LIFESCI 3K03 Lecture Notes - Lecture 5: Basal Ganglia, Superior Colliculus, Optic Nerve
27 Feb 2018
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Summary: when the muscle spindle afferents fire, the motor neurons is excited and the muscle contracts, when the gtos fire, the motor neuron is inhibited (via an inhibitory interneuron) and the muscle relaxes. These spinal reflexes are automatic but adaptable to sensory stimuli. Their purpose is to avoid injury, and they are considered the basic units of movement and an elementary form of motor coordination example withdrawal reflex: if a finger touches something hot, the finger jerks away from the danger. The burning sensation then becomes an impulse in the sensory neurons, and these neurons synapse in the spinal cord with motor neurons that cause the burned finger to pull away. This spinal reflex is a flexor, or a withdrawal reflex: withdrawal reflexes mediated by pain = this reflex produces two responses. The first is the contraction of flexors on the same side, which results in a withdrawal from the painful stimulus.
