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level: Level 1

Questions and Answers List

level questions: Level 1

Question	Answer
motor neurons of anterior grey horn of spinal cord to innervate skeletal muscle	Lower motor neurons
Neurons of cortex and other supraspinal centres send their axons to LMN for higher cortical control	Upper motor neurons
cerebellum receives information about every movement from	Corticopontocerebellar pathway
pyramidal tracts: end on	anterior horn ( motor) neuron cells of spinal cord
Origin from motor cortex Descend through corona radiata then Decussate at Junction of medulla & spinal cord 75% of fibres cross to opposite side Terminate in anterior horn cells 25% uncrossed fibres Cross later in spinal cord and descend to cervical and upper thoracic segments	Corticospinal or Pyramidal tracts
Corticospinal or Pyramidal tracts lesion cause	Loss of voluntary skilled movements on opposite side
Originate in Red nucleus in MB in superior colliculus level Cross to opposite side in MB Terminate in anterior horn of SC • Facilitate activity of Flexor muscles &Inhibits extensor	Rubrospinal tracts
Originate in neurons in Superior colliculus cross to opposite side in MB Terminate in upper cervical segments of SC Coordinates visual – body movements: turning head to source of visual stimuli +coordinating extraocular muscle movement	Tectospinal Tracts
Originate in Vestibular nuclei in medulla & pons Lateral division Ends on anterior horn of same side Facilitate activity of extensor muscles Medial division give longitudinal fasciculus for control and balance of head and eye movements	Vestibulospinal tracts
Originate in Reticular formation in medulla and pons Influence voluntary and reflex motor activity Mainly proximal limb muscles and axial muscles , can control sympathetic and parasympathetic outflow & cardiorespiratory centres	Reticulospinal tracts
Flaccid paralysis ,Atrophy of muscles ,Muscle fasciculations & Loss of reflexe	Lower Motor Neuron lesions
Loss of fine, voluntary skilled movements in opposite side Babinski’s sign +ve Absent of superficial abdominal cremasteric reflex	Lesion of the pyramidal tracts
Spasticity or hyper tonicity , Rigidity ,Severe paralysis ,Clasp knife reaction	UMN (extra pyramidal) lesion