Guided reading questions ANS and Reflexes Please note the page numbers might be slightly different between the eText and the printed version Use the titles subtitles mentioned below to locate the specific text Read pages 374 380 Section 14 1 Figure 14 11 and the relevant text 367 370 Section 13 6 up to and not including Sensory and motor neuron disorders Do not hesitate to use the web when a question is not specifically addressed in the textbook Section 14 1 and Figure 14 11 Review the text and figures and answer the following questions 1 The autonomic nervous system ANS is sometimes called the visceral nervous system as it controls mostly visceral effectors Can you think of non visceral effectors that are controlled by the ANS Knee jerk reaction or hand retracing from touching fire 2 The ANS is sometimes called the fine tuning system How does this definition concur with the following statement Visceral effectors do not depend on the autonomic system to function In other words how is the somatic and autonomic system differ with regards to their effect on the target organs Visceral effectors do not depend on the autonomic system because the initial efferent neuron synapses onto the postganglionic neuron within a ganglion in the PNS while the somatic system directly innervates its target cells 3 What are the five components of the visceral reflex arc and for that matter of any reflex arc Afferent sensory neurons brain spinal cord CNS efferent motor neurons autonomic ganglia 4 With regards to the five components addressed in question 3 identify those components in the reflex arc which is depicted in Figure 14 1 Signals go through the afferent sensory neurons sent to the brain or spinal cord The central nervous system integrates the stimuli The brain spinal cord then sends out motor impulses that lead to the autonomic ganglia The Autonomic ganglia then relays that information to target organs prompting a motor response 5 Describe in two sentences each of the two division of the ANS The parasympathetic division of the ANS deals with maintaining the body s homeostasis when at rest with functions such as activating digestion The sympathetic division deals with homeostasis when the body is in action and physical activity and makes sure the body is equipped to deal with such situations and does things like slow digestion 6 Define the following terms Sympathetic tone The condition of a muscle when the tone is maintained predominantly by impulses from the sympathetic nervous system Parasympathetic tone is dominant in the heart and maintains heartbeat The parasympathetic division is typically an inhibitory system while the sympathetic division is an excitatory one 7 True or false 8 Figure 14 2 and text Summarize the differences between the somatic and the autonomic nervous systems with regards to these factors Neurotransmitters Number of fibers myelination effectors effect excitatory vs inhibitory Neurotransmitters only stimulate in somatic stimulate or inhibit in autonomic Number of fibers 1 vs 2 Effectors skeletal vs cardiac muscle cells and glands Effect excitatory vs both 9 Figure 14 11 Summarize the differences between the sympathetic and the parasympathetic nervous systems with regards to these factors Neurotransmitters Length of fibers receptors Neurotransmitters AcH pre and NE epinepherine AcH post vs AcH Length of fibers long vs short Receptors nicotinic post for both adrenergic muscarinic sympathetic target vs muscarinic parasympathetic target Section 13 6 The nature of reflexes Skip the Flexion and crossed extension spinal reflexes on p 370 10 True or false Explain You are not aware conscious of a stimulus that triggered a reflex You can become conscious by sight independent of the reflex 11 Define the five components of a reflex arc 1 receptors sensory detect stimulus 2 afferent neurons lead to CNS 3 interneurons in CNS 4 efferent neurons carry motor signal away from CNS 5 motor effector that carries out motor response 12 What type of reflex is the simple stretch reflex monosynaptic 13 What serves as the receptor in the reflex arc of the stretch reflex Muscle spindles 13b How does it deliver the message of stretch Stretching stretches the intrafusal fibers in muscle spindles which opens mechanically gated ion channels in primary and secondary afferents Primary and secondary afferents transmit action potential to spinal cord 14 True or false Explain All reflexes have an integration center a CNS component even monosynaptic reflexes Must all go to the CNS to integrate the stimulus 15 What are synergists and antagonists Synergists fix muscles in place to help cancel out extra motion from antagonist Antagonist inhibit movement 16 In the reflex which is depicted in figure 13 19 which muscle serves as the antagonist of the biceps Tricep that innervates the hamstrings Action potential 17 When responding to a stimulus what type of potential is generated in the alpha motor neuron 18 What type of potential is generated in the alpha motor neuron that innervates the quadriceps Action potential 19 Is the reflex depicted in figure 13 19 a monosynaptic or a polysynaptic reflex monosynaptic