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A neuron (also known as a neurone or nerve cell) is an excitable cell in the nervous system that processes and transmits information by electrochemical signaling. Neurons are the core components of the brain, spinal cord, and peripheral nerves.
Sectional organization of spinal cord. The spinal cord is the main pathway for information connecting the brain and peripheral nervous system. [3] [4] Much shorter than its protecting spinal column, the human spinal cord originates in the brainstem, passes through the foramen magnum, and continues through to the conus medullaris near the second lumbar vertebra before terminating in a fibrous ...
A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal nerves, one on each side of the vertebral column. [1] [2] These are grouped into the corresponding cervical, thoracic, lumbar, sacral and coccygeal regions of the spine. [1]
The number of vertebrae in a region can vary but overall the number remains the same. In a human spinal column, there are normally 33 vertebrae. [3] The upper 24 pre-sacral vertebrae are articulating and separated from each other by intervertebral discs, and the lower nine are fused in adults, five in the sacrum and four in the coccyx, or tailbone.
Composition and central connections of the spinal nerves; Pathways from the brain to the spinal cord; The meninges of the brain and medulla spinalis; The cerebrospinal fluid; The cranial nerves. The olfactory nerves; The optic nerve; The oculomotor nerve; The trochlear nerve; The trigeminal nerve; The abducens nerve; The facial nerve; The ...
The fifth lumbar spinal nerve 5 (L5) [5] originates from the spinal column from below the lumbar vertebra 5 (L5). L5 supplies many muscles, either directly or through nerves originating from L5. They are not innervated with L5 as single origin, but partly by L5 and partly by other spinal nerves. The muscles are: gluteus maximus muscle mainly S1
Their neuroanatomy is therefore better understood. In vertebrates, the nervous system is segregated into the internal structure of the brain and spinal cord (together called the central nervous system, or CNS) and the series of nerves that connect the CNS to the rest of the body (known as the peripheral nervous system, or PNS). Breaking down ...
The axons of the tract cells cross over (decussate) to the other side of the spinal cord via the anterior white commissure, and to the anterolateral corner of the spinal cord (hence the spinothalamic tract being part of the anterolateral system). Decussation usually occurs 1-2 spinal nerve segments above the point of entry.