no spek eengish
the
The high-speed signals that pass along the axon are called action potentials. They spread in a wave of depolarization.
What they relay is whether of not they were 'on' or 'off' and how often; and this occurs as an action potential firing frequency. There is no message in the sense that neurons might pass on complex messages, like an email for instance; or store memories of events and facts. No one neuron can do anything like that. It takes many neurons working together to achieve this.
A nerve impulse travels toward the actual nucleus itself to pass information.
synapse
the olfactory (smell) and gustatory (taste) sensations pass along the cranial nerves directly to the brain. smell signals travel from the olfactory nerve (made up of groups of nerve fibres ) to a patch of the cortex located in the temporal lobe.
optic nerve
No, but a peripheral nerve does.
The high-speed signals that pass along the axon are called action potentials. They spread in a wave of depolarization.
An activated neuron will send an action potential from upper motor neurons to lower motor neurons to effector organs. It is able to propagate the action potential to the motor end plate by release of neurotransmitters, chiefly acetylcholine. On the terminal bouton the action potential opens voltage gated calcium channels. There is an influx of calcium in the pre-synaptic cell and it pushes the vesicles that contain acetylcholine. These vesicles will pass through the synaptic cleft and bind to cholinergic receptors on the post synaptic neuron. Each vesicle has a miniature end plate potential of 0.5mV. In a normal action potential, it will depolarize the post synaptic motor neuron from -85mV to approximately 0-15mV. So that's approximately 180 vesicles.* The influx of neurotransmitters (primarily acetylcholine) will depolarize the motor end plate and propagate the action potential. *Threshold of an action potential is approximately -55mV so technically the minimum required to continue an action potential is around 60 vesicles.
Radial Nerve, Ulanar Nerve, and Musculocutaneal Nerve. The ulnar nerve is more commonly known as the "funny bone".
White and grey matter are essentially made up of bundles of nerve fibers (called neurons) that convey nerve impulses between the peripheral nervous system and the central nervous system. The major difference between white and gray matter within the spinal cord is that white matter is primarily composed of myelinated nerve fibers, while the nerve fibers of gray matter are not. Myelinated nerve cells tremendously increase the speed at which the action potential (nerve impulse) moves along the neurons axon. The job of the neurons that make up white matter is to either convey an action potential from a sensory receptor to the central nervous system, or, from the central nervous system out to an effector (such as a muscle or tissue). These neurons are called sensory neurons and motor neurons respectively. Gray matter consists of unmyelinated neurons, called interneurons. Their main duty is to provide communication between the peripheral and central nervous systems. Think of interneurons as a bridge linking two regions together. For unmyelinated neurons, the speed at which an action potential can propagate down the cell's axon is far less than that of the myelinated neurons of white matter.
When a nerve impulse is conducted, the neuronal cell membrane undergoes changes in electrical potential. This starts with a rapid influx of sodium ions into the cell through voltage-gated sodium channels, depolarizing the membrane. This depolarization triggers the opening of adjacent sodium channels, resulting in an action potential that travels along the membrane. After the impulse passes, the sodium channels close, and potassium channels open, allowing potassium ions to exit the cell and restore the resting potential.