The same principle can be applied to the 20-pound group (20 to 40, 20 to 38, and so on, and 20 to 22, 20 to 24, and so on).
You may want to use 30 pounds as your larger weight because of the large difference between 20 and 40 pounds.
You can use two weights that are different.
For the one-pound and 20-pound groups, record a plus sign for each participant that finds a difference between the base weight and the step weight.
For each participant, record a minus sign.
If one-tenth steps were not used, replace the steps in the "Step Weight" columns with the steps you are using.
Weber's Law states that a just-noticeable difference in aStimulus is proportional to the magnitude of the originalStimulus
By the end of this section, you will be able to explain why the perception of pain is subjective.
The sense of touch is also known as somatosensation.
There is somatosensation all over the body and at some interior locations.
A variety of receptor types are found in the skin, muscles, joints, internal organs, and cardiovascular system.
The outermost layer of skin in mammals is the epidermis.
It is very thin and has no blood supply.
The thicker dermis contains blood vessels, sweat glands, hair follicles, lymph vessels, and sebaceous glands.
The hypodermis is the layer of tissue below the skin and contains blood vessels and nerves.
The hypodermis is the part of the body that holds 50 percent of the fat.
The skin of mammals has three layers.
There are five types of sensoryreceptors: mechanoreceptors, thermoreceptors, proprioceptors, pain and chemoreceptors.
The nature of stimuli is what determines these categories.
Touch involves more than one kind of stimulation and more than one kind ofreceptor.
The skin's méntoreceptors are encapsulated or unencapsulated and include free nerve endings.
The most common nerve endings in the skin are free nerve endings.
To hot and cold, and to light touch, the free nerve endings are sensitive.
They are not as sensitive to sudden changes in stimulation.
Tactile, proprioceptors, and baroreceptors are three different classes of mechanoreceptors.
The ménoreceptors sense stimuli due to the physical changes of their plasma membranes.
Two of the four primary touch points are on the surface of the skin and the other two are deeper.
The Krause end bulbs are only found in specialized regions.
The disks are spread out in the fingers and lips.
They respond to light touch with slow adaptation and encapsulated nerve endings.
Light touch, also known as discriminative touch, is a light pressure that allows a location to be pinpointed.
The fields of the disks are small.
They come into use in tasks such as typing on a keyboard because they are sensitive to edges.
There are four primary mechanoreceptors in human skin.
The unencapsulated disks respond to light touch.
All of the end bulbs are encapsulated.
The corpuscles respond to touch and low frequencies.
The ruffini endings detect stretch.
Transient pressure and high-frequency vibration can be detected by the corporacles.
They are found mostly on the fingertips and eyelids.
They respond to touch and pressure in different ways.
They are rapidly adapting, fluid-filled, encapsulated neurons with small, well-defined borders and are responsive to fine details.
Like the disks, the corpuscles in the palms are not as plentiful as they are in the fingertips.
The bright field light allows for touch discrimination of fine detail.
They are found on both sides of the body.
These are slow-adapting, encapsulated mechanoreceptors that detect skin stretch and deformations within joints, so they give valuable feedback for gripping objects and controlling finger position and movement.
They contribute to both proprioception and kinesthesia.
The ruffini endings detect warmth.
The warmth detectors are deeper in the skin than the cold detectors.
Humans detect cold stimuli before they detect warm stimuli.
They are quickly adapting the mechanoreceptors that sense pressure and high frequencies.
The internal dendrites of the pecinian receptors are stimulated by being compressed.
There are more endings in skin than in disks.
Using bright field light microscopy, the corpinians can detect pressure and high-frequency vibration.
proprioceptive and kinesthetic signals travel through myelinated afferent neurons.
There are "gaps" between communicating neurons, but they are not physically connected.
The signals continue to travel to the thalamus once in the medulla.
The signals from limbs are proprioceptive and kinesthetic.
The brain region that coordinates muscle contraction rather than the thalamus is what proprioceptive signals run from.
Pressure changes in an organ can be detected by baroreceptors.
They can be found in the walls of the arteries where they monitor blood pressure, and in the lungs where they detect lung expansion.
The stretch receptors are found in various parts of the body.
There are two types of deeper receptors that are found on nerve endings that wrap around the base of hair follicles.
Slow and rapid hair movement can be detected by a few types of hair receptors.
Some hair receptors can detect stimuli that have not yet touched the skin.
A very refined sense of touch is achieved by the configuration of the different types of receptors.
Near the surface, the nociceptive receptors are located.
The upper layers of the mechanoreceptors are whereMerkel's disks and Meissner's corpuscles are located.
The large mechanoreceptors are located in the lower layers and respond to deeper touch.
The primary somatosensory cortex and secondary cortical areas are responsible for processing the stimuli.
The distribution of touch receptors in the human body is not consistent.