• Tehseen Iqbal RYK Medical & Dental College, Rahim Yar Khan, Pakistan


Autonomic stimuli, autonomic receptors, nucleus tractus solitarius, hypothalamus


The Autonomic Nervous System (ANS) and the endocrine system control the internal environment of the body. The organization of the ANS is on the basis of the reflex arc. Changes in chemical composition, blood pressure, osmotic pressure, stretch in viscera, and temperature are detected by autonomic receptors. The visceral afferent fibres are myelinated and they accompany the visceral motor fibres. The sensory autonomic neurons are pseudo-unipolar cells located in the dorsal root ganglia of somatic spinal nerves. Once the afferent fibres gain entrance to the spinal cord or the brainstem, they are thought to travel alongside the somatic afferent fibres to the autonomic centres in different parts of the brain. Information reaches the higher autonomic centres from viscera through an ascending system that involves the nucleus tractus solitarius, the parabrachial nucleus, the periaqueductal gray matter, and the hypothalamus. The hypothalamic paraventricular nucleus, pontine A5 cell group, rostral ventrolateral medulla, and medullary raphe nuclei send direct output to the preganglionic autonomic neurons. The amygdala, mesencephalic periaqueductal gray, caudal ventrolateral medulla, nucleus of the tractus solitarius, and medullary lateral tegmental field feed into these direct pathways.

Pak J Physiol 2023;19(4):1-2


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Bankenahally R, Krovvidi H. Autonomic nervous system: anatomy, physiology, and relevance in anaesthesia and critical care medicine. BJA Educ 2016;16(11):381–7.

Autonomic Nervous System. In: Barrett KE, Barman SM, Boitano S, Brooks HL. (Eds.) Ganong’s Review of Medical Physiology (25th ed.). McGraw-Hill Education; 2016.

Berne RM, Levy MN. Autonomic Nervous System. In: Medical Physiology (8th ed.). Philadelphia PA: Elsevier; 2018.

Autonomic Nervous System. In: Gray’s Anatomy; The Anatomical Basis of Clinical Practice. (42nd ed.). Elsevier Limited; 2020.p 394–5.

Snell RS, Splittgerber R. Autonomic Nervous System. In: Snell’s Clinical Neuroanatomy. (8th ed.). Wolters Kluwer/Lippincott Williams & Wilkins; 2019.

Hall JE, Hall ME. Autonomic Nervous System. In: Guyton & Hall Textbook of Medical Physiology (14th ed.). Elsevier; 2021.

Chaya MS, Nagendra HR. Long-term effect of yogic practices on diurnal metabolic rates of healthy subjects. Int J Yoga 2008;1(1):27–32.




How to Cite

Iqbal T. PHYSIOLOGY OF AFFERENT AND CENTRAL PARTS OF AUTONOMIC NERVOUS SYSTEM. Pak J Phsyiol [Internet]. 2023 Dec. 31 [cited 2024 Jun. 13];19(4):1-2. Available from: