Physiology Lecture (8) PDF

Physiology Functions of parasympathetic NS LECTURE (8) DR. El-Sawy 0  Physiology Functions of parasympathetic...

Physiology Functions of parasympathetic NS LECTURE (8) DR. El-Sawy 0  Physiology Functions of parasympathetic NS Nerve Origin Relay  Occulo-Motor  Edinger Westphal  Ciliary 3 nucleus in midbrain  Greater Superficial  Spheno-Palatine 7 Petrosal  Superior Salivary (Facial) nucleus in pons  Chorda tympani  Sub-Mandibular  Glossopharyngeal  Inferior Salivary  Otic ganglion 9 nucleus in medulla.  Vagus  Dorsal Motor nucleus  Terminal ganglion 10 of vagus in medulla. Pelvic  Pelvic  Sacral 2 , 3 , 4  Terminal ganglion DR. El-Sawy 1  Physiology Functions of parasympathetic NS 3 : ( Occulomotor ) : Motor to : 1. Constrictor pupillae muscle → Pupillary Constriction ( Miosis ) 2. Ciliary muscle → accommodation to Near Vision 7 : (Facial ) : has 2 branch : Gland Lacrimal Gland Tears Greater superficial petrosal Mucous Nose, pharynx, membrane soft palate Mucous Sublingual & True salivary secretion Gland large, watery, poor in enzymes Submandibula Chorda Tympani & rich in electrolytes. r 2 Ant /3 of Mucous membrane tongue Mucous 9 : (Glossopharyngeal ) : True salivary secretion Gland Parotid large, watery, poor in enzymes & rich in electrolytes. Mucous Post. 1/3 of membrane tongue Mucous All Cause :  VD  ↑Secretion DR. El-Sawy 2  Physiology Functions of parasympathetic NS NB :  In near vision e.g. during reading, parasympathetic stimulation is important to decrease the size of pupil to decrease the amount of light entering the eye and increases the lens power to focus the image of the object on the retina of the eye. Heart a. It decrease all cardiac properties :→↓ effectiveness of heart as a pump. Rhythmicity Excitability  Vagus supply atria only (doesn't Conductivity supply ventricles). Contraction b. Coronary vessels: Direct effect → vasodilatation. Indirect effect → vasoconstriction (due to inhibition of cardiac work with less metabolites accumulation). Lung stimulation of bronchial muscles Pulmonary V.d → Broncho-constriction stimulation of bronchial mucus glands → ↑ mucus secretion DR. El-Sawy 3  Physiology Functions of parasympathetic NS Functions: Contraction of wall ↑Bile flow Relaxation of sphincter of oddi Stimulation of emptying Stimulation of all glands : Stimulation of pancreatic secretion. a. Gastric glands b. Brunner's gland in duodenum Contraction of walls. Relaxation of sphincters. Vasodilatation. Stimulation of emptying. DR. El-Sawy 4  Physiology Functions of parasympathetic NS Functions : Contraction of wall. Contraction of wall Relaxation of internal urethral Relaxation of internal anal sphincter sphincter. Stimulation of micturition. Stimulation of defecation. VD → erection of penis. VD → Erection of clitoris. Stimulation of glands → secretion. Stimulation of glands → secretion.  The pelvic nerve is named as the nervous erigenus. DR. El-Sawy 5  Physiology Functions of parasympathetic NS 1. The external anal and urethral sphincters are voluntary ms supplied by the somatic spinal pudendal nerve. 2. Most organs have a double nerve supply sympathetic & parasympathetic N.S. 3. Some organs are supplied only by one division of autonomic N.S. Sympathetic supply only Parasympathetic supply only 1) Dilator pupillae muscle 1) Constrictor pupillae muscle 2) Muller's muscle. 2) Upper esophagus. 3) Cutaneous effectors 3) Glands of stomach. 4) Ventricles of heart. 5) Spleen 6) Adrenal medulla 4. The relation between sympathetic and parasympathetic NS may be: One system increases the function and the 2nd decreases the functions Antagonistic e.g. heart rate, sympathetic NS increases HR and parasympathetic N.S. decreases HR During salivary secretion: Synergistic  Sympathetic secretes enzymes.  Parasympathetic secretes water and electrolytes. During sexual intercourse: Cooperative  Parasympathetic NS causes erection.  Sympathetic NS causes ejaculation. DR. El-Sawy 6