Regulating Systems Week 3 Dr. Walid Daoud As. Professor

Divisions of Autonomic Nervous System ParasympatheticSympathetic Cranio-sacral III, VII, IX, X + S 2,3,4 Localized.Thoraco-lumbar All T + upper 3 L WidespreadOriginDistribution AnabolicCatabolicFunction Cholinergic: Acetyl choline Adrenergic: adrenaline and noradrenaline Chemical transmitter

Functions of Sympathetic N.S. ___________________________ 1-Head and neck:. Eye:. Eye: - Motor to dilator pupillae muscle. - Motor to dilator pupillae muscle. - Relaxation of ciliary muscle. - Relaxation of ciliary muscle. - Vasoconstriction of conjunctival vessels. - Vasoconstriction of conjunctival vessels. - Decrease tears secretion. - Decrease tears secretion.

Functions of Sympathetic N.S. __________________________. Skin: - Secretory to sweat glands. - Secretory to sweat glands. - Vasoconstriction of cutaneous vessels. - Vasoconstriction of cutaneous vessels. - Contraction of piloerector muscle - Contraction of piloerector muscle. Salivary glands: Trophic secretion of saliva. Trophic secretion of saliva.. Cerebral circulation; Increase cerebral blood flow due to an Increase cerebral blood flow due to an increase in arterial blood pressure. increase in arterial blood pressure.

Functions of Sympathetic N.S. ___________________________ 2- Thoracic viscera:. Heart:. Heart: - Increase all properties of the heart. - Increase all properties of the heart. - Vasodiltation of coronary blood vessels. - Vasodiltation of coronary blood vessels.. Lungs:. Lungs: - Dilatation of all bronchial tree. - Dilatation of all bronchial tree. - Vasoconstriction of pulmonary vessels. - Vasoconstriction of pulmonary vessels.

Functions of Sympathetic N.S. ____________________________ 3- Abdominal viscera:. GIT: Inhibition of smooth muscles of. GIT: Inhibition of smooth muscles of stomach to proximal part of large intestine. Vasoconstriction to their arterioles. stomach to proximal part of large intestine. Vasoconstriction to their arterioles. Motor to sphincters. Motor to sphincters.. Liver: Stimulation of glycogenolysis.. Liver: Stimulation of glycogenolysis.. Spleen: Contraction of splenic capsule.. Spleen: Contraction of splenic capsule.. Adrenal medulla: Secretes adrenaline and noradrenaline.. Adrenal medulla: Secretes adrenaline and noradrenaline.

Functions of Sympathetic N.S. ____________________________ 4- Pelvic viscera:. GIT: Inhibition of plain muscles of distal. GIT: Inhibition of plain muscles of distal part of large intestine and rectum and part of large intestine and rectum and contraction of internal anal sphincter. contraction of internal anal sphincter.. Urinary bladder: Inhibition of the wall and contraction of internal urethral sphincter.. Urinary bladder: Inhibition of the wall and contraction of internal urethral sphincter.. Male genital organs: Contraction of vas. Male genital organs: Contraction of vas deference, seminal vesicle and prostate deference, seminal vesicle and prostate and vasoconstriction of blood vessels. and vasoconstriction of blood vessels.

Functions of Parasympathetic N.S. _____________________________ 1- Head and neck:. Oculomotor nerve III:. Oculomotor nerve III: - Motor to constrictor pupillae muscle. - Motor to constrictor pupillae muscle. - Contraction of ciliary muscle. - Contraction of ciliary muscle.. Facial nerve VI:. Facial nerve VI: - Secretomotor and vasodilator to the - Secretomotor and vasodilator to the submandibular and sublingual salivary submandibular and sublingual salivary glands and lacrimal glands. glands and lacrimal glands.. Glossopharyngeal nerve IX:. Glossopharyngeal nerve IX: Secretomotor and vasodilator to parotid. Secretomotor and vasodilator to parotid.

Functions of Parasympathetic N.S. _____________________________ 2-Thoracic & abdominal viscera: Vagus X. Heart: - Inhibit all properties of atrial muscles only. - Inhibit all properties of atrial muscles only. - Decrease coronary blood flow and O2 used - Decrease coronary blood flow and O2 used. Lungs: - Constriction of airway & dilatation of vessels - Constriction of airway & dilatation of vessels - Stimulation of bronchial glands. - Stimulation of bronchial glands.. GIT and gall bladder: - Motor to wall & inhibitory to sphincters, down to proximal part of large intestine. - Motor to wall & inhibitory to sphincters, down to proximal part of large intestine.

