Autonomic Nervous system

Question 1

1. Describe the general structure of the autonomic portion of the nervous system.

Answer 1

1. It is part of the peripheral nervous system, generally involving a preganglionic neuron & a postganglionic neuron. The preganglionic for SNS exits the spinal cord in the T1-L2 region. The preganglionic for the PNS exits the spinal cord in the S2-S4 region plus the brain stem along with cranial nerves III, VII, IX and X. They postganglionic neurons innervate visceral structures such as smooth muscle, cardiac muscle and glands.

Question 2

2. Name the 2 divisions of the A.N.S.

Answer 2

2. Parasympathetic (PNS, rest & relaxation) and Sympathetic (SNS, fight or flight)

Question 3

3. Define neurotransmitter. Name the neurotransmitters of the A.N.S.

Answer 3

3. Neurotransmitters are chemicals that carry impulses across synapses. Acetylcholine is the neurotransmitter released from the preganglionic neurons in both PNS and SNS AND for the postganglionic neuron in PNS. Norepinephrine is the neurotransmitter released by the postganglionic neuron in SNS.

Question 4

4. Describe the anatomical pathway of the sympathetic and parasympathetic divisions.

Answer 4

4. Covered in #1

Question 5

5. Explain the role of the hypothalamus and its relationship to the sympathetic and parasympathetic divisions.

Answer 5

5. Hypothalamus is the control center for Autonomic Nervous System.

Question 6

6. Describe the effects of parasympathetic and sympathetic stimulation {heart, lungs, digestion, pupil, sweat glands, adrenal medulla, cutaneous blood vessels, abdominal blood vessels, and skeletal muscle blood vessels}.

Answer 6

6. Heart: PNS decreases rate & strength of contraction, SNS is opposite Lungs: PNS decreases size of airways & SNS is opposite Digestion: PNS increases movement & secretions in all of digestion & SNS is opposite Pupil: PNS constricts pupil, SNS dilates pupil. Sweat glands: Only innervated by SNS and it causes you to sweat Adrenal medulla: Only innervated by preganglionic neurons in SNS and it causes the adrenal medulla to release epinephrine & norepinephrine to exaggerate the fight or flight response. Cutaneous & abdominal blood vessels: Only innervated by SNS and it causes them to constrict to decrease blood flow. Skeletal muscle blood vessels: Only innervated by SNS and it causes them to dilate to increase blood flow.