For example: a muscle contracting to move an arm muscle squeezing saliva from the salivary gland a gland releasing a hormone into the blood Receptors are connected to effectors as follows: Sensory receptors These detect the changes in the environment stimulus Sensory neurons Nerve cells that send a signal from the sensory receptors to the CNS CNS The central nervous system CNS , which is the brain and the spinal cord.
This coordinates a response and sends a signal down a motor neuron. Motor neurons Nerve cells that receive a signal from the CNS and transfer it to the effector Effectors The muscles or glands that produce a response to the stimulus.
Touch, temperature, pain. Chemicals in food and drink, for example. Chemicals in the air, for example. Sound, position of head. These detect the changes in the environment stimulus. Nerve cells that send a signal from the sensory receptors to the CNS. The central nervous system CNS , which is the brain and the spinal cord. Nerve cells that receive a signal from the CNS and transfer it to the effector.
Adequate stimulus can be used to classify sensory receptors. Somatic sensory receptors near the surface of the skin can usually be divided into two groups based on morphology:.
A tonic receptor is a sensory receptor that adapts slowly to a stimulus, while a phasic receptor is a sensory receptor that adapts rapidly to a stimulus. Learning Objectives Differentiate among the types of stimuli to which receptors respond. Key Points Chemoreceptors detect the presence of chemicals. Thermoreceptors detect changes in temperature. Mechanoreceptors detect mechanical forces. Photoreceptors detect light during vision. More specific examples of sensory receptors are baroreceptors, propioceptors, hygroreceptors, and osmoreceptors.
Sensory receptors perform countless functions in our bodies mediating vision, hearing, taste, touch, and more. Key Terms photoreceptor : A specialized neuron able to detect and react to light.
Question: What is the smallest detectible weight difference between a one-pound bag of rice and a larger bag? What is the smallest detectible difference between a pound bag and a larger bag?
In both cases, at what weights are the differences detected? This smallest detectible difference in stimuli is known as the just-noticeable difference JND.
You will be testing JND of different weights of rice in bags. Choose a convenient increment that is to be stepped through while testing. For example, you could choose 10 percent increments between one and two pounds 1. So, 20 pounds feels the same as 22 pounds or 23 pounds, but 20 pounds feels less than 24 pounds. Test the hypothesis: Enlist 24 participants, and split them into two groups of To set up the demonstration, assuming a 10 percent increment was selected, have the first group be the one-pound group.
As a counter-balancing measure against a systematic error, however, six of the first group will compare one pound to two pounds, and step down in weight 1. Apply the same principle to the pound group 20 to 40, 20 to 38, and so on, and 20 to 22, 20 to 24, and so on. Given the large difference between 20 and 40 pounds, you may wish to use 30 pounds as your larger weight. In any case, use two weights that are easily detectable as different.
Record the observations: Record the data in a table similar to the table below. Record a minus sign - for each participant that finds no difference. What about the pound group? Draw a conclusion: Did the data support the hypothesis? Are the final weights proportionally the same? If not, why not?
A sensory activation occurs when a physical or chemical stimulus is processed into a neural signal sensory transduction by a sensory receptor. Perception is an individual interpretation of a sensation and is a brain function. Humans have special senses: olfaction, gustation, equilibrium, and hearing, plus the general senses of somatosensation.
Sensory receptors are either specialized cells associated with sensory neurons or the specialized ends of sensory neurons that are a part of the peripheral nervous system, and they are used to receive information about the environment internal or external. Each sensory receptor is modified for the type of stimulus it detects.
For example, neither gustatory receptors nor auditory receptors are sensitive to light. All sensory signals, except those from the olfactory system, enter the central nervous system and are routed to the thalamus. When the sensory signal exits the thalamus, it is conducted to the specific area of the cortex dedicated to processing that particular sense. Skip to content Chapter Sensory Systems.
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