The eighth nerve is the nerve of hearing and equilibrium. All of its receptive functions are accomplished by variations on a common theme; the different sensory information carried by different fibers in the nerve is simply the result of slight…
The Perception of Flavor Involves Gustatory, Olfactory, Trigeminal, and Other Inputs When we eat food or drink a beverage, we have a unified perception, centered on the tongue, of some mixture of flavors. However, this unified perception actually results from…
Cranial nerves and their central connections often look bewilderingly complicated, but for the most part they are actually arranged systematically. Cranial Nerve Nuclei Have a Generally Predictable Arrangement Key Concept The sulcus limitans intervenes between motor and sensory nuclei of…
The Brainstem Has Conduit, Cranial Nerve, and Integrative Functions The brainstem is another part of the CNS whose importance is out of proportion to its size. All of the long tracts traverse the brainstem on their way to or from…
The spinal cord is pretty small, but its importance is out of proportion to its size. It's the home of all the motor neurons that work your body, and of a large percentage of the autonomic motor neurons as well.…
Neural traffic to and from the CNS travels in peripheral nerves . The afferent fibers in these peripheral nerves either have endings that respond to physical stimuli (making them primary afferents that are also sensory receptors ) or carry information…
In contrast to the way in which information travels within individual neurons as electrical signals, information is usually transmitted between neurons through the release of neurotransmitters at specialized junctions called synapses . And in contrast to unvarying, always-depolarizing action potentials,…
Neurons share many properties with other cells, including their complement of organelles, an electrical potential across their surface membranes, and an ability to secrete various substances. What distinguishes neurons is the ways in which they have adapted these common properties…
The central nervous system (CNS) is tremendously active metabolically—relative to its weight, it uses much more than its share of the available oxygen and glucose. Corresponding to this metabolic activity, it has an abundant and closely regulated arterial supply and…
The ventricular system , the remnant of the space in the middle of the embryonic neural tube (see Fig. 2.5 ), is an interconnected series of cavities that extends through most of the central nervous system (CNS). The Brain Contains…