In: Anatomy and Physiology
The
sites of origin for the sympathetic division are?
a. brain
and sacral
b. brain
and thoracic
c. thoracic
and lumbar
d. lumbar
and sacral
The sites of origin for sympathetic division are?
Answer: c) thoracic and lumbar.
Explanation: Sympathetic and parasympathetic nervous system are divisions of autonomic nervous system. Autonomic nervous system is a part of peripheral nervous system which has nerves arising from brain and spinal cord that controls the activities of smooth muscles, glands and viscera.
Sympathetic nervous system arises from the thoracic and lumbar segments of spinal cord hence called as thoraco-lumbar outflow. It regulates the fight and flight response of the body. The pre-ganglionic fibers of sympathetic nervous system are short and post-ganglionic fibers are long and its ganglia are located as sympathetic chains on either side of spinal cord. It causes excitatory physiological state in the body. Its post-ganglionic fibers release norepinephrine and pre-ganglionic fibers release acetylcholine as the neurotransmitter.
The sites of origin of parasympathetic nervous system are brain and sacral region. Parasympathetic nervous system consists of cranio-sacral outflow and it concerned with the rest and digest response of the body. Its pre-ganglionic fibers are long and post-ganglionic fibers are short and ganglia are located near the effector organs. Its pre-ganglionic fibers and post ganglionic fibers both release acetylcholine as the neurotransmitter.