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Spinal Cord and Reflexes
Fundamentals of Human Biology II
SCB 204
Overview
Meninges
Spinal Nerve Function
Spinal Cord Cross-Section
The total number of paired spinal nerves isa. 12b. 26c. 31d. 48
Dissected Ventral Surface
Ascending and Descending Tracts
Ascending Tracts
� Fascicular - touch, somesthesis� Spinocerebellar - Proprioception� Spinothalamic - pressure, pain, crude
touch
Descending Tracts
� Corticospinal - somatic motor function� Vestibulospinal - equilibrium� Tectospinal - reflex postural movements
in response to visual and auditory stimuli
� Rubrospinal - reduced function in humans. thought to control some gross action of flexors and extensors (walking)
Why is there no cerebellospinal pathway?
� A. the cerebellum does not have a motor function.
� B. it’s included with the cerebrospinal pathway
� C. it’s included with the tectospinal pathway
� D. both B and C
Which part of the brain is involved with somatic motor function?
� A. precentral gyrus� B. thalamus� C. cerebellum� D. all of these
Sensory Pathways
Somatic Reflex Arc
Ipsilateral andContralateral Reflexes
Types of Reflexes
Motor Integration
Sensory Endings
� Mechanoreceptors - � Thermoreceptors - � Photoreceptors - � Chemoreceptors -� Nociceptors -
Cutaneous Endings
Cutaneous Endings
Dermatomes
If a reflex involves your big toe, what is its pathway?
� A. brachial plexus and cervical cord� B. thoracic plexus and thoracic cord� C. lumbar plexus and lumbar cord� D. sacral plexus and sacral cord
Spinal Nerve Structure