Autonomic nervous system ANS vs. somatic NS Autonomic nervous system Autonomic nervous system Preganglionic fibers ̶ SNS, PNS ̶ Nikotinic receptor ̶ NN type and NM type ̶ Excitatory receptors Second messenger systems Autonomic nervous system Postganglionic fibers ̶ PNS ̶ Muscarinic receptor ̶ G-protein coupled ̶ Excitatory receptors (M1, M3, M5) ̶ Inhibitory receptors (M2, M4) Autonomic nervous system ̶ Postganglionic fibers ̶ SNS ̶ Adrenergic receptor ̶ G-protein coupled Autonomic nervous system Adrenergic receptor ̶ G-protein coupled ̶ Type α –Excitatory receptors ̶ Type β – Inhibitory receptors Autonomic nervous system FIGHTORFLIGHT RESTORDIGEST Brain control of ANS Eating behavior Urinary bladder control Secondary respiratory center Blood pressure control Respiratory center Temperature control Water balance Baroreceptor vs. Chemoreceptor Baroreflex I • Inotropic • Chronotropic • Dromotropic • Batmotropic effect Aferent pathway Parasympathetic pathway Sympathetic pathway BP=HR x SV x R R HR Sinus respiratory arytmie Something more… ̶ Oculocardial reflex ̶ Pressure on the eyebulbes decreases heart rate (activation of the vagus) ̶ It is used to suppress or stop tachycardia ̶ Low pressure baroreflex ̶ greater expansion of the left ventricle stimulates baroreceptors –vagus→medulla - inhibition of SNS – vasodilation, bradycardia – decrease of BP ̶ Diving reflex ̶ Cold water on the face causes respiratory arrest, peripheral vasoconstriction and bradycardia ̶ Coronary chemoreflex (Bezoldov-Hirtov-Jarisch reflex) ̶ Substances applied to the left coronary artery (veratridine, capsaicin, some contrast agents, substances produced by ischemic tissue) induce apnea and then hyperpnea, hypotension, bradycardia (vagal afferentation) Chemoreflex ANS and blood vessels EFECTORS RECEPTORS ADRENERGIC REACTION CORONARY A. α, β2 C, D SKIN A. α C SKELETAL MUSCLE α, β2 C, D BRAIN A. α C LUNGS A. α, β2 C, D ABDOMENAL A. α, β2 C, D VEINS α, β2 C, D GIT and ANS SNS PNS GIT - Enteric Nervous System ANS and urinary bladder PSN DETRUSOR CONTRACTION SPHINCTER RELAXATION SNS DETRUSOR RELAXATION SPHINCTER CONTRACTION Neurogenic bladder NAME COMMENTS Uninhibited bladder Lesion: above the pontine micturition center Signs: reduced awareness of bladder fullness, incontinence may occur Upper motor neuron bladder (Detrusor-sphincter dyssynergia) Lesion: between the pontine micturition center and sacral cord Signs: detrusor is usually spastic, simultaneous detrusor and urinary sphincter contractions increase pressures in the bladder, can lead to vesicoureteral reflux that and renal damage Mixed type A bladder Lesion: sacral cord lesion at the detrusor nucleus with sparring of the pudendal nucleus Signs: the detrusor muscle is flaccid, bladder is large, external urinary sphincter is spastic, incontinence uncommon Mixed type B bladder Lesion: sacral cord lesion at the pudendal nucleus with sparring of the detrusor nucleus Signs: the bladder is spastic and the external urinary sphincter is flaccid, incontinence is common Lower motor neuron bladder Lesion: sacral cord or sacral root while the thoracic sympathetic outflow to the lower urinary tract is preserved Signs: bladder is large and hypotonic, incontinence uncommon ANS and sexual function ANS and sexual function Thank you for your attention