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Autonomic Nervous System. Dr Dileep Verma Associate Professor Deptt of Physiology KGMU. Lecture-2 :Topics. Neurotransmitters of ANS Receptors of ANS - Adrenergic - Cholinergic.
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Autonomic Nervous System Dr DileepVerma Associate Professor Deptt of Physiology KGMU
Lecture-2 :Topics • Neurotransmitters of ANS • Receptors of ANS - Adrenergic - Cholinergic
Learning Objectives • List different types of adrenergic & cholinergic receptors with their location • Various autonomic neurotransmitters. • Mechanisms of neurotransmitter release in the sympathetic and parasympathetic divisions.
Autonomic nervous System • Neurotransmitters of ANS • Neurotransmitters of sympathetic nervous system • Neurotransmitters of parasympathetic nervous system
Sympathetic Nervous System Neurotransmitters at- • Preganglionic nerve endings • Postganglionic nerve endings • Target tissue
Sympathetic Nervous System Neurotransmitters at- • Preganglionic nerve endings • Acetylcholine (ACh) • Postganglionic nerve endings • Norepinephrine (NE) • Acetylcholine (ACh)
Sympathetic Nervous System Neurotransmitters at- Target tissue • Epinephrine (Ep) • Norepinephrine (NE) • Acetylcholine (Ach)
Parasympathetic Nervous System Neurotransmitters at- • Preganglionic nerve endings • Acetylcholine (ACh) • Postganglionic nerve endings • Acetylcholine (ACh)
Autonomic nervous System Receptors of ANS • Receptors of Sympathetic Nervous System • Receptors of Parasympathetic Nervous System
Autonomic nervous System Receptors of ANS • Receptors of Sympathetic Nervous System • Receptors of Parasympathetic Nervous System
Autonomic nervous System Receptors of ANS • Receptors of Sympathetic Nervous System • Adrenergic Receptors • Cholinergic Receptors • Receptors of Parasympathetic Nervous System • Cholinergic Receptors
Adrenergic Receptors • Alpha adrenergic • Alpha-1 (a1)- Excitatory • Alpha-2 (a2)- Inhibitory • Beta adrenergic • Beta-1(b1)- Excitatory • Beta-2 (b2) -Inhibitory • Beta-3 (b3)- Excitatory
Alpha adrenergic receptor (a) • Alpha-1 (a1)- Excitatory • Vascular smooth muscles • Skin • Splanchnic region • GI wall • Sphincters • Radial muscle of iris • Alpha-2 (a2)- Inhibitory • Presynaptic nerve terminal • Platelets • GI wall
Beta adrenergic receptor (b) • Beta-1(b1)- Excitatory • SA Node • AV Node • Myocardium • Beta-2 (b2) –Inhibitory • Vascular smooth muscles • Skeletal muscle • Bronchial smooth muscles • GI Wall • Beta-3 (b3)- Excitatory • Adipose tissue
Cholinergic Receptor Cholinergic Receptors- 2 types • NicotinicReceptors (N) • Nicotinic Neuronal (NN) Type • Nicotinic Muscular (NM) Type • Muscarinic Receptors (M) • M1 to M7
Nicotinic Neuronal (NN) Type • Location - Autonomic ganglia • Activated by- • Ach • Nicotine • Effect – Excitatory or Inhibitory • Blocked by- Hexamethonium
Nicotinic Muscular (NM) Type • Location - Neuromuscular Junction • Activated by- • Ach • Nicotine • Effect – Always Excitatory • Blocked by- Curare
Muscarinic receptor • Location - • Myocardium • Glands • Smooth muscle • Activated by- • Ach • Muscarine • Effect – Inhibitory/Excitatory • Blocked by- Atropine
At Sweat Gland • Neurotransmitter-Acetylcholine • Receptors- Muscarinic • At the adrenal cortex • no postsynaptic neuron • Neurotransmitter-Acetylcholine • Receptors- Nicotinic
1- Sympathetic postganglionic fibres to sweat gland secrete-- Acetylcholine Norepinephrine Epinephrine Serotonin
2-Acetylcholine through nicotinic receptors causes-- Constriction of pupil Secretion of saliva Decreases the heart rate Contraction of skeletal muscle
3-.Stimulation of alpha adrenergic receptors results in- Pupillary dilatation Glycogenolysis Inhibit intestinal motility All of the above
4. a1adrenergic receptors are located on/in Presynaptic nerve terminal Platelets GI wall Radial muscle of iris
5-Which is true about b3adrenergic receptors ? Located on adipose tissue More sensitive to epinephrine Stimulate glycogenesis Inhibits lipolysis