Sensory receptors exhibit specialized sensitivities and transduction mechanisms to detect particular physical stimuli relevant for perception and behavior [1][2][3]. For example, photoreceptors in the retina contain light-sensitive opsins that transduce light energy into electrical signals [3][4][6]. Rod photoreceptors detect dim light while cone photoreceptors enable color vision [4]. In the auditory system, hair cells in…
Cell Types
Glial cells
Besides neurons, the nervous system also consists of so-called glial cells. These cells are non-excitable, and play several roles. They are generally categorized as: Ependymal cells, which line the central cavities of the brain and the spinal column. They have microvilli and can be ciliated. The cilia of ependymal cells facilitate the flow of cerebrospinal…
Neurons
Neurons are excitable cells found throughout most of the body, and they interact with other neurons, glands, muscle tissue and the sensory apparatus. The human body contains an estimated 85 billion neurons. Each neuron is connected to one or more (up to several hundred thousand) other neurons via junctions called synaptic terminals, which act as…