ANAT2010 Lecture Notes - Lecture 7: Supplementary Motor Area, Betz Cell, Basal Ganglia
Document Summary
Lecture 7 motor pathway i (general organisation: organisation of the motor system (lower / upper motor neurons, spinal control of movement (reflexes, motor programs, brainstem control of movement (posture and balance, cortical control of movement (voluntary movements) Somatic motor system (skeletal: somatic muscles are either flexors or extensors. Somatic musculature: axial muscles: trunk movement, proximal muscles: shoulder, elbow, pelvis, knee movement, distal muscles: hands, feet, digits (fingers and toes) Lower motor neuron: in the ventral horn of spinal cord: upper motor neuron: supplies input to the spinal cord. Alpha (lower) motor neurons: generate force of contraction, small motor units for fine dexterity. Large motor units for anti-gravity muscles of the leg. Proprioception from muscle spindle: group 1a sensory fibre transmits feedback (i. e. length of muscle) to dorsal horn, gamma (lower) motor neuron maintains tone in intrafusal fibre, even when muscle is relaxed. Axons from brain descend via 2 major pathways:
