The four different types of general sensory receptors include mechanoreceptors, thermoreceptors, chemoreceptors and nociceptors. Mechanoreceptors, thermoreceptors and nociceptors are categorized as somatosensory receptors responsive to mechanical displacement, temperature and pain, respectively, while chemoreceptors respond to chemical stimuli. Receptors respond to multiple stimuli and are therefore categorized by their lowest threshold.Continue Reading
Mechanoreceptors respond to a wide array of external and internal stimuli, such as touch, pressure, stretching, movement, itching and vibration. They function by sending signals to the central nervous system when their membranes are displaced. These can be further grouped into three smaller categories by what causes their signal transmissions: position and velocity receptors, velocity receptors and transient receptors.
Thermoreceptors detect temperature within and outside of the body. Externally, warm receptors and cold receptors detect temperature increases and decreases within the range of 59 to 109 degrees Fahrenheit. Nociceptors recognize pain associated with extreme mechanical, temperature and chemical stimulation.
External chemoreceptors concern taste and smell, and internal chemoreceptors monitor blood chemistry in the carotid body, aorta and brainstem. Taste receptors in the taste buds and smell receptors in the olfactory epithelium are closely linked and activated by similar stimuli. Messages to the brain from internal chemoreceptors do not result in a conscious sensation.Learn more about Nerves
Phasic and tonic receptors are two types of endings of sensory nerve cells. Phasic receptors respond quickly to stimuli, while tonic receptors adapt more slowly and over a more sustained period of time.Full Answer >
Though there are over 10,000 specific types of neurons, the three general classifications are sensory neurons, motor neurons and interneurons. Sensory neurons send signals from outside the body into the central nervous system, motor neurons transmit signals to activate muscles and glands, and interneurons act as connectors between neurons.Full Answer >
The brain is made up largely of neurons, or nerve cells, blood vessels and glial cells. Glial cells create a supporting structure for the brain. The brain is about 60 percent fat.Full Answer >
The main senses that are dependent on chemoreceptors in humans and many other animals are taste and smell. Taste is the detection of certain chemical compounds from direct contact with substances, while smell is the detection of chemicals suspended in the fluid the organism occupies, whether that be water or air. In animals that breathe, internal chemoreceptors also monitor the blood levels of carbon dioxide and govern the breathing reflex.Full Answer >