What causes an attached sensory neuron to send the signal toward the brain?

Answer 1

When a sensory neuron is attached to a sensory receptor, it responds to various stimuli in the environment, like touch, pressure, temperature, pain, or chemical changes. The stimulation of these sensory receptor cells generates electrical signals known as action potentials or nerve impulses. These impulses are generated when the specific sensory receptors detect changes or stimuli and undergo a process called transduction.

Transduction involves the conversion of physical or chemical stimuli into electrical signals. This occurs through the opening or closing of ion channels on the sensory receptor cell membrane. For instance, in touch receptors, when pressure is applied, mechanoreceptor channels open, allowing sodium ions to enter the cell. This leads to a change in the cell's membrane potential, causing depolarization and generating an electrical signal.

Once the electrical signal is generated in the sensory receptor cell, it is transferred to the attached sensory neuron. The electrical impulse travels down the axon of the sensory neuron as a series of depolarizations and repolarizations called action potentials. The transmission of the electrical signal along the sensory neuron is facilitated by the opening and closing of voltage-gated ion channels.

These action potentials propagate toward the brain due to the neuron's specialized structure and electrochemical properties. The depolarization of one region of the neuron triggers the opening of voltage-gated ion channels in the adjacent region, leading to the propagation of the electrical signal. This propagation is facilitated by the movement of ions (e.g., sodium and potassium) across the membrane of the neuron.

The sensory neuron's axon extends from the sensory receptor to the brain, where it terminates at specific regions called sensory nuclei or sensory processing centers. At these regions, the electrical signals are further transmitted and integrated with signals from other sensory neurons. Ultimately, this information is processed and interpreted by the brain, allowing for perception and appropriate responses to stimuli.