Nerves

A (proto)typical neuron contains three parts: a cell body, an axon, and a tree of dendrites. The cell body is also called the soma, which comes from the Latin for "body". Among many important tasks, the cell body houses the nucleus and most of the other cytoplasmic organelles. For this reason, yet another name for the cell body is the perikaryon, which comes from the Greek for "around the nut", where "nut" refers to the nucleus; thus the cell body is the thing that surrounds the nucleus.
The nucleus is present in the cyton, or main body of the neuron.
Soma or the cell body

The sodium ion concentration is higher on the outside of the cell and potassium ion concentration is higher on the inside of the cell

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autonomic

Nerve root effacement refers to nerve root compression. This is an issue where the root of the nerve is compressed into the spine before exiting it, which can cause some painful back symptoms.

The chemical used to send messages across synapses is acetylcholine or ACh.

* dura

* the arachnoid * the pia mater

No sponges lack organized multicellular organs, such as nerves and muscles.

The vagal nerve stimulator has two parts: an electrode that wraps around the left vagus nerve in the neck; and a pulse generator, which is implanted under the skin below the collarbone. The two parts are connected by a wire.

neurotransmitter carries the nerve impulses from neuron to neuron across a synapse

cranial nerves arise from the brain inside the cranial cavity.

neuromuscular junction

no, they transport vigear to the brain through blood.

It varies:

In the somatic system (skeletal muscle) and parasympathetic branch of the autonomous nervous system (smooth & cardiac muscle) it is usually acetylcholine.

In the sympathetic branch of the autonomous nervous system (smooth & cardiac muscle) it is usually norepinephrine (also called noradrenaline).

There are exceptions, but this is the general rule.

Via chemical messangers that cross the synapse.

Not minerals, it is ions. Calcium ions and sodium ions.

there's the axon (the nerve) the electrical impulse goes down that and covering the axon is the myelin sheath, otherwise known as a fatty sheath which insulates and helps make the electrical impulse go faster. In between each myelin sheath there are synapses (gaps between each one) and the impulse has to cross the gap so neurotransmitters are released which bind to receptors on the other side creating another electrical impulse which makes it travel even faster.

spinal nerve

Sensory nerves are part of the peripheral nervous system which includes the cranial and spinal nerves. They bring impulses to the central nervous system which includes the brain and spinal cord. Peripheral means the sides and that is why the sensory nerves are referred to as the peripheral nervous system.

All of the nervous system is related to the skin because both the nervous system tissues and skin tissues originated in endoderm during the gastrula stage of embryonic development.

The sensory nerves form the link between receptors and the central nervous system (CNS). They carry nerve impulses from stimulated receptors to the CNS. They are also referred to as afferent nerves.

hemisection anywhere in spinal cord, and the result is a mixed sensory deficit.

you'll lose proprioception (two point discrimination) on the same side as the hemisection.

you'll lose pain and temperature sense on the side opposite of the hemisection.

depending on level in spinal cord, the effects will be different

That nerve comes out from behind the eye-ball.

A synapse is the connection between neurons, allowing them to pass signals between each other. A synapse may also be between a neuron and a non-neuron cell, such as a muscle cell, to trigger a reaction.Helping to send messages to and from the brain.

could be preganglionic

Sodium is the first ion to enter the axon, initiating the action potential.

Yes, a neuron is a single cell that serves as the basic functional unit of the nervous system, responsible for transmitting information. In contrast, a nerve is a bundle of multiple neurons, along with their connective tissue, that carries electrical signals between the brain, spinal cord, and other parts of the body. Thus, neurons are the individual components, while nerves are the collective structures that facilitate communication within the nervous system.