Nervous system what is a stimulus

A second way in which intensity is encoded is by the number of receptors activated. An intense stimulus might initiate action potentials in a large number of adjacent receptors, while a less intense stimulus might stimulate fewer receptors. Integration of sensory information begins as soon as the information is received in the central nervous system. Although perception relies on the activation of sensory receptors, perception happens, not at the level of the sensory receptor, but at the brain level.

The brain distinguishes sensory stimuli through a sensory pathway: action potentials from sensory receptors travel along neurons that are dedicated to a particular stimulus. All sensory signals, except those from the olfactory system, are transmitted though the central nervous system: they are routed to the thalamus and to the appropriate region of the cortex.

The thalamus is a structure in the forebrain that serves as a clearinghouse and relay station for sensory as well as motor signals. When the sensory signal exits the thalamus, it is conducted to the specific area of the cortex dedicated to processing that particular sense. Sensation processing : The brain has dedicated areas to the processing of stimuli, including: a thalamus and b the auditory, visual and somatosensory processing regions.

Privacy Policy. Skip to main content. Sensory Systems. Search for:. Sensory Processes. Reception Reception is the first step in the processing of sensation and is dependent on the receptor type, stimulus, and receptive field.

Learning Objectives Explain the process of sensory reception. Key Takeaways Key Points Reception is the process of activating a sensory receptor by a stimuli. Sensory transduction is the process of converting that sensory signal to an electrical signal in the sensory neuron. The process of reception is dependent on the stimuli itself, the type of receptor, receptor specificity, and the receptive field, which can vary depending on the receptor type.

Key Terms somatosensation : general senses which respond to stimuli like temperature, pain, pressure, and vibration reception : the act or ability to receive signals from stimuli. Transduction and Perception Transduction is the process that converts a sensory signal to an electrical signal to be processed in a specialized area in the brain. Learning Objectives Explain how stimuli are converted to signals that are carried to the central nervous system.

Key Takeaways Key Points Sensory signals are converted to electrical signals via depolarization of sensory neuron membranes upon stimulus of the receptor, which causes opening of gated ion channels that cause the membrane potential to reach its threshold. The receptor potentials are classified as graded potentials; the magnitude of these potentials is dependent on the strength of the stimulus.

The sensory system shows receptor specificity; although stimuli can be combined in processing regions of the brain, a specific receptor will only be activated by its specific stimulus. The four major components of encoding and transmitting sensory information include: the type of stimulus, the stimulus location within the receptive field, the duration, and the intensity of the stimulus.

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Sidebar [Skip]. This diagram summarises how information flows from receptors to effectors in the nervous system. Receptors to effectors The diagram summarises how information flows from receptors to effectors in the nervous system.

Receptors Receptors are groups of specialised cells. Sense organ Stimulus Skin Touch, temperature Tongue Chemicals in food and drink, for example Nose Chemicals in the air, for example Eye Light Ear Sound Effectors Effectors are parts of the body - such as muscles and glands - that produce a response to a detected stimulus.