BMS231 Physiology - Fall 2023 Lecture Notes PDF

F A C U L T Y O F P h a r m a c y F A L L 2 0 2 3 Faculty of Pharmacy Physiology AUTONOMIC NERVOUS SYSTEM 2 Dr. Doaa Abdel Wahed Lecturer of Physiology...

F A C U L T Y O F P h a r m a c y F A L L 2 0 2 3 Faculty of Pharmacy Physiology AUTONOMIC NERVOUS SYSTEM 2 Dr. Doaa Abdel Wahed Lecturer of Physiology Faculty of Medicine 2 Faculty of Pharmacy Intended Learning Outcomes - By the end of this lecture, you should be able to: 1. Identify types of autonomic ganglia. 2. Define the neurotransmitters of ANS. 3. List the different types of neurotransmitters in different parts of ANS. 4. Study types of receptors in autonomic nervous system. 3 Faculty of Pharmacy Autonomic Ganglia Faculty of Pharmacy Autonomic ganglia * Definition: - It is a collection of nerve cells outside the CNS and contains the nerve cells of the postganglionic neurons. Faculty of Pharmacy Autonomic Ganglia 6 Faculty of Pharmacy Types: 1-Lateral ganglia (paravertebral): - Form the sympathetic chain on both sides of the vertebral column. - Sites of relay of preganglionic sympathetic fibers only. Faculty of Pharmacy 2-Collateral ganglia: - It is present in the abdomen, near the big branches of the aorta. -It is the site of relay of preganglionic sympathetic and parasympathetic fibers but, mainly sympathetic. Faculty of Pharmacy 3-Terminal ganglia:. - It is present near or on the wall of effector organs. - It is the site of relay of preganglionic parasympathetic fibers only. Faculty of Pharmacy * Functions of Autonomic Ganglia: 1-Relay stations. (for preganglionic nerves and origin for postganglionic nerves) 2-Distributing centers. 3-Site of action of drugs. Faculty of Pharmacy Faculty of Pharmacy Preganglionic Vs postganglionic neurons ????? Types of autonomic ganglia ???? Functions of autonomic ganglia ????? 12 Faculty of Pharmacy 13 Faculty of Pharmacy Chemical Transmission at Autonomic Junctions Transmission at the synaptic junction between pre & post-ganglionic neuron & between the post- ganglionic neurons & effector organs is chemically mediated i.e. by neurotransmitters. The principal transmitter agents involved are: acetylcholine and nor-epinephrine. Usually, neurotransmitters exert their actions by combination with specific receptors in post- synaptic membrane. Faculty of Pharmacy * Chemical Divisions of the ANS: - On the basis of the chemical mediator released, the ANS can be divided into: Cholinergic system (release acetylcholine). Noradrenergic system (release noradrenaline). Faculty of Pharmacy * Acetyl choline: - Sites of release of acetylcholine: l- All preganglionic neurons (autonomic ganglia). 2- All parasympathetic post-ganglionic neurons. 3- Sympathetic post-ganglionic neurons which innervate sweat glands & blood vessels of skeletal muscles. Faculty of Pharmacy * Noradrenaline (Norepinephrine): - Sites of release of Noradrenaline: All Sympathetic post-ganglionic neurons except: - which innervate sweat glands & blood vessels of skeletal muscles. Faculty of Pharmacy Faculty of Pharmacy Adrenergic Receptors Types: α (alpha) and β (beta) adrenergic receptors. Are receptors in all the organs innervated by the postganglionic fibers of the sympathetic system. They are activated by noradrenaline. Faculty of Pharmacy Faculty of Pharmacy Cholinergic Receptors Types: Muscarinic (M) and Nicotinic (N). Muscarinic receptors are present in all the organs innervated by the postganglionic fibers of the parasympathetic system. Nicotinic receptors are present in the autonomic ganglia. They are activated by acetyl Choline. Faculty of Pharmacy Sympathetic Parasympathetic -Origin of Thoraco-Lumbar Cranio-Sacral preganglionic Thoracic (T1-T12) and lumbar Cranial (III, VII, IX & X) and fiber (L1-L3) segments of spinal sacral (S2-S4) segments of spinal cord. cord. -Origin of Sympathetic chain or Terminal ganglia or collateral postganglionic collateral ganglia. ganglia. fiber -Type of fiber Short cholinergic Long cholinergic preganglionic preganglionic and and short cholinergic long adrenergic(most) postganglionic. postganglionic. -Type of α (alpha) and β (beta) Nicotinic and muscarinic receptors adrenergic receptors. (cholinergic) receptors. Faculty of Pharmacy Faculty of Pharmacy Neurotransmitters in ANS ????? Site of release & receptors of Ach ????? Site of release & receptors of Nor-epinephrine ????? 24 Faculty of Pharmacy 25 Faculty of Pharmacy