Histology Photomicrographs

Human Anatomy and Physiology (BIOL& 241L-242L)
Karen Hart, Peninsula College

• Epithelial tissue
• Connective tissue proper
• Skin
• Cartilage and bone
• Skeletal muscle, smooth muscle
• Nervous system
  • Neurons and glia
  • Nerve cross section
  • Nerve longitudinal section
  • Spinal cord
  • Dorsal root ganglion
• Cardiovascular system
• Lymphatic system
• Respiratory system
• Digestive system
• Urinary system
• Reproductive system
•  
• Histology home page

Nervous system: Dorsal root ganglion

The cell bodies of sensory neurons are located outside the brain and spinal cord in ganglia or in organs of the special senses.

Ganglia located along the spinal nerves and certain cranial neves house the cell bodies of sensory neurons whose dendrites are located in the skin, muscles, tendons, joints and internal organs. These dendrites monitor touch (various kinds), stretch, temperature, and pain.

The ganglia associated with the spinal nerves are called dorsal root ganglia. The cell body of each sensory neuron in the dorsal root ganglion has a long axon which extends from the dendrites (located for example in the skin), to the cell body in the dorsal root ganglion and then continues to the spinal cord. The section of the axon that runs from the ganglion to the spinal cord is bundled with similar axons. These bundles are called dorsal roots.

The 40X image shows a dorsal root ganglion and spinal cord.

drg = dorsal root ganglion

dh = dorsal horn of spinal cord gray matter

vh = ventral horn of spinal cord gray matter

In the dorsal root ganglion at 100X and 400X the sensory neuron cell bodies ncb are visible as large cells stained light and medium purple. Glial cells called satellite cells sc surround the neurons. The satellite cells in this image are the small dark purple cells.

The red stained areas of the ganglion are areas of axons enclosed by Schwann cells. The Schwann cell cytoplasm stains red; the Schwann cell nuclei are purple. Where the axons are cut in cross section one can see some myelinated axons ma. The area labeled dr is a part of the dorsal root that runs from this ganglion to the spinal cord.