Somatic sensations are detected by sensory input from the sensory receptors scattered throughout your body. They can be found in the skin, skeletal muscles, and the walls of some internal organs. Somatic sensations can include things like pain, touch, pressure, temperature, motion, et cetera.
Signals from sensory receptors will be sent to the somatosensory cortex, which is located in the cerebrum of the brain, more specifically the parietal lobe. Interneurons within the somatosensory cortex are associated with various parts of the body. These interneurons are organized and laid out like a map, and larger parts of the map are associated with more sensitive areas of the body because more sensitive areas of the body have more receptors.
Pain is an example of a somatic sensation. Pain is a perceived injury and, although it is not a pleasant thing to experience, pain is actually an important protective feature of our body. Pain warns us that we've experienced some sort of injury to our body and that we need to withdraw from the situation that's causing that injury before a further injury occurs.
As you pull your hand away, it's not allowing for any more damage to occur.
Visceral pain relates to internal organs and somatic pain relates to pain on the skin, skeletal muscles, joints, and tendons. Sometimes we perceive pain on our body's surface, even though the tissue damage is occurring in a visceral organ because the brain can't pinpoint the source of the pain. This is called referred pain.
EXAMPLEAn example of this is when a person has a heart attack, often they'll feel pain down their left arm. The body or the brain is not able to properly identify where that source of pain is coming from, so it will project it to another part of the body.
Phantom pain is when a person experiences pain in a missing limb; this is common among amputees. If a person has had their leg amputated, often they will say they can still experience pain in that missing limb even though it's not there anymore. This is something that's not really fully understood yet and requires more research.
When signals of pain reach the brain, the hypothalamus will send signals to release endorphins and enkephalins. Endorphins and enkephalins are natural opiates that reduce our ability to perceive pain.
They were scared, but they didn't feel any pain because endorphins and enkephalins were released that inhibited their ability to perceive that pain so that they could continue to swim and try to survive.
They could continue to function because if they were able to feel that pain, they would become incapacitated and would probably end up drowning.
Pain is not felt until after the stressful situation has ended. That's why some scientists think it's an evolutionary trait that has developed in order to allow a person to escape a stressful situation.
There are actually thousands of sensory receptors that are found in the skin that detect touch, pressure, cold, warmth, and pain. Different types of receptors can be found at different layers of skin and within different depths, depending on which type of sensation they are there to detect.
One type of receptor that can be found in the skin are thermoreceptors, which are used to detect temperature changes. There are a couple of different types of thermoreceptors, depending on which type of temperature they are detecting.
Free nerve endings are also found within the skin, but they're also found in other internal tissues. There are actually several different types of free nerve endings that can detect touch, pressure, heat, cold, or pain. Free nerve endings are very simple in structure and are the dendrites of sensory neurons. Nociceptors are examples of free nerve endings that specifically detect pain.
Encapsulated receptors are enclosed in a capsule of connective tissue or epithelial tissue.
EXAMPLEPacinian corpuscles detect deep pressure or vibrations. Merkel's discs are also encapsulated receptors that detect steady touch.
Then we also have other types of encapsulator receptors that detect light touch. So depending on the type of touch, we have different types of receptors that will interpret that information. There is also the case of becoming less aware of a stimulus with repeated exposure, which is called sensory adaptation.
Source: THIS WORK IS ADAPTED FROM SOPHIA AUTHOR AMANDA SODERLIND