What is the longest nerve in the human body

The sciatic nerve is the thickest and longest nerve in the whole body, the initial segment can be up to 2cm wide, and it exits the pelvic cavity through the inferior piriformis foramen, is located in the deep surface of the gluteus maximus, descends to the posterior femoral region between the sciatic tuberosity and the greater trochanter, and then descends to the deep surface of the long head of the biceps femoris muscle, and is generally divided into two terminal branches of the tibial nerve and the common peroneal nerve above the popliteal fossa. The sciatic nerve trunk emits muscular branches in the posterior femoral region and is distributed in the biceps femoris, semitendinosus and semimembranosus muscles, and at the same time emits branches distributed in the body surface projection of the sciatic nerve in the hip joint: from the midpoint of the line between the sciatic tuberosity and the greater trochanter, down to the midpoint between the medial and lateral condyles of the femur, 2 3 segments of this line are projections, and tenderness often occurs on this line in sciatica.

Hehe, this is the content of page 405 on "Systematic Anatomy (6th Edition)" (People's Medical Publishing House) This semester has just been completed.

Although a neuron is only a cell, the total length of the cell is often considerable due to the elongated axons. Human neurons can grow up to 1 meter long. Neuronal fibers in the giraffe spinal cord can extend all the way to the tips of the toes of the hind limbs, and the full length of this neuron is even more than 1 meter, while the corresponding neurons of whales are longer, up to 10 meters.

Axons are generally small in diameter. Some tiny axons in the human brain are as small as 1 micron in diameter, but some animals, such as squid, have giant axons as large as 1 millimeter in diameter.

I learned it in the first year of junior high school biology class. It can also be used. Can you give points.

There are long and short.

It can be about the same height as a person.

The short ones may be only a few microns.

The nervous system can be divided into the central nervous system and the peripheral nervous system, and the central nervous system includes the brain and spinal cord, which are located in the cranial cavity and cone canal, respectively. The peripheral nervous system includes cranial and spinal nerves. Cranial nerves are connected to the brain, a total of 12 pairs; The spinal nerves are connected to the spinal cord and there are 31 pairs in total.

I can't say how many nerves, but the nervous system, people have eight major nervous systems, many small ones.

Cranial nerves, also known as "cranial nerves", have 12 pairs of cranial nerves in the human body, that is, there are 24 of them, namely:

Olfactory nerve optic nerve.

Oculomotor. Trochlear nerve.

Trigeminal nerve. Abducens facial nerve.

Vestibocochlear nerve.

Nine glossopharyngeal nerves.

Vagus. Accessory nerve, hypoglossal nerve.

The central nervous system is a part of the nervous system, and these groups of neurons that regulate a specific physiological function are called the nerve center, the respiratory center, so the answer is to divide the brain and the spinal cord into two parts in the gray matter, and the motor center and so on.

For example, the central nervous system is divided into which parts, and the neuronal cells with the same function come together to form the auditory center.

The landlord did not understand the difference between the two concepts of the nerve center and the central nervous system, and regulated a certain corresponding physiological activity of the human body.

The nerve center has a visual center. The nervous system is made up of the central nervous system and the peripheral nervous system.

Sciatic nerve. The sciatic nerve is the largest, thickest, and longest nerve in the human body and is the main nerve responsible for muscle movement and sensation in the back of the thigh, throughout the calf, and in the foot. It mainly emits two main branches:

Common peroneal and tibial nerves. Because of the wide range of sciatic innervation, damage can have a serious impact on the function of the entire lower extremity.

The sciatic nerve is the thickest and longest nerve in the whole body, the initial segment can be up to 2cm wide, and it exits the pelvic cavity through the inferior piriformis foramen, is located in the deep surface of the gluteus maximus, descends to the posterior femoral region between the sciatic tuberosity and the greater trochanter, and then descends to the deep surface of the long head of the biceps femoris muscle, and is generally divided into two terminal branches of the tibial nerve and the common peroneal nerve above the popliteal fossa. The sciatic nerve trunk originates in the posterior femoral region and branches in the biceps femoris, semitendinosus, and semimembranosus muscles, while the branches originate in the hip joint.

Projection of the sciatic nerve body surface: from the midpoint of the line between the sciatic tuberosity and the greater trochanter, down to the midpoint between the medial and lateral femoral condyles, 2 3 segments of this line are projections, and tenderness often occurs on this line in sciatica.

Hehe, this is the content of page 405 on "Systematic Anatomy (6th Edition)" (People's Medical Publishing House) This semester has just been completed.

General knowledge questions in the public examination: What is the largest cell in the human body, nerve cells?

Located in the cranial cavity and spinal canal, the nervous system is the most concentrated and complex part of the nervous tissue, and the nervous system is the whole device composed of nervous tissue in the human body.

It is mainly composed of neurons.

The nervous system is made up of two parts: the central nervous system and the peripheral nervous system, which is located throughout the body.

The central nervous system, which includes the brain and spinal cord, is located in the cranial cavity and spinal canal, respectively, and is the most concentrated and complex part of the nervous tissue. There are centers that control various physiological functions. The peripheral nervous system includes various nerves and ganglia.

Among them, the ones connected to the brain are called cranial nerves, the spinal nerves that are connected to the spinal cord, and the autonomic nerves that innervate the internal organs are called autonomic nerves. Various types of nerves are connected to other organ systems through their terminals.