Functions of Parasympathetic N.S. _____________________________ 3- Pelvic viscera:. Defecation.. Defecation.. Micturation.. Micturation.. Erection in males.. Erection in males.. Vasodilatation of female genital organs.. Vasodilatation of female genital organs.

Chemical Transmission at Autonomic Junctions ____________________________ Transmission at the synaptic junctions is chemically mediated between: - Pre- and postganglionic neurons. - Pre- and postganglionic neurons. - Postganglionic neurons and autonomic - Postganglionic neurons and autonomic effector organs. effector organs. Chemical transmitters: Acetylcholine and noradrenaline. Acetylcholine and noradrenaline.

Acetylcholine ____________________________ Chemical transmitter released by cholinergic fibers to stimulate cholinergic receptors. Sites of secretions: - All preganglionic fibers: Sympathetic Parasympathetic Parasympathetic Suprarenal medulla Suprarenal medulla - All postganglionic parasympathetic fibers. - Postganglionic sympathetic fibers to sweat glands & blood vessels of skeletal muscles.

Acetylcholine __________________________ Synthesis: Choline Choline Acetyl – CoA → Acetylcholine Acetyl transferase Acetyl transferase Acetylcholine is stored in clear vesicles in the termination of cholinergic fibers

Acetylcholine ____________________________ Release: The action potential causes release of acetylcholine from the vesicles by exocytosis. Removal: Acetylcholine Acetylcholine Acetylcholine → Choline + Acetate esterase esterase

Noradrenaline (Norepinephrine) ____________________________ Chemical transmitter released by adrenergic fibers to stimulate adrenergic receptors. Sites of secretion: Postganglionic sympathetic fibers except: - Secretory fibers to sweat glands. - Vasodilator cholinergic fibers to blood vessels of skeletal muscles. vessels of skeletal muscles.

Noradrenaline (Norepinephrine) ____________________________ Synthesis: In terminal ending of adrenergic nerve fiber and secreted from adrenal medulla with adrenaline. Release: Nerve impulse stimulate adrenergic fibers to release adrenaline by exocytosis.

Noradrenaline (Norepinephrine) ____________________________ Removal: 1- Re-uptake into the adrenergic nerve endings (50-80%). endings (50-80%). 2- Diffusion away from the nerve ending into body fluids. 3- Destructed by enzymes:.Monoamine oxidase (MAO) on mitochondria.Catechol-0-methyl-transferase (COMT) in all tissues

Receptors of Effector Organs ___________________________ 1- Cholinergic receptors:. Muscarinic receptors:. Muscarinic receptors: - All postganglionic parasympathetic NS - All postganglionic parasympathetic NS - Postganglionic cholinergic sympathetic NS - Postganglionic cholinergic sympathetic NS. Nicotinic receptors: Autonomic ganglia.. Nicotinic receptors: Autonomic ganglia. 2- Adrenergic (Alpha & Beta) receptors: - On surface of effector organ (postsynaptic). - On surface of effector organ (postsynaptic). - On postganglionic nerve ending (presynaptic). - On postganglionic nerve ending (presynaptic).

Actions of Post-synaptic Adrenergic Receptors ________________________________________ Alpha receptors: 1-Vasoconstriction. 2-Contraction of plain muscles of: Dilator pupillae muscle, sphincters of GIT, Dilator pupillae muscle, sphincters of GIT, spleen, internal urethral sphincter, seminal vesicles and vas deferens. spleen, internal urethral sphincter, seminal vesicles and vas deferens. 3-Inhibition of plain muscles of intestine.

Actions of Post-synaptic Adrenergic Receptors ________________________________________ Beta receptors: 1-Vasodilatation of skeletal blood vessels (β2) 2-Inhibition of plain muscles of: Bronchi, GIT, urinary bladder and uterus. Bronchi, GIT, urinary bladder and uterus. 3-Cardiac acceleration and increased force of contraction of the heart (β1). contraction of the heart (β1). 4-Lipolysis (β1).

Comparison Between Sympathetic and Parasympathetic Functions ____________________________ See Page 16 and 17 in the Chapter of Regulating Systems in the Chapter of Regulating Systems