positively charged particles out of the cell. As a result the membrane once again becomes negatively charged compared with the outside. This process continues along the axon. The axon terminals of the neuron passes this impulse to the neighbouring neuron. Like this the process continue till the body respond to that stimulus. Neurons do not touch each other. Neurons interact through synapses. Synapse is a junction within two nerve cells in which impulses are carried by a neurotransmitter. Organism have different receptors for different stimuli.