The primitive experiences that the senses give.
A feeling or information about something which has been sensed by a sensory nerve and is passed to the brain.
One of the facilities by which information about the external environment is received and interpreted; there are five major senses: sight, hearing, smell, taste, and touch.
The power or process of receiving conscious sense impressions through direct stimulation of the body or through the sense organs. Sensation can refer to an immediate reaction to external stimulation of a sense organ. For example, when it snows in the winter, there is a sensation of cold. The five senses (taste, smell, touch, hearing, and vision) are also known as sensations.
The result of messages from the body’s sensory receptors registering in the brain as information about the environment. Messages from exteroceptors are interpreted as specific sensations (smell, taste, temperature, pain, etc.) in the conscious mind. Messages from interoceptors, however, rarely reach the consciousness to produce sensation.
An awareness of conditions inside or outside the body resulting from the stimulation of sensory receptors.
A sensation or perception (such as a sound, smell, touch, or hunger) that becomes consciously experienced. The senses serve as conduits of information about the external surroundings and the body’s internal condition to the central nervous system, which comprises the brain and spinal cord.
Data is gathered through countless receptors (specific nerve structures) distributed throughout the body, including the skin, muscles, joints, internal organs, blood vessel walls, and specialized sensory organs like the eye and inner ear.
Receptors are finely tuned to specific stimuli, such as a particular wavelength of light, molecules with a distinct shape, vibrations, or temperature. When activated, each receptor “fires” by transmitting an electrical signal.
Certain receptors are the endpoints (free nerve endings) of lengthy nerve cell fibers, while others are specialized cells that link with these fibers. When a receptor is activated, a signal travels along the corresponding nerve fiber to the spinal cord and/or brain. A portion of this information reaches the sensory cortex of the brain, resulting in conscious perception.
The senses of vision, hearing, taste, and smell are considered special senses. Receptor cells responsible for these senses are grouped into distinct organs: the retina in the eye, the auditory system in the ear, the taste buds on the tongue, and the olfactory organ in the nose. Information from these organs is transmitted directly to the brain through the cranial nerves. While a significant portion of this information is directed to the cerebral cortex, some is relayed to other brain regions as well (for instance, from the eyes to the cerebellum, where it contributes to balance maintenance).
These sensations encompass pain, temperature, pressure, and proprioception (position). Proprioception depends on receptors located in the muscles and joints to offer insights into the spatial orientation of body parts. Pain, being one of the most primal senses, serves to signal potential harm through receptors found on the skin’s surface and within the body.
Diverse kinds of receptors are present within the skin. Some are attuned to pressure, while others respond to hair movement or temperature shifts. These skin receptors consist of nerve fiber endings, either wrapped around hair roots, configured as discs, or enveloped by layered membranes forming structures resembling onions, known as Pacinian corpuscles. Various patterns of stimulation of these receptors elicit sensations like pain, tickling, gentle or strong pressure, and warmth or coldness. Specific regions of the skin, such as the lips, palms of the hands, and genital area, possess a notably high density of receptors.
The majority of signals from these receptors travel through cranial or spinal nerves and pathways within the brain or spinal cord, reaching the thalamus and subsequently two specific regions within the sensory cortex referred to as the somatosensory cortices. Sensations perceived at distinct points within these regions correspond to the body parts from which the signals originated. The cortex dedicates larger expanses to sensations originating from the particularly sensitive hands and lips compared to less receptive areas.