Question

What are free nerve endings? What do they do? Where are they located?

Answer 1

Free nerve endings are a type of sensory receptors found throughout our body. They are the simplest and most common type of nerve endings responsible for detecting pain and temperature sensations. Unlike tactile corpuscles, free nerve endings are not encapsulated and are scattered throughout the skin, connective tissues, and organs. They are particularly concentrated in areas that are more sensitive to pain, such as the fingertips, soles of the feet, and the cornea of the eye. When these nerve endings are stimulated by things like heat, cold, or tissue damage, they send signals to our brain, allowing us to perceive pain or temperature changes.

Answer 2

Free nerve endings are unencapsulated sensory receptors found in the skin that respond to pain, temperature changes, and light touch. They relay sensory information to the somatosensory cortex via the central nervous system. A two-point discrimination test can be used to estimate the density of these receptors on different areas of the body.

Step-by-step explanation:

Free Nerve Endings

Free nerve endings are the most common type of unencapsulated sensory receptors found in the skin. They are the terminal parts of sensory neurons and lack any specialized structures for detecting sensory stimuli. Free nerve endings can sense a wide range of stimuli including pain (nociception), temperature variations (thermoception), and, to some extent, light touch.

Function and Location of Free Nerve Endings

These nerve endings serve critical functions in the sensory system of the body. They are responsible for conveying sensations of pain, which alerts the body to potential harm, as well as changes in temperature, which is essential for maintaining homeostasis. Free nerve endings are located throughout the body, including in the skin's dermis, as well as in other organs such as skeletal muscles, liver, and the hypothalamus. The sensory information they collect is transmitted to the central nervous system through pathways that involve the spinal cord, medulla, thalamus, and finally to the somatosensory cortex in the postcentral gyrus of the parietal lobe.

Receptor Density and Sensation Transmission

Understanding the receptor density in various areas of the body can be useful for learning about the sensitivity of those areas. For example, a two-point discrimination test can reveal how close together two points must be for a person to feel them as distinct. This test is a way to estimate the density and receptive fields of sensory receptors, including free nerve endings. Ultimately, sensations detected by receptors like free nerve endings are transmitted to the brain, allowing us to respond appropriately to our environment.