Anatomy Exam 2 Flashcards
(11 cards)
Spinal nerves
31pairs attach through ventral and dorsal roots
Cervical (8), thoracic(12), lumbar (5), sacral (5), and coccygeal (1)
In the cervical and lumbar regions the spinal cord shows obvious enlargements
Spinal cord functions in three ways
- Involved in sensory and motor innervation of the entire body inferior to the head
- provides a two way conduction pathway for signals between the body and brain
- major center for reflexes
Cauda equina
Collection of nerve roots at the inferior end of the vertebral canal
White matter of the spinal cord
Composed of myelinated and unmyelinated axons that allow communication between different parts of the spinal cord and the cord and brain
Broken into dorsal funiculus, ventral funiculus, and lateral funiculus
Fibers if white matter classified as being one if three types,based on the direction in which they carry nerve impulses
Ascending: sensory info from sensory neurons of the body to the brain
Descending: motor instructions from the brain to the spinal cord
Commissural: white matter fibers tht carry info from one side of the spinal cord to the other
Gray matter of the spinal cord
Consists of a mixture of neuron cell bodies, short, non myelinated neurons, and neuroglia
Gray commisure: composed of unmyelinated axons tht cross from one side of the CNS to the other
Dorsal, ventral, and lateral horn
Ascending pathways
Pathways tht carry information to more rostral regions of the CNS
Descending pathways
Carry info to more caudal regions of the CNS
Important statements about the ascending and descending pathways
Most cross from one side of the CNS to the other (decussate)
Most consist of a chain of 2 or 3 serially linked neurons
All are bilaterally symmetrical
Most are spatially arranged in a Specific way according to the body region they supply
Major ascending pathways
Spinocerebellar
Dorsal column-medial lemniscus
Spinothalamic
Major descending pathways
Direct (pyramidal)
Indirect (extrapyramidal tracts)
