Final answer:
Having very little subcutaneous tissue, as seen in newborns and the elderly, leads to increased sensitivity to cold due to the lack of insulation and reduced capacity for thermogenesis. This condition raises the risk of hypothermia and cold-related injuries such as frostbite.
Step-by-step explanation:
Impact of Subcutaneous Tissue on Sensitivity to Cold
Subcutaneous tissue acts as an insulator, helping to retain body heat and protect against cold environments. In individuals such as newborns and the elderly, who have less subcutaneous tissue, there is reduced thermal insulation. Consequently, these individuals may have an increased sensitivity to cold because their bodies are less efficient at retaining heat. Thermoreception is a process where thermoreceptors respond to changes in temperature. Cold and warmth information is conveyed to the brain through pathways that include the spinal cord, thalamus, and the primary somatosensory cortex.
The lack of subcutaneous fat also impairs the body's response to cold. Without sufficient fat, there is a diminished capability for thermogenesis, which is heat production in response to cold, especially for the non-shivering type that involves increased metabolism in adipose tissue. Moreover, blood circulation to extremities reduces even further in the cold, increasing the risk of conditions such as frostbite, particularly in fingers and toes. The skin and peripheral tissues may become more susceptible to damage from cold due to diminished blood flow, which can have serious consequences, including tissue damage or gangrene, necessitating amputation.
Overall, with reduced subcutaneous tissue, there is an elevated risk of hypothermia and other cold-related injuries because the body lacks the natural insulation and thermogenic capacity to efficiently maintain an optimal core temperature in cold environments.