Transcript Slide 1
PNS Nerves Somatic NS Voluntary Effectors = skeletal muscles Autonomic NS Involuntary Sympathetic Motor System Parasympathetic Motor System “Fight or Flight” “Rest and Repose” Somatic Nervous System • Contraction of _________ muscles • Skeletal muscle = somatic effector • All _____________ motor pathways outside of CNS • Neurotransmitter = ______ Reflexes • All voluntary motor pathways outside of CNS • Reflexes – Action resulting from nerve impulse passing over a reflex arc – Predictable response to stimuli – ____________ Reflex • Visceral • Contraction of smooth or cardiac muscle • Secretion of glands – ____________ Reflex • Contraction of skeletal muscles Somatic Reflexes • Contraction of skeletal muscles • Reflexes deviate from normal in certain conditions • Reflex testing is valuable diagnostic tool – Patellar Reflex: extension of lower leg – Achilles Reflex: extension of foot – ____________________ Reflex: extension of big toe • Present until age 1.5 • If present after, indicates damage to corticospinal fibers – Plantar Reflex: flexion of all toes and slight turning in of foot – Corneal Reflex: wink when touch cornea – Abdominal Reflex: stroke side of abdomen causes drawing in of abdominal wall Knee-Jerk (Patellar) Reflex Autonomic Nervous System • ________________/Visceral body functions – Cardio, resp, dig, urogen • Maintain homeostasis by: regulating heartbeat, smooth muscle contraction, glandular secretions • Conduct impulses from CNS to autonomic effectors • Two divisions – Sympathetic – Parasympathetic Autonomic Conduction Pathway Parasympathetic Nervous System • “Feed-or-Breed” • “Rest-and-Repose” • Counteracts Sympathetic Sympathetic Nervous System • “Fight-or-Flight” • Allows body to function under stress ANS Neurotransmitters • Norepinephrine (adrenaline) – ________________ fibers • release norepinephrine in postsynaptic sympathetic neurons • Acetylcholine (ACh) – ________________ fibers • release ACh in presynaptic sympathetic neurons • release ACh in pre and post parasympathetic neurons Norepinephrine • Affects visceral effectors by binding to adrenergic receptors – Alpha receptor: blood vessels __________ – Beta receptor: blood vessels ____________ • Inhibiting action of norepinephrine – MAO (monoamine oxidase): enzyme that breaks up norep that are taken up by synaptic knobs ACh • Binds to cholinergic receptors – Nicotinic receptors – Muscarinic receptors • Inhibiting action of Ach – acetylcholinesterase