Final answer:
Some parts of the body are more sensitive than others primarily due to a higher density of nerve endings. Sensors like Meissner corpuscles and Pacinian corpuscles are more abundant in sensitive parts of the skin, such as the fingertips. Sensitive skin, often glabrous skin, is thicker and contains more touch receptors.
Step-by-step explanation:
The reason some parts of the body are more sensitive than others is mainly due to the density of nerve endings in the area. The skin acts as a sense organ because it contains specialized sensory nerve structures that detect touch, temperature, and pain. These sensory receptors are especially concentrated on sensitive areas, such as the fingertips. For instance, the Meissner corpuscles are responsible for sensing light touch, while Pacinian corpuscles detect vibration. These areas are sensitive not because the skin is thinner or because the dermis is closer to the epidermis, but because of the higher concentration of nerve endings.
Additionally, some sensitive areas of the skin are covered with glabrous skin, which is thicker and more sensitive than hairy skin, and has a higher density of touch receptors. The dermis layer, which contains many of these nerve endings, is a tough connective tissue that attaches to the epidermis by collagen fibers. It also includes blood vessels, sweat glands, and hair follicles, which contribute to the sensing functions of the skin.