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level: Level 1

Questions and Answers List

level questions: Level 1

QuestionAnswer
What are the 2 divisions of the autonomic nervous systemSympathetic --> flight or fight response Parasympathetic --> eating, sexual arousal , urination , digestion etc.
What are gangliaCell bodies of neurons in the autonomic nervous system
What are some features of the parasympathetic ganglia and fibresGenerally the ganglia of the parasympathetic system are located close to, or sometimes within the structures controlled by the systems The preganglionic fibres tend to be long and postganglionic fibres tend to be short Also have cranio-sacral outflow
What are some features of the sympathetic ganglia and fibresPreganglionic fibres of the sympathetic branch leave the CNS from the thoracic and lumbar regions - so called thoraco-lumbar outflow Synapses between pre - and postganglionic neurons are mostly located in ganglia close to the spinal cord So preganglionic fibres are short and post-ganglionic fibres long
What neurotransmitter, do preganglionic neurons releaseAcetylcholine which acts on nicotinic ACh receptors on the postganglionic neurons which have ion channels
What transmitter is used in postganglionic neurons at sympatheticNoradrengenic so they use noradrenaline except sweat glands that use ACh
What transmitter is used in postganglionic neurons in parasympatheticPostganglionic parasympathetic neurons are usually cholinergic --> ACh
What is the function of chromaffin cellsAdrenal chromaffin cells release adrenaline which circulates in the bloodstream
What does the ANS do in the CVSHeart rate Force of contraction of the heart Peripheral resistance of blood vessels DOES NOT initiate the electrical activity in the heart
Where is the CVS control centre locatedMedulla oblongata --> located in the brain stem
What are some inputs of the parasympathetic system to the heartsynapse with postganglionic cells on epicardial surface or within walls of heart at SA and AV node Releases ACh Acts on M2 receptors Decreases heart rate Decreased AV node conduction velocity
What are some inputs of the sympathetic system to the heartInnervate SA node , AV node and myocardium Releases noradrenaline Acts on B1 adrenoreceptors Increases heart rate Increases force of contraction
Effect of sympathetic on pacemaker potentialsIncreases the slope Mediated by B1 receptors G-protein coupled receptors (Gs ) Increase cAMP → ligand to HCN channel Leads to the speeding up of pacemaker potentials
Effect of parasympathetic on pacemaker potentialsDecreases slope mediated by M2 receptors G-protein coupled receptors (Gi ) Increase K+ conductance and decrease cAMP
What is the simplified baroreceptor reflexBaroreceptor → Afferent → medulla → efferent → effector ( heart and blood vessels )
What happens to blood vessels when a1 adrenoreceptors are activatedVasoconstriction --> due to increased Ca2+ By PKA which leads to contraction
What happens to blood vessel when B2 adrenoreceptors are activatedActivating β2 adrenoceptors causes vasodilation