Synonym nerve cells, neurons, lat. : nerve, -i Definition Neurons are nerve cells and therefore part of the nervous system. They serve the Recording, Processing and Forwarding of information. A nerve cell consists of a cell body (perikaryon or soma) and extensions. There are two types of extensions: Dendrites and Axons. Physiology Information is transmitted … Nerves
Excitation line In order for the information to spread along the nerve cell and be transmitted over long distances, action potentials must be generated along the nerve again and again. Two forms of excitation conduction can be distinguished: In saltatory conduction, parts of the nerve are so well isolated in regular sections that the excitation … Excitation line | Nerves
Central and peripheral nerves A distinction is made between a central nervous system (CNS) and a peripheral nervous system (PNS) and thus also between central and peripheral nerve cells. The nerve cells of the CNS include, for example, the motoneurons, which are found in both the brain and the spinal cord. In terms of numbers, … Central and peripheral nerves | Nerves
What is the patellar tendon reflex? The patellar tendon reflex (PSR) or “knee-cap reflex” is a reflex of its own that is frequently used in everyday clinical practice. This reflex is triggered by a light blow with the reflex hammer on the ligamentum patellae, a broad and strong ligament just below the patella, which represents … Patellar Tendon Reflex
Segments of the spinal column In humans, the sensitive neurons (afferences) move to the lumbar segments (lumbar vertebrae) L2-L4, in smaller animals to L3-L6. There the excitation is switched to the motor neurons (efferences) via one synapse each. These neurons pass through the plexus lumbalis and back to the muscle in the femoral nerve, where … Segments of the spinal column | Patellar Tendon Reflex
Definition – What is a neurotransmitter? The human brain consists of an almost unimaginable number of cells. An estimated 100 billion neurons, which carry out the actual thinking work, and once again the same number of so-called glial cells, which support the neurons in their work, form the organ that makes us humans something special … Neurotransmitter
GABA The amino acid glutamate is known to most people as a food additive and flavor enhancer in a variety of ready meals. However, glutamate is much more important for us as the most important excitatory neurotransmitter in our nervous system. In a way, glutamate is therefore the antagonist of GABA. However, the two messenger … GABA | Neurotransmitter
Serotonin Serotonin, also called enteramine, is a so-called biogenic amine, which is both a hormone and a neurotransmitter. As such, it plays an important role in the central nervous system as well as in the nervous system of the intestine and in its function as a hormone in the cardiovascular system. Its name is derived … Serotonin | Neurotransmitter
Simplified pictorial representation For better understanding the following illustration: A group of hikers (=action potentials) wants to cross a river (=synaptic cleft) with boats (=synaptic vesicles), but there is only one docking and undocking point per side (=pre- & postsynaptic membrane). If they have successfully crossed the flow, they can continue their migration on the … Simplified pictorial representation | Synaptic cleft
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
What is that? /Definition Acetylcholine is one of the most important neurotransmitters both in humans and in many other organisms. In fact, acetylcholine already occurs in unicellular organisms and is considered to be a very old substance in the history of development. At the same time, it is the longest known neurotransmitter (it was first … Acetylcholine
