Class Summary - Today we lectured on the peripheral nervous system. The PNS includes 12 pairs of crainial nerves and 31 pairs of spinal nerves and ganglion (which are swellings on the nerves because of collections of cell bodies). We discussed what a reflex arc was. There are 5 steps, receptors detect stimuli, sensory neuron takes message to CNS, integration center processes and interprets message, motor neuron takes message to organ, effector organ responds. We also practiced how this works with a pupil dialating. There are two parts to the PNS the afferent (sensory) and efferent (motor) systems. We focused on the afferent system today. There are two parts to the afferent system; the somatic system that focuses on senses and the visceral system that deals with internal organs.
Objectives - Students will describe the structure of a nerve and distinguish between sensory, motor and mixed nerves. Students will know that there are 12 pairs of cranial and 31 pairs of spinal nerves. Students will describe the structure and function of a reflex arc.