Optic Nerve Symptoms
Optic Nerve
The optic nerve is located in the back of the eye and is also called second cranial nerve and cranial nerve II. the optic nerve is to transfer visual information from the retina to teh vision centres of the brain via electrical impulses. It is made up of ganglionic cells or nerve cells and consists of more than 1 million nerve fibres . Our blind spot is caused by the absence of specialised photosensitive/light-sensitive cells or photoreceptors; the part of the retina where the optic nerve exits the eye. Although the optic nerve is part of the eye, it is considered part of the CNS (central nervous system).
CNS
Optic Chiasma
The optic chiasma is located in the forebrain, directly in front of the hypothalamus. The left and right …show more content…
An action potential is known as an ‘all or nothing’ event.It occurs when a neuron send a message down an axon, away from the cell body.It is an explosion of electrical activity that is created by a depolarising current. When this ‘depolarising current’ reaches -55mV (threshold), a neuron will begin an action potential. If the stimuli is strong enough the charge will be transmitted along the axon to the axon terminals and will them become a message. Not all stimuli will create and action potential and the action potential is always conducted at the same strength and the same speed. A stimulus first causes the sodium channels to open. Due to the sodium ions being on the outside and the neuron having a negative charge on the inside, the sodium ions flow into the neuron. The sodium has a positive charge so the neuron become a positive charge, causing depolarisation. When the potassium channels open it take longer. when they do eventually open, potassium streams out, reversing depolarisation. Roughly at this time the sodium channels start closing. This causes it to go toward -70mV, a repolarisation. The action potential goes past -70mV, a hyperpolarization, due to the potassium channels remaining open too long. Gradually the ion concentrations will go back to the resting level and the cell will return to
The optic nerve is located in the back of the eye and is also called second cranial nerve and cranial nerve II. the optic nerve is to transfer visual information from the retina to teh vision centres of the brain via electrical impulses. It is made up of ganglionic cells or nerve cells and consists of more than 1 million nerve fibres . Our blind spot is caused by the absence of specialised photosensitive/light-sensitive cells or photoreceptors; the part of the retina where the optic nerve exits the eye. Although the optic nerve is part of the eye, it is considered part of the CNS (central nervous system).
CNS
Optic Chiasma
The optic chiasma is located in the forebrain, directly in front of the hypothalamus. The left and right …show more content…
An action potential is known as an ‘all or nothing’ event.It occurs when a neuron send a message down an axon, away from the cell body.It is an explosion of electrical activity that is created by a depolarising current. When this ‘depolarising current’ reaches -55mV (threshold), a neuron will begin an action potential. If the stimuli is strong enough the charge will be transmitted along the axon to the axon terminals and will them become a message. Not all stimuli will create and action potential and the action potential is always conducted at the same strength and the same speed. A stimulus first causes the sodium channels to open. Due to the sodium ions being on the outside and the neuron having a negative charge on the inside, the sodium ions flow into the neuron. The sodium has a positive charge so the neuron become a positive charge, causing depolarisation. When the potassium channels open it take longer. when they do eventually open, potassium streams out, reversing depolarisation. Roughly at this time the sodium channels start closing. This causes it to go toward -70mV, a repolarisation. The action potential goes past -70mV, a hyperpolarization, due to the potassium channels remaining open too long. Gradually the ion concentrations will go back to the resting level and the cell will return to