dorsal

Examples of dorsal in the following topics:

• Spinal Cord Grey Matter and Spinal Roots

  • The cord has grooves in the dorsal and ventral sides.
  • Axons of these sensory neurons travel into the spinal cord via the dorsal roots.
  • The dorsal root ganglia lie along the vertebral column by the spine.
  • The dorsal root ganglia develops in the embryo from neural crest cells, not the neural tube.
  • The axons of dorsal root ganglion neurons are known as afferents.

• Vertebrate Axis Formation

  • This suggested that the dorsal cells were genetically programmed to form the notochord and define the dorsal-ventral axis.
  • High Wnt signaling establishes the dorsal region while high Shh signaling indicates in the ventral region.
  • Wnt is also involved in the dorsal-ventral formation of the central nervous system through its involvement in axon guidance.
  • Wnt is also involved in the formation of the limb dorsal-ventral axis.
  • Specifically, Wnt7a helps produce the dorsal patterning of the developing limb.

• Somatic Sensory Pathways to the Cerebellum

  • The ventral and dorsal spinocerebellar tracts convey proprioceptive information from the body to the cerebellum.
  • It is part of the somatosensory system and runs in parallel with the dorsal spinocerebellar tract.
  • The dorsal spinocerebellar tract does not decussate, or cross sides, at all through its path.
  • The axon runs via the fila radicularia (nerve rootlets) to the dorsal horn of the gray matter.
  • These central processes travel through the dorsal horn where they synapse with second order neurons of Clarke's nucleus.

• Branches of Spinal Nerves

  • The spinal nerves branch into the dorsal ramus, ventral ramus, the meningeal branches, and the rami communicantes.
  • The dorsal ramus: Contains nerves that serve the dorsal portions of the trunk carrying visceral motor, somatic motor, and sensory information to and from the skin and muscles of the back.
  • The posterior division (dorsal ramus) is labeled at the top right.

• Embryonic Development

  • At the dorsal end of the neural tube, BMPs are responsible for neuronal patterning.
  • A secondary signaling center is then established in the roof plate, the dorsal most structure of the neural tube.
  • BMP from the dorsal end of the neural tube seems to act in the same concentration-dependent manner as Shh in the ventral end.
  • Researchers observed changes in dorsal-ventral patterning; for example zebrafish deficient in certain BMPs showed a loss of dorsal sensory neurons and an expansion of interneurons.
  • Chick embryo of thirty-three hours' incubation, viewed from the dorsal aspect (30x magnification).

• Characteristics of Chordata

  • Animals in the phylum Chordata share four key features: a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail.
  • The dorsal hollow nerve cord derives from ectoderm that rolls into a hollow tube during development.
  • In chordates, it is located dorsally (at the top of the animal) to the notochord.
  • In chordates, four common features appear at some point during development: a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail.

• Establishing Body Axes during Development

  • Animal bodies have three axes for symmetry (lateral-medial, dorsal-ventral and anterior-posterior) which are established in development.
  • However, animal bodies have lateral-medial (left-right), dorsal-ventral (back-belly), and anterior-posterior (head-feet) axes .
  • This suggested that the dorsal cells were genetically programmed to form the notochord and define the axis.
  • The dorsal part of the neural tube contains the alar plate, which is primarily associated with sensation.
  • The dorsal (back) surface of the embryo is toward the top of this page, while the ventral (front) surface is toward the bottom.

• Body Cavities

  • The dorsal cavity is a continuous cavity located on the dorsal side of the body.
  • The meninges is a multi-layered membrane within the dorsal cavity that envelops and protects the brain and spinal cord.
  • The cranial cavity is the anterior portion of the dorsal cavity consisting of the space inside the skull.
  • The vertebral cavity is the posterior portion of the dorsal cavity and contains the structures within the vertebral column.

• Scapula

  • Due to its flat nature, the scapula presents two surfaces and three borders; the front-facing costal surface and the rear-facing dorsal surface, as well as the superior, lateral, and medial borders.
  • The dorsal surface gives origin to the supraspinatus and infraspinatus muscles, and inferiorly to the teres minor and major.

• Autonomic Ganglia

  • The dorsal root ganglia lie along the vertebral column by the spine and develop in the embryo from neural crest cells, not neural tube.
  • A dorsal root ganglion (or spinal ganglion) is a nodule on a dorsal root of the spine that contains cell bodies of nerve cells (neurons) that carry signals from sensory organs towards the appropriate integration center.
  • The axons of dorsal root ganglion neurons are known as afferents.
  • Unlike the majority of neurons found in the central nervous system, an action potential in dorsal root ganglion neuron may initiate in the distal process in the periphery, bypass the cell body, and continue to propagate along the proximal process until reaching the synaptic terminal in the dorsal horn of the spinal cord.
  • The nerve endings of dorsal root ganglion neurons have a variety of sensory receptors that are activated by mechanical, thermal, chemical, and noxious stimuli.