3.8 : 触觉和化学感觉

The tactile sense is a sense of touch that can recognize sensations such as pressure, temperature, or pain through specialized receptors in the skin.

For example, when touching a friend's hand, touch receptors detect pressure on the skin. These signals travel through the sensory fibers originating from these skin receptors, through the brain stem and thalamus, and finally reach the cerebral cortex for touch perception.

Temperature changes at or near the skin activate thermoreceptors, the sensory nerve endings under the skin, helping to maintain the body's temperature at 98.6 degrees Fahrenheit.

Pain serves as a warning sign of bodily damage. Intense stimuli, such as sharp pinches, shift sensations from touch to pain by changing mechanical pressure sensations to pain.

The chemical senses include taste and smell.

Taste buds, located on the papillae of the tongue, contain receptors for various tastants, such as salt and sour, which integrate signals into taste perception.

Similarly, smell involves receptor cells in the nasal cavity's olfactory epithelium. These cells detect chemicals in the air and send sensory information to the olfactory regions within the temporal lobes for perception.