Pacinian corpuscles are larger and fewer in number than Meissner’s corpuscles and are oval-cylindrical-shaped. They are on hair and hairless mammalian skin, viscera, joints, and the periosteum of bone. They are primarily responsible for sensitivity to vibration and pressure. Their endings of specialized nerves feel pain, itch, and tickle.
They are wrapped by a layer of connective tissue and encapsulated with myelinated nerve endings, surrounded by Schwann cells. Its capsule consists of 20-60 concentric lamellae, including fibroblasts and fibrous connective tissue, separated by gelatinous material, more than 95% of which is water. It presents a whorled pattern on micrographs.
Schwann cells are involved in many different peripheral nerve biology, such as the conduction of nerve development, regeneration, trophic support for neurons, production of the nerve, extracellular matrix, modulation of neuromuscular synaptic activity, and presentation of antigens of antigens to T-lymphocytes. Schwann cells form the myelin sheath and support nerve regeneration.
The vertebrate`s nervous system relies on the myelin sheath for insulation and decreasing membrane capacitance in the axon. Pacinian corpuscles can even sense vibrations centimeters away. Their optimal sensitivity is 256 Hz.
Three Different Types of Touch
A Light touch is protective because it keeps us safe and responds immediately. Light touch can include tickling, a mosquito, or a spider web. It also can be something hot or something that hurts like a thorn. The light touch pathway responds immediately, but the information is not specific.
Discriminative touch provides specific and detailed information about what you are touching or where. This pathway will tell the brain what touched the skin and how it felt. From a previous experience, the brain could figure out what it was and what to do about it. This pathway is vital for accurate and precise fine motor skills and motor planning or praxis development.
Touch pressure, or deep touch pressure is a firmer touch or a squeeze and works alongside the discriminative touch pathway. A good example is when you receive a hug. The discriminative touch pathway identifies where you are touched and how hard you are squeezed. This sensation is called touch pressure. Another example is if you wear tight pants or cover yourself with a heavy blanket.
Touch Sensitivity
Some people can be very sensitive to touch, while others are the opposite and do not feel much pain. Much depends on how well-nourished a person is or was as a growing child.
Dyspraxia (difficulty in performing coordinated movements) is often associated with a neurodevelopmental condition in children (developmental coordination disorder). A deficiency or imbalance in the essential fatty acids, especially omega-3, is a major cause of poor neurodevelopment. Environmental toxins or vaccines are other causes.
Touch is Vital for Babies and Growing Children
Touch is vital for a baby’s growth, nerve, brain, and motor development. The more a baby is soothed and pampered with touch, the better the child will grow and develop physically, mentally, and emotionally. In addition to growth and development, touching along with good nutrition is essential for a child’s motor skills and learning (e.g., holding a pencil, opening lunch boxes, doing up buttons, cutting with scissors, playing sports, etc.). Stay-at-home mothers are better able to provide more affectionate touching for their babies and growing children. Children of working mothers are often deprived of the vital sense of touch and do not grow or develop very well. This deprivation is also common in large families or war-torn areas.
Adults Also Need the Sense of Touch
Who does not love or feel the benefits of a big hug, a romantic touch, or a nice massage? Hugs can indicate support, comfort, emotional warmth, joy or happiness, and affection beyond words. Hugging and touching have many benefits. Studies have shown that 20-second or longer hugs increase oxytocin and reduce blood pressure.