Nerves

Yes, neurons are the basic building blocks of the nervous system. They are specialized cells that process and transmit information through electrical and chemical signals. Neurons play a key role in functions such as sensation, movement, reflexes, and cognition.

It varies by the type of cells involved (for example, a typical synapse from a pyramidal cell in motor cortex to a spinal cord alpha-motorneuron is not the same size as a synapse from that alpha-motorneuron onto a muscle fibre). But as one example, these 1950s papers examining prototypical synapses with an electron microscope (see related links) found that the presynaptic and postsynaptic membranes were separated by about 100-200 angstroms (10-20 nm); they contain synaptic vesicles that are 200-500 angstroms (20-50 nm) in diameter. In Plate 10 of the second of these articles (on invertebrates), the synapse labelled Y has a contact area that is maybe 0.4 micrometres (400 nm) in length in this electron microscope cross-section (so if this were a cut through the middle of a circular synapse, that'd imply a synaptic area of just over one square micrometre - but this is quite variable.

Lipids are important components of nerve cell membranes and the myelin sheath that surrounds nerves. They help maintain the structure and function of nerve cells by providing insulation and facilitating the transmission of nerve impulses. Lipids also play a role in signaling pathways that are essential for nerve function.

Lower motor neurons have cell bodies located in the spinal cord or brainstem. They carry motor information from the central nervous system to the muscles, enabling voluntary muscle movement. Damage to lower motor neurons can result in muscle weakness, atrophy, and a loss of reflexes.

The human brain does not have nerves. Nerves are part of the peripheral nervous system, which includes nerves outside the brain and spinal cord. The brain itself is made up of neurons, glial cells, and other supporting structures.

Neurons are shaped like long thin cells with a cell body, dendrites that receive signals, and an axon that transmits signals to other neurons. They have a unique branching structure that allows them to communicate with other neurons in the nervous system.

Yes, ATP is essential for nerve impulse propagation. ATP is used to provide energy for the sodium-potassium pump in neurons, which helps maintain the resting membrane potential and repolarize the cell after an action potential. Without ATP, nerve cells would not be able to generate or conduct nerve impulses effectively.

This area is referred to as the synaptic cleft. This area is bound by the end of one neuron (the terminal bouton) and the post-synaptic membrane of the next neuron. When an action potential reaches the terminal bouton, Ca2+ influx triggers the release of neurotransmitters across the cleft, which bind to receptors on the post-synaptic membrane, allowing for an post-synaptic excitatory potential (PSEP) to be formed in the next neuron.

It receives impulses from other neurons, and then sends those nerve impulses to the body of the cell, where they are added together at the axon hillock, and if they provide a sufficient strength (voltage, potential), an action potential will fire in the output of the neuron, the axon.

A neuron consists of three major parts: The dendrites, cell body, and axon. Most, though not all, axons are covered with myelin sheath which is made up of glial cells. The ends of axons are further divided into axon terminals. The axon terminal of one neuron and the dendrites of another is separated by the synaptic cleft.

Nerves communicate at specialized cell junctions known as synapses. In response to some stimuli, in many cases an action potential, the pre-synaptic nerve releases signal molecules into the space between the two cells (the synaptic cleft). The signaling molecule is then bound by a receptor on the post-synaptic neuron.

In this fashion "instructions" can be communicated between neurons. Generally binding of the messenger signal leads to the opening of an ion channel in the post-synaptic nerve causing that nerve to either become more or less excited. In the case of more excited the post-synaptic neuron will approach being able to fire its own action potential if it is excited enough.

Another name for an efferent neuron is a motor neuron. These neurons carry signals from the central nervous system to muscles, glands, and other effector organs in the body, enabling them to respond to stimuli.

Criteria required identifying a substance as a neurotransmitter 1- ) Synthesis of the substance: • It is synthesized in the neuron • Some substances are synthesized from the Tryptophan • Rate limiting step in its synthesis • Enzymes required in the synthesis of that substance are themselves synthesized in the cell body of neuron ,then distributed throughout the neuron • Mainly found in the cell body and nerve terminal • These enzymes are stored in the presynaptic terminal of neuron, inside the synaptic vesicles. 2- ) Storage of that substance: • The neutransmitter is stored inside the synaptic vesicle of nerve terminal 3- ) Release of the neurotransmitter: • It is released from the nerve terminal usually through Ca++ dependent process following the stimulation of the nerve fiber by action potential. • Fusion of the synaptic vesicle with the nerve membrane releasing neurotransmitter outside the nerve fiber into the synaptic cleft. 4- ) Exogenous analogue (drug) of the neurotransmitter: • If drug analogue of the neurotransmitter is injected exogenously, it should mimic the same mechanism of action as done by the endogenously released neurotransmitter.

Type A neurons are a classification of neurons based on their conduction velocity and function. They are typically fast-conducting neurons responsible for transmitting signals quickly over long distances in the body. Type A neurons are further subdivided into categories based on the diameter of their axons and the presence or absence of myelin sheaths.

Dendrites are the neuron part that pick up signals from other neurons. They are branch-like structures that extend from the cell body and receive incoming signals in the form of neurotransmitters released by neighboring neurons. These signals are then integrated in the cell body and transmitted along the neuron for further processing.

neurotransmitters, which are chemical messengers that transmit signals between neurons. When a nerve impulse reaches the end of a neuron, it triggers the release of neurotransmitters into the synapse. These neurotransmitters then bind to receptors on the neighboring neuron, initiating a new nerve impulse to continue the signal transmission.

The neurotransmitter acetylcholine is released from neuron axon terminals and binds to nicotinic receptors on muscle cells, triggering muscle contraction.

The fastest neurons in the human body can communicate their messages at speeds up to 250 miles per hour (400 km/h). These neurons are part of the somatosensory system responsible for transmitting sensory information such as touch, pain, and temperature.

A neuron (or neurone) is an individual cell of the nervous system. Neurons communicate with one another and other tissues through long processes that extend from their cell bodies. There are different names for these processes; some are called dendrites, others are called axons. Often it is fine to be vague and just call them fibers.

Fibers of multiple neurons serving a similar function can come together and be wrapped up in a piece of connective tissue. These fibers and their surrounding connective tissue are called a nerve.

Neurons are formed during early development through a process called neurogenesis. Neural stem cells located in the brain divide and differentiate into neurons. This process involves the growth of axons and dendrites, as well as the establishment of connections with other neurons to form a functional neural network.

The dendritic tree (to bind neurotransmitters (NTs)), the soma (also referred to as the cell body), the axon hillock (where action-potentials initiate), the axon (propagates the electrical signal), and the axon terminal (release of neurotransmitters). The membrane properties are also different to the average cell because they contain receptors and a high density of ion channels. Inside the cell, NTs are synthesized and 'shipped' down the axon to the axon terminal on long thin filaments propelled by tiny actin/dynein 'motors'. Once at the terminal, the NTs wait at the 'presynaptic active zone' for release (which is prompted by the electrical signal conveyed down the axon from the axon hillock).

The threshold potential must be reached for the neuron to fire. This is the level of depolarization that triggers an action potential to be generated and propagated along the neuron.

Efferent neurons are responsible for carrying signals away from the central nervous system to muscles or glands. They are involved in transmitting motor commands from the brain to the muscles to produce movement, rather than acting as the primary connector between other neurons.

The opening of voltage-gated sodium channels in response to a stimulus. Sodium ions flow into the cell, causing depolarization as the inside becomes more positively charged.