Nerves

When nerve cells or neurons are stimulated they undergo chemical changes which make little waves of electricity or nerve impulses. These are based mainly on the movement of positively charged sodium and potassium ions through the neurons cell membrane.When the impulses reach a junction-synapse-they trigger the release of chemicals called neurotransmitters. These then cross the synapse and stimulate the receiving neuron to fire impules of their own.

Dendrites collect nerve impulses and Axons convey impulses away from cell.

Nerves vary in size. Nerves like the sciatic nerve are large while other are small. There are three types of nerves in the human body. Afferent, efferent, and mixed.

The dendrites are the root-like structures of a nerve that receive electrical impulses The dendrites then conduct the impulse to the cell body. Dendrites are root-like structures of a nerve cell that receive impulses and conduct them to the cell body.

from spinal nerve to posterior (dorsal) root

oculomotor nerve control the muscle that move the eyeball.
close vision
Movement of the eyes.
Focusing the eyes on close objects.

There is a special cell in our body that is part of the nervous system. It receives messages in the muscles sent from the motor neurons in our brain. These cells are called effectors.

Are at the back of the eye, they connect the eyes to the brain. They also cross to the opposite side so the information collected by the right eye is processed by the left hemisphere and vice versa

The axon is the output structure of a nerve cell. Many times it is myelinated like an electrical wire.

The receiving neuron is less likely to generate action potential.

ganglion cells

Afferent

If by 'replaced' you mean, can the body grow new ones like with blood and tissue cells, then no, not at present. There is some promising research being done with stem-cell therapies, but they're a long way from being able to effectively regrow nerve tissue.

Coniction

Nerve cells send electrical impulses called synapse. These electrical stimulations travel from cell to cell, up to the brain and back. Nerves also produce different types of chemicals to manipulate the synapse.

Preganglionic because they are myelinated.

FALSE

The Pontine Respiratory Group stimulates abnormal breathing, called inspiration, during inhalation. The PRG consists of a network of neurons located in the rostral dorsal lateral pons.

retina

The synaptic transmission is where the communication between the terminal button and the dendrite occur. What happens is the impulse moves along the axon and release neurotransmitter from the end plate of the presynaptic neuron and are diffused across the synaptic cleft. This creates a depolarization of the dendrites of the postsynaptic neuron. When that happens the postsynaptic's sodium channels to open and start the action potential. Once the channels are open an enzyme called cholinesterase is released from postsynaptic membrane and it acts to destroy the neurotransmitters. When they are destroyed the sodium channels close and begins recovery.

I believe it's Na+

the nerve of the ear sends messages to the brain to allow you to hear.

The spinal accessory nerve, or cranial nerve XI (eleven), is a purely motor nerve which innervates the trapezius and sternocleidomastoid muscles. The sternocleidomastoid muscles are used to turn the head.

The Accessory nerve also provides somatic motor fibers to muscles of the soft palate, pharynx, and larynx (spinal and medullary fibers respectively.)

The most important one is the brain. A surgeon can do surgery on the brain while the patient is awake.

structurally they are very similar with the only real difference being that the myelinated (M) nerve (neurone) has schwann cells on its axon surface, but functionally they are very different as the M transmitts nerve impulses alot faster than the non-myelinated(NM) as it has nodes ranvier that allow the impulse to jump from gap to gap between schwann cells and so sppeding the rate at which it can depolarise the membrane to allow transmittion of the impulse, i could go on alot more but i wont :) hope this helps

yours scincerly a uni student trying to look smart ;)

i got to OXFORD (brookes) ...