AUTONOMIC NERVOUS SYSTEM [ANS] DISCUSSION Dr. Zahoor 1

Q.1 What is Autonomic Nervous System (ANS)? It’s the part of efferent division of PNS, but it is involuntary. Q2. What are the divisions of ANS? 1.Sympathetic Autonomic Nervous System 2.Parasympathetic Autonomic Nervous System Q3. Give the origin of Sympathetic ANS and Parasympathetic ANS? Sympathetic ANS thoracolumber outflow.: T 1 - T 12 and L 1 – L 2 /L 3 Parasympathetic ANS craniosacral outflow : cranial nerves: III, VII, IX, X sacral segments :S 2,3,4. 2

Q4. Draw diagram of Sympathetic and Parasympathetic ANS showing two neurons. [Preganglionic and Postganglionic neuron] 3

Q5.What is the difference between the length of Preganglionic and Postganglionic fiber in parasympathetic and parasympathetic ANS? sympathetic: Preganglionic fibers are shorter _ because they originate from the sympathetic cian: Postganglionic fibers are longer parasympathetic : Preganglionic fibers are longer Postganglionic fibers are shorter – near effecter organ- Q6. What is the chemical transmitter at Sympathetic ANS Preganglionic Fibers Chemical Transmitter - acetylcholine Postganglionic Fibers Chemical Transmitter – NE or NA Parasympathetic ANS Preganglionic Fibers Chemical Transmitter - acetylcholine Postganglionic Fibers Chemical Transmitter - acetylcholine 4

Q7. What is the action of sympathetic and parasympathetic ANS at the following places? 5

Q8. Name the adrenergic receptors where nor-epinephrine and epinephrine acts? Q9. What types of adrenergic receptors are present in the following? i. Heart β1 ii. Bronchi β2 iii. Blood vessel α 1 iv. Skeletal muscle blood vessel β2 v. GIT α 2 6

Q10. What is the chemical transmitter at postganglionic sympathetic nerve ending supplying sweat glands? acetylcholine Q11. Acetylcholine released at postganglionic parasympathetic nerve ending act on Muscarinic receptors at target or Effector organ. 7

Q12. What receptors are present at the ganglion in Sympathetic ANS and Parasympathetic ANS? Nicotinic receptors Q13. What is Adrenal Medulla? modified sympathetic ganglion. It does not give postganglionic fibers, but secretes epinephrine and nor-epinephrine directly into the blood, therefore, it is called Endocrine gland. Q14. What hormones are released by adrenal medulla? Adrenal medulla secretes - 80% Epinephrine - 20% Norepinephrine 8

9 SYMPATHETIC ANS 1.Origin 2.Organization 3.Chemical Transmitters 4.Actions 5.Receptors 6.Dominance 7.Drugs acting on adrenergic and muscarinic receptors COMPARISON OF SYMPATHETIC & PARASYMPATHETIC ANS PARASYMPATHETIC ANS Do the comparison yourself

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