a. How do you describe the pattern of distribution for touch receptors in the regions of the skin you tested? They are grouped in the same areas and widely spread. b. How does the concentration of touch receptors seem to vary from region to region? Some areas of the body have more touch receptors than others. For instance, the finger has thousands of touch receptors, while the lips have millions of nerve endings. Part C: 1. Record the two point threshold, in millimeters, for skin in each of the following regions: a. Fingertip b. Palm C. Back of hand d. Back of neck e. Forearm f. Leg
The Correct Answer and Explanation is :
Answer:
Part A: Pattern of Distribution for Touch Receptors
The pattern of distribution for touch receptors in the skin shows varying concentrations in different regions. The receptors are densely grouped in some areas (like the fingertips and lips), while they are more sparsely distributed in other areas (like the back or forearm). This clustering is linked to the need for sensitivity in specific areas of the body. For example, the fingertips and lips are essential for precise tasks like reading Braille or sensing texture and temperature, which explains their higher concentration of receptors. In contrast, less sensitive areas of the body like the forearm or back are not as finely tuned for such tasks, which is why they have fewer receptors.
Part B: Variation of Concentration of Touch Receptors
The concentration of touch receptors is not uniform across the body. Areas like the fingertips and lips have a significantly higher number of touch receptors compared to regions like the forearm or back. This distribution allows for heightened sensitivity in the areas that need it most. The fingertips have a high density of touch receptors because they are involved in tasks requiring fine motor skills, like typing, grasping, or feeling textures. Similarly, the lips are sensitive to help with actions like eating or speaking. On the other hand, the back and forearm, areas less involved in delicate tasks, have fewer touch receptors and are less sensitive.
Part C: Two-Point Thresholds
A two-point threshold is the minimum distance at which a person can perceive two distinct stimuli when two points are simultaneously applied to the skin. The threshold varies across different regions of the body, with sensitive areas having a smaller threshold (able to detect smaller distances between stimuli), and less sensitive areas having a larger threshold.
Here are the typical two-point threshold measurements for various regions:
- Fingertip: 2–3 mm
- Palm: 8–10 mm
- Back of hand: 10–15 mm
- Back of neck: 20–25 mm
- Forearm: 30–40 mm
- Leg: 35–40 mm
Explanation:
The variation in two-point thresholds is directly related to the density of touch receptors in different parts of the body. Regions like the fingertips have a very fine sense of touch due to the high density of mechanoreceptors (such as Merkel discs and Meissner corpuscles), which makes the two-point threshold very small. In contrast, areas with fewer touch receptors, like the back and legs, have higher thresholds because the stimuli need to be farther apart for the brain to detect them as two separate points. The ability to distinguish between two points is crucial for tasks like reading Braille (in the case of fingertips) or detecting objects by touch.
I will now generate a simple image to illustrate the two-point thresholds across these different body regions.
You’ve hit your daily maximum number of images. To ensure the best experience for everyone, we have rate limits in place. Please wait for the next day before generating more images. Your daily maximum will reset in 10 hours and 49 minutes.
If you need further assistance with explanations or details, feel free to ask!