The cell body of a neuron is mainly located in the gray matter, nerve nuclei of the central nervous system and the ganglia of the peripheral nervous system. The cell body is the nutritional and metabolic center of the neuron.

1.Cell membrane

2.Nucleus

3. Cytoplasm

1. Dendrites

2..Axon

axonal transport

When the nerve impulse is conducted along the axonal membrane to the axon terminal, it can cause the Ca2 channel on the presynaptic membrane to open. Ca2 enters the precellular component from the outside of the cell and phosphorylates synaptophysin with the participation of ATP. Phosphorylated synaptophysin reduces its affinity to synaptic vesicles and dissociates from synaptic vesicles, causing synaptic vesicles to move to the presynaptic membrane and fuse with them, releasing vesicles through exocytosis. contents into the synaptic cleft. After the receptors on the postsynaptic membrane bind to specific neurotransmitters, the ion channels in the membrane open, changing the ion distribution on both sides of the postsynaptic membrane, causing the postsynaptic neurons (or effector cells) to become excitatory or inhibitory. postsynaptic potential.

It is the largest type of glial cell. The cells were star-shaped, with round or oval nuclei, larger, and lighter staining.

The ends of some processes expand to form footplates, forming a glial boundary membrane on the surface of the brain and spinal cord or attached to the capillary wall, forming a blood-brain barrier.

Can maintain the survival and functional activity of neurons. In brain and spinal cord injuries, astrocytes can proliferate and form glial scars to fill the defects.

The nucleus is oval, with dense chromatin. In silver-stained specimens, there are fewer oligodendrocyte processes.

Oligodendrocytes are involved in forming the myelin sheath of myelinated nerve fibers in the central nervous system

They are the smallest glial cells, with elongated or oval cell bodies, small, flat or triangular nuclei, and deep staining.

Microglia can transform into macrophages, which engulf dead cell debris and degenerated myelin sheaths

Microglia are glial cells with phagocytic ability that evolved from blood monocytes and therefore belong to the mononuclear phagocyte system.

Lining the cavity surface of the cerebral ventricles and the central canal of the spinal cord is a single layer of cuboidal or columnar epithelium with many microvilli on the free surface of the cells. Only some cells in the ventricles have cilia.

Ependymal cells from which choroids produce cerebrospinal fluid

Also known as epineurial cells, they form the myelin sheath of myelinated nerve fibers in the peripheral nervous system.

There is a basement membrane outside the Schwann cell membrane, which can secrete neurotrophic factors, promote the survival of damaged neurons and their axon regeneration, and play a supporting and inducing role.

Neurons are wrapped around the ganglion and are covered with a layer of flat or cuboidal cells. The nucleus is round or oval and deeply stained. There is a basement membrane on the outer surface of the cell, which protects and supports the ganglion.

Myelinated nerve fibers of the peripheral nervous system

myelinated nerve fibers of central nervous system

Wu Lang Feijie

The connective tissue surrounding the surface of a nerve is called the epineurium

A nerve usually contains several nerve fiber bundles. The epithelium of the nerve bundles on its surface and the connective tissue between the bundles together form the perineurium.

Within the nerve fiber bundle, the thin layer of connective tissue on the surface of each nerve fiber is called the endoneurium.

Can feel heat, cold, pain, light touch and other stimuli

Nerve endings are wrapped with a connective tissue capsule, and a common feature of nerve fibers is the loss of myelin before entering the capsule.

(1) Tactile body

(2) Ring layer body

(3) Muscle spindle

Distributed in skeletal muscles, containing motor end plates

Motor nerve endings distributed in the smooth muscles and glands of the myocardium, internal organs, blood vessels, etc.