头骨和近脊神经的细胞学特征 瘤 瘤

The cranial nerves are an important part of the complex network of nerves in the human body. These nerves emerge directly from the brain and are responsible for transmitting essential information between the brain and various parts of the head and neck. There are 12 pairs of cranial nerves, systematically numbered using Roman numerals from I to XII, beginning from the anterior and moving to the posterior of the brain. Each cranial nerve is uniquely identified by names that reflect its function...

Spinal nerves are pivotal conduits in the nervous system, bridging the central nervous system (CNS) with the peripheral nervous system (PNS). These nerves enable a complex communication network between the brain, spinal cord, and the rest of the body, facilitating sensory input, motor output, and autonomic functions.
There are 31 bilateral pairs of spinal nerves, each emerging from the spinal cord through the intervertebral foramina—openings between adjacent vertebrae. These nerves are...

The cranial part of the parasympathetic division plays a crucial role in regulating the visceral functions of the head and specific structures in the neck, thoracic, and abdominopelvic cavities. Preganglionic fibers of the parasympathetic division exit the brain through cranial nerves III (oculomotor), VII (facial), IX (glossopharyngeal), and X (vagus), delivering parasympathetic output to the respective visceral structures.
The vagus nerve (cranial nerve X) alone accounts for approximately 75...

The spinal cord is the body’s major nerve tract of the central nervous system, communicating afferent sensory information from the periphery to the brain and efferent motor information from the brain to the body. The human spinal cord extends from the hole at the base of the skull, or foramen magnum, to the level of the first or second lumbar vertebra.

The Peripheral Nervous System (PNS) is a crucial component of the body's neural network, extending beyond the central nervous system (CNS) to bridge the gap between the CNS and the external environment. It encompasses nerves, ganglia, and sensory receptors.
Nerves
The nerve is a bundle of axons that serves as the communication highway in the PNS. Each nerve is ensheathed in a protective layer of connective tissue called the epineurium. This outermost layer safeguards the nerve and supports the...

The cross-sectional anatomy of the spinal cord offers a detailed view of its complex structure and function within the central nervous system. At the core of the spinal cord lies the gray matter, characterized by its butterfly or "H"-shaped appearance in cross-section. This central region is enveloped by white matter, with the overall structure divided into symmetrical halves by the dorsal median sulcus and the ventral median fissure.
Gray Matter and its Components
Central to the gray matter is...