The Autonomic Nervous System-Lecture 12 Exam 3 Flashcards
Two Branches of the Autonomic Nervous System
Sympathetic & Parasympathetic
Major Function of the Sympathetic Branch
-Dominates in stressful situations
-“Fight-or-Flight”
Major Function of the Parasympathetic Branch
-Dominates during quiet activities
-“Rest and digest”
Different Types of Autonomic Control
Dual Innervation, Single Innervation, & Receptor Determines Response
Dual Innervation
-Gas Pedal, Break Pedal
-Structure receives input from both branches of the ANS
-Sympathetic (excitatory), Parasympathetic (inhibitory)
-Ex: sympathetic stimulation increases heart rate & parasympathetic decreases heart rate
Single Innervation
-Step on Gas, Let off Gas
-Structure receives input from only sympathetic branch
-Ex: sympathetic branch innervates sweat glands & most blood vessels
Receptor Determines Response
-Epinephrine binding to different receptors lead to different responses
-(a) receptors = blood vessel constricts
-(B2) receptors = blood vessel dilates
Sympathetic Branch of ANS: Where does the preganglionic neuron originate in the CNS?
The thoracic & upper lumbar spinal cord
Sympathetic Branch of ANS: Where is the location of the ganglia?
Lie just outside the spinal cord
Sympathetic Branch of ANS: Length of the preganglionic & postganglionic axons?
-Preganglionic (short)
-Postganglionic (long)
Sympathetic Branch of ANS: The neurotransmitters released from the preganglionic & postganglionic neurons & the receptors the NTs will bind to?
-Preganglionic release ACh & bind to nicotinic receptors
-Postganglionic release NE & bind to adrenergic receptors
Parasympathetic Branch of ANS: Where does the preganglionic neuron originate in the CNS?
The Brain Stem & Sacral Spinal Cord
Parasympathetic Branch of ANS: Location of the ganglia?
Near or embedded in the target organ
Parasympathetic Branch of ANS: Length of the preganglionic & postganglionic axons?
-Preganglionic (long)
-Postganglionic (short)
Parasympathetic Branch of ANS: Neurotransmitters released from the preganglionic & postganglionic neurons & the receptors the NTs will bind to?
-Preganglionic release ACh & bind to nicotinic receptors
-Postganglionic release ACh & bind to muscarinic receptors
ACh (receptors, receptor locations, & termination/inactivation of NT activity)
-Receptors: muscarinic (cholinergic)
-Termination/Inactivation: Broken down by AChE into acetate + choline
-Acetate diffuses away
-Choline reuptake into cell
NE (receptors, receptor locations, & termination/inactivation of NT activity)
-Receptors: alpha & beta (adrenergic)
-Termination/Inactivation: Diffuses away and/or reuptake into varicosity
-Repackaged into vesicles
-Broken down by MAO (monoamine oxidase inhibitor)
Axon Terminal
The specialized end of an axon that releases neurotransmitters to communicate with other cells via synapses
Axon Varicosity
Enlarged pre-synaptic boutons that have the key function of neurotransmitter release and indicate locations of synapses under normal physiological conditions
Why are varicosities useful in the autonomic nervous system?
Neurotransmitter release
