Anatomy and Cell Biology 3319 Lecture 6: lab 6 sensory & motor pathways
3 sensory pathways: carry afferent info from sensory receptors to the brain. Sensory receptor in periphery -> first order sensory neuron -> synapses with second order neuron in spinal cord. Second order neuron may synapse with a third order neuron. Starting point: second order neurons in the dorsal horn. Type of information it carries: subconscious propiroception from lower limbs and trunk. Starting point: central process of first order neurons enter the dorsal root. Inferior parts of the body -> ascends through medial fasciculus gracilis (dorsal column) -> synapses with seocnd order neurons at the nucleus gracilis in the medulla. Superior parts of the body -> ascends thorugh lateral fasciculus cuneatus (dorsal column) -> synapses with second order neurons at nucleus cuneates in the medulla. Axons from nucleus cuneatus and nucleus gracilis -> form medial lemniscus tract -> decussate in the medulla. Medial lemniscus tract -> ascend through pons and midbrain to the thalamus.