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Nerve fibres (or axons) all join together in bundles to make larger 'nerves', i assume you mean ''why are all NERVES not all large'', and not nerve fibers, and by large i think you mean thick??? (sorry if i am wrong..)
The largest nerves are just groups of nerve fibers that have joined together into one canal as they are all running down the same path e.g. down the arms and legs). As the nerve travels down its path, individual nerve fibers will leave the nerve canal and travel off on their own at some point to innervate different parts of the area (muscles, tissues etc..), and so the nerve decreases in thickness.
Therefore the largest nerves (e.g the sciatic nerve) are only large because all the individual nerves coming off the spinal cord are joining together in one canal to travel down to the leg to innervate its different parts. As the nerve travels further down (ie. to the foot) the nerve gets much smaller as many of its fibres have already branched off to innervate the upper leg muscles etc.
Therefore some nerves are only wide because they holds alot of nerve fibers within it.
..If you do mean, why are they not 'large' in relation to length, it is because some places needing innervating are closer to the spinal cord than others, and so they dont need to be as long!!
(e.g. the kidney is closer to the spinal cord than the botton of the foot!!)
What else can I help you with?
Why a peripheral nerve such as the sciatic nerve can contain nerve fiber from several spinal nerves?
The reason why a peripheral nerve such as the sciatic nerve can contain nerve fiber from several spinal nerves is owing to nerve plexuses. These are networks of nerves all tangled together and found mostly in the limbs.
Would conduction speed of a nerve fiber be the fastest in a large or small myelinated fiber?
The conduction speed of a nerve fiber is fastest in large myelinated fibers. This is because myelin acts as an insulator, allowing for faster propagation of the action potential by saltatory conduction in large fibers compared to small unmyelinated fibers.
What are components of a nerve fiber?
A nerve fiber consists of the axon, which transmits nerve impulses, along with protective covering called myelin sheath, Schwann cells that produce myelin, and the endoneurium which surrounds individual nerve fibers.
The speed of nerve impulse transmission through the axon of a sensory neuron will be quickest in?
I'm guessing; "myelinated nerve fibres" contrary to the much slower "non-myelinated nerve fibres"
What do you call the slender nerve fiber?
The slender nerve fiber is called an axon. It is the long, slender projection of a nerve cell that transmits electrical impulses away from the cell body to other neurons, muscles, or glands.
Why a peripheral nerve such as the sciatic nerve can contain nerve fiber from several spinal nerves?
The reason why a peripheral nerve such as the sciatic nerve can contain nerve fiber from several spinal nerves is owing to nerve plexuses. These are networks of nerves all tangled together and found mostly in the limbs.
What is required to maintain nerve fiber sheath?
required to maintain nerve fiber sheath
What is the difference between the contour and magnitude of single nerve fiber and nerve trunk?
What is the difference between the contour and magnitude of single nerve fiber and nerve trunk?
Would conduction speed of a nerve fiber be the fastest in a large or small myelinated fiber?
The conduction speed of a nerve fiber is fastest in large myelinated fibers. This is because myelin acts as an insulator, allowing for faster propagation of the action potential by saltatory conduction in large fibers compared to small unmyelinated fibers.
The longest nerve of the human body?
The sciatic nerve (also known as the ischiatic nerve) is a large nerve fiber in humans and other animals. It begins in the lower back and runs through the buttock and down the lower limb. It is the longest and widest single nerve in the human bod
What is the all none law of muscle response?
all-or-none law is the principle that the strength by which a nerve or muscle fiber responds to a stimulus is not dependent on the strength of the stimulus. If the stimulus is any strength above threshold, the nerve or muscle fiber will give a complete response or otherwise no response at all
Mechanism of nerve conduction?
Nerve conduction involves the transmission of electrical impulses along the length of a nerve fiber. When a nerve is stimulated, sodium ions rush into the nerve cell, causing a change in electrical charge. This creates an action potential that travels down the nerve fiber, activating adjacent areas and allowing the signal to be transmitted. Once the impulse reaches its destination, neurotransmitters are released to stimulate the next nerve cell or muscle fiber.
What is the site where the muscle fiber and nerve fiber meet called?
Well of course they meet at the neuromuscular junction
What cause a nerve impulse move along the nerve fiber?
Electrical diferences.
What causes a nerve impulse move along the nerve fiber?
Electrical diferences.
What are components of a nerve fiber?
A nerve fiber consists of the axon, which transmits nerve impulses, along with protective covering called myelin sheath, Schwann cells that produce myelin, and the endoneurium which surrounds individual nerve fibers.
The speed of nerve impulse transmission through the axon of a sensory neuron will be quickest in?
I'm guessing; "myelinated nerve fibres" contrary to the much slower "non-myelinated nerve fibres"
