Model Answers Of Self Assessment PDF

Self assessment 1- What is the main function of autonomic ganglia? Distributing centers: The ganglion gives many postganglionic fibers for every preganglionic fiber it receives. Therefore, autonomic fibers reach the viscera all over the body although they arise from limited areas of spinal cord and...

Self assessment 1- What is the main function of autonomic ganglia? Distributing centers: The ganglion gives many postganglionic fibers for every preganglionic fiber it receives. Therefore, autonomic fibers reach the viscera all over the body although they arise from limited areas of spinal cord and brain stem. 2- What are the functions of sympathetic nerve to the abdomen? 1) Vasoconstrictor to blood vessels of stomach, small intestine. proximal part of large intestine. liver. kidney and pancreas. 2) Inhibitory to the smooth muscles of the stomach, small intestine and proximal part of the large intestine. The nerve is motor to their sphincters. 3) Glycogenolytic to the liver, i.e. it hydrolyses glycogen into glucose. 4) Secretory to the suprarenal medulla where adrenaline(80%) and noradrenaline(20%) are liberated. 3- What is the response of the following effector organs to adrenergic(=sympathetic) impulses: Eye ciliary muscle: relaxation Helping accommodation for far vision. Bronchial muscles: relaxation bronchodilatation Coronary blood vessels Vasodilatation (increase of coronary blood flow) Gall bladder Relaxation of the wall and contraction of the sphincter of Oddi Retention of bile. Stomach sphincter contraction skin sweet gland No response because sweet glands are supplied with sympathetic cholinergic fibers. submandibular salivary glands Secretion of saliva which is little, viscid, rich in enzyme. Urinary bladder wall. Relaxation helping urine retention. 4- What is the autonomic nerve supply to the blood vessels of the skeletal muscles? Sympathetic fibers. 5- Comments on the following: Parasympathetic nerves: a)Play an important part in the vasodilatation in skeletal muscle during exercise. False.skeletal muscles have no parasympathetic supply. b) Liberate acetylcholine at both preganglionic and postganglionic nerve ending. True. All parasympathetic fibers are cholinergic. 6- What are the function of sacral part of autonomic system? This part is parasympathetic. So ,its functions are: 1- Erection of penis and clitoris (vasodilatation). 2- Micturition i.e passage of urine from urinary bladder o the outside the body.parasympathetic nerves are motor to bladder wall and inhibitory to internal urethral sphincter. 3-Defecation, i.e. passage of faeces from rectum to outside the body. Parasympathetic is motor to rectal wall but inhibitory to internal anal sphincter. 4- Secretion from seminal vesicles and prostate. 7- Contrast the effect of sympathetic and parasympathetic stimulation on the eye and its lids? Structure Sympathetic Parasympathetic 1- Blood vessels Vasoconsrictor Vasodilator 2-Dilator pupillae Contraction No effect muscle Pupillodilation. 3- Constrictor pupillae No effect Contraction muscle. Pupilloconstriction. 4-Ciliary muscle of Accommodation for Contraction lids far vision Accommodation for near vision. 6- Lacrimal gland Mild secretion of tears Strong secretion of tears. 8-What is the nerve supply to sweet gland? Postganglionic sympathetic cholinergic fibers, i.e releasing acetyl choline. 9-What are sites of formation of adrenaline? 1-Suprarenal medulla. 2-Postganglionic sympathetic nerve endings. 10-Are all sympathetic fibers adrenergic? No. Some sympathetic fibers are cholinergic ,i.e. liberating acetyl e.g those to sweet glands, to suprarenal medulla and all preganglionic sympathetic nerves. 11- What are adrenergic receptors? Those are receptors responding to noradrenaline and adrenaline. they are present on the effector cells facing all postganglionic sympathetic fibers(except those to sweat glands),i.e adrenergic fibers. They are of 2 types: 1) Alpha adrenergic receptors: responding to noradrenaline and adrenaline. They are mainly excitatory.e.g. they produce vasoconstriction. However, there are exceptions, e.g. they relax intestinal muscles. 2)Beta Adrenergic receptors: responding to adrenaline. they are mainly inhibitory, e.g. they produce vasodilatation. However, there are exceptions, e.g.they increase the heart rate. So, adrenaline stimulates both alpha and beta adrenergic receptor while noradrenaline stimulates alpha receptors only. 12- Why does adrenaline have double action(e.g. vasodilatation and vasoconstriction) but not noradrenaline(it is vasoconstriction)? Because adrenaline stimulates both alpha and beta receptors while noradrenaline stimulates only alpha receptors. Best of luck DR. khadeejh alsolami