Neurite is the term used to describe the cell extension of a nerve cell through which electrical impulses are transmitted to its environment. If the neurite is also surrounded by “glial cells” that isolate it, it is called an axon. Function and structure A neurite is the extension of a nerve cell, and directs its … Neurite
A Ranvier lacing ring is a ring-shaped interruption of the fat or myelin sheath surrounding nerve fibers. In the course of “saltatoric excitation conduction” it serves to increase the speed of nerve conduction. Saltatoric, from Latin: saltare = to jump refers to the “jump” of an action potential that takes place when it encounters a … Ranvier lacing ring
Definition Dendrites are the cytoplasmic extensions of a nerve cell, which usually branch off from the nerve cell body (soma) in a knot-like manner and become more and more finely branched in two parts. They serve to receive electrical stimuli from upstream nerve cells via synapses and transmit them to the soma. The dendrites also … Dendrit
Spinous processes Dendrites that do not have a spinous process are called “smooth” dendrites. They pick up nerve impulses directly. While the dendrites have the spines, the nerve impulses can be absorbed through the spines as well as through the dendrite trunk. The thorns emerge from the dendrites like little mushroom heads. They can increase … Spinous processes | Dendrit
Motoneurons are the nerve cells responsible for the formation and coordination of movements. According to the location of the motoneurons, a distinction is made between the “upper motoneurons”, which are located in the cerebral cortex, and the “lower motoneurons”, which are located in the spinal cord. The lower motor neuron The lower motoneuron is located … Motor neuron
A nerve fiber is a portion of a nerve. A nerve is composed of several nerve fiber bundles. These nerve fiber bundles contain many nerve fibers. Each nerve fiber is surrounded by the so-called endoneurium, a kind of protective mantle around each nerve fiber. The endoneurium consists of connective tissue and elastic fibres and because … Nerve fiber
Markless nerve fibers Markless nerve fibers can be found mainly where information does not have to be passed on so quickly. For example, pain nerve fibers that transmit information about pain sensation to the brain are partially markless. This is important because, for example, there is pain that has to last a long time. In … Markless nerve fibers | Nerve fiber
Nerve fiber quality Nerve fiber quality is used to describe from which part of the body information is passed on. On the one hand, there are the somatosensory nerve fibers, which are also called somatoafferent. Somato refers here to the body, sensitive or afferent, refers to the fact that the information is transmitted from the … Nerve fiber quality | Nerve fiber
Synonyms nerve impulse, excitation potential, spike, excitation wave, action potential, electrical excitation Definition The action potential is a short change of the membrane potential of a cell from its rest potential. It is used to transmit electrical excitation and is therefore elementary for the transmission of stimuli. Physiology To understand the action potential, one must … Action potential
Action potential at the heart The basis of electrical excitation of the heart is the so-called action potential. It represents the biologically temporally limited change of an electrical voltage across the cell membrane, which ends in a muscle action, in this case the heartbeat. With a duration of about 200 to 400 milliseconds depending on … Action potential at the heart | Action potential
Definition The synaptic gap is a space between two communicating nerve cells that plays an important role in the transmission of action potentials (nerve impulses). In it a modulation of signal transmission takes place, which has a great pharmacological importance. Construction of a synaptic cleft A synapse is the transition between two nerve cells or … Synaptic cleft
Functionality of chemical synapses Whenever a nerve cell sends a signal to a muscle, gland or other nerve cell, the transmission takes place via the synaptic gap, which is only about 20-30 nanometers wide. The long extensions of the nerve cells (also called “axons”) conduct the nerve impulse (i.e. the “action potential“) from the center … Functionality of chemical synapses | Synaptic cleft