Nerves

The axon is the elongated fiber that extends from the cell body to the terminal endings and transmits the neural signal. The larger the axon, the faster it transmits information. Some axons are covered with a fatty substance called myelin that acts as an insulator. These myelinated axons transmit information much faster than other neurons.

"http://wiki.answers.com/Q/How_many_spinal_disks_are_there_in_human_body

Neurons communicate with each other by sending electrical signals across a synapse. In a three neuron loop the series of events that happen in synaptic transmission are as follows:

• Neuron 1 sends an electrical signal (action potential) down its axon towards the synapse.
• The action potential causes the release of neurotransmitters (chemicals) from the terminal button of Neuron 1 into the synaptic cleft.
• The neurotransmitters bind to the receptors of Neuron 2.
• This binding triggers a new action potential in Neuron 2 which travels down its axon.
• The action potential causes the release of neurotransmitters (chemicals) from the terminal button of Neuron 2 into the synaptic cleft.
• The neurotransmitters bind to the receptors of Neuron 3.
• This binding triggers a new action potential in Neuron 3 which travels down its axon.
• The action potential causes the release of neurotransmitters (chemicals) from the terminal button of Neuron 3 into the synaptic cleft.
• The neurotransmitters bind to the receptors of Neuron 1 closing the loop.

This series of events is repeated continuously allowing for the communication between neurons in a three neuron loop.

Absolute refractory period (time which local area of the membrane

has surpassed the threshold potential and will not respond to any stimulus).

The brain and spinal cord; the cerebro-spinal axis; myelencephalon.

Everyone is aware that caffeine is useful for overcoming tiredness, but not many people understand how. Caffeine actually affects different tissues in different ways; the most stimulating effect actually occurs in the brain. Normally when you start to get sleepy, adenosine molecules bind to receptor proteins stimulating drowsiness. Because caffeine is similar in structure to the adenosine molecules, it binds to the receptors instead, blocking the site from the adenosine. Caffeine also stimulates epinephrine in the heart and liver cells, increasing heart rate and stimulating glycogen conversion to glucose.

1. The neuron fires an action potential, sending the electrical signal down the axon.

In terms of the nervous system, muscles and glands are given the generic term effector organs. Impulses are picked up from receptors, which then travel to the brain, which sends orders along the motor neurons to these effector organs. In the case of reflex actions, however, the brain is not involved, and the process is done much faster as a result.

Cervical- diaphragm & muscles of shoulder & neck

brachial- deltoid muscle of shoulder, triceps & extensor muscles of forearm, flexor muscles of forearm & some muscles of hand, flexor muscles of arm, wrist & many hand muscles

lumbar- lower abdomen, buttocks, anterior thighs, and skin of anteromedial leg & thigh, adductor muscles of medial thigh & small hip muscles; skin of medial thigh & hip joint

sacral- lower trunk & posterior surface of thigh & leg, lateral aspect of leg & foot, posterior aspect of leg & foot, gluteus muscles of hip

gastrocnemius muscle

up a unicorns tail end

The mass of an adult human brain is approximately 1300 to 1400 grams (2.87 to 3.1 pounds).

A newborn human brain is about 350 to 400 grams (0.77 to 0.88 pounds).

The average Male's brain weighs 1360 grams (3 pounds)

The average Female's brain weighs 1250 grams (2.8 pounds)

The brain weights of some well known people:

The brain of Albert Einstein weighed 1230 grams (2.71 pounds)

The brain of the German mathematician Carl Friedrich Gauss weighed 1492 grams (3.29 pounds)

The brain of the leading poet of Russian Revolution Vladimir Vladimirovich Mayakovsky weighed 1700 grams (3.75 pounds)

Accessory nerve is the eleventh cranial nerve. It originates from the lateral of the olives ( a structure in the medulla of the brain). It supply the motor function only. The muscles supplied by Accessory nerve is trapezius muscle and the sternocledomastoid muscle.

I had my accessory nerve cut by accident in a lymph node removal procedure. I was not able to move my arm for 2 weeks. I started doing physical therapy because at the time I didn't know my nerve was cut, we thought it was just maybe slightly damaged. Therapy helped with easing pain. I can't shrub my shoulder up & down or shrub it forward & back, or squeeze my scapula together. I also can't raise my arm past my chest. I can't make a wingspan what so ever. I also lost the feeing in the side of my face, neck, parts of my chest around the clavicle area, shoulder, & scapula. The pain is terrible, it will stop you in your tracks. I sometimes scream when I receive nerve shocks. I have a lot a pain in my head too. My vision in one eye became blurry at times & the hearing in my ear was very pore, it sounded like I a "wooshing" sound kinda like a seashell to my ear. I can't stand for more than 5 minutes before the pain gets unbearable. Reclined or laying down relieves slot of pain. & I can go on forever about symptoms.

I actually just had surgery last week in attempt to fix my arm but I wont actually know if the surgery worked for 6 months when I have an EMG test done, but until then I'm in an arm immobilizer, they have my arm strapped down to my side 24/7 & I can never take it off, not even in the shower, & I can only sleep on one side for 3 weeks & this thing hurts, I'm like bruised around my ribs from it. I can't even get in a car. The reason why I have to wear that thing is because the stitched that they used to reattach all the severed nerves are smaller than a strand of hair & any jerking motion can tear open the stitches.

If anybody knows of anyone who has this injury, comfort them. It's a very devastating, depressing, & a very painful injury. It's not a injury where you have surgery one day & are back at work 2 weeks later, it's a 2-4 year recovery span. So lots of physical therapy and prayers that we all have the best outcome. It puts your life on hold. And my best advice to people enduring this same injury is to stay positive as hard as you can. Do not let this injury get the best of you. There will bee a light at the end of every tunnel

These are nerves in animals. They include central and peripheral; peripheral include somatic and autonomic.

acetylcholine

Neurons are responsible for transmitting a stimulus across a synapse. The electric potential of the neuron is sensitive to changes in the resting state and sets off electric transmissions.

A nerve cell found entirely within the central nervous system that acts as a link between sensory neurons and motor neurons.

neurofibrils

neurofibrils

Both are Wrong, but I do not the correct answer. I think it's NISSL CELL

The Dendrites provide the receptive surface for communications. (In some types of neurons the cell body provides such surface)

Neither neurofibrils or Nissl cell is wrong. The correct answer is the dendrites. Dendrites are the structures on the neruons that are the main receptive surfaces for nerve impulses.

No, axons carry impulses away from the nerve cell body.

Pinched nerves usually cause symptoms either in their immediate vicinity or downstream (in an arm due to a pinched nerve in the neck area). It is highly unlikely that "weird sensations in the brain" would result from a pinched nerve. However, pain and anxiety associated with a pinched nerve could make a person feel uncomfortable and unlike his or her usual self.

This would depend on the location and size of the tumor. For information on the most important things to look for in Brain Injury rehabilitation hospitals or for other brain injury related questions see

http://www.brainandspinalcord.org/brain-injury-treatment-centers/index.html

You might get slower reactions.

sensory neuron or receptor neuron.

Acetylcholine is a neurotransmitter,a chemical released by a neuron to change the membrane properties of another cell. In this case, the release of ACh from the synaptic terminal can alter the permeability of the sarcolemma and trigger the contraction of the muscle fiber.