introduction to autonomic physiology Flashcards
the function of the sympathetic nervous system
orchestrates the stress response and energy consumption associated with “fight or flight” reactions, but also very important ongoing activity
the function of the parasympathetic nervous system
regulates many functions, some of which are restorative and energy conserving “rest and digest”
functions of the autonomic nervous system
maintenance of homeostasis by…
Skin: thermoregulation by controlling contraction and relaxation of smooth muscle in the vasculature
Liver/ pancreas: metabolism of glucose
Lungs: ventilation of control partial pressures and pH
Kidneys: fluid balance
Heart and vasculature blood pressure by contraction and relaxation of smooth muscle in vasculature
functions of the autonomic nervous system
maintenance of homeostasis by…
Skin: thermoregulation by controlling contraction and relaxation of smooth muscle in the vasculature
Liver/ pancreas: metabolism of glucose
Lungs: ventilation of control partial pressures and pH
Kidneys: fluid balance
Heart and vasculature blood pressure by contraction and relaxation of smooth muscle in the vasculature
what are the three components of the negative feedback loop of homeostasis
sensors, comparator and effectors
Anatomy of ANS
sympathetic nervous system
Myelinated pre-ganglionic fibers (neurons) - short
Pre-ganglionic fibers synapse in paravertebral or
prevertebral ganglia
Unmyelinated post-ganglionic fibers (neurons) -long
anatomy of ANS
parasympathetic nervous system
Myelinated pre-ganglionic fibers (neurons) - long
Pre-ganglionic fibers synapse in or on target tissues/organs
Unmyelinated post-ganglionic fibers (neurons) -short
neurotransmission in the Sympathetic nervous system
Preganglionic neurons
Neurotransmitter = Acetylcholine
Post-synaptic receptor = Nicotinic acetylcholine receptor
Post-ganglionic neurons
Neurotransmitter = Acetylcholine
Post-synaptic receptor = Muscarinic acetylcholine receptor
Neurotransmitter = Noradrenaline
Post-synaptic receptor = α1/ α2 adrenoreceptor; β1/β2adrenoreceptor
Neurotransmission of the parasympathetic nervous system
Preganglionic neurons
Neurotransmitter = Acetylcholine
Post-synaptic receptor = Nicotinic acetylcholine receptor
Post-ganglionic neuronsNeurotransmitter = Acetylcholine
Post-synaptic receptor = Muscarinic acetylcholine receptor
Nicotinic acetylcholine receptors are …
-present in the ganglia
-ligand-gated ion channels
Muscarinic acetylcholine receptors are…
-present in the effector cells
-g protein-coupled receptors
a-adrenoreceptor order
noradrenaline>adrenaline>isoprenaline
b-adrenoreceptor order
isoprenaline>adrenaline>noradrenaline
summary
The autonomic nervous system, with it’s two branches (sympathetic and parasympathetic) mediateinvoluntary effector responses in homeostatic control loops
The sympathetic nervous system is thoracolumbar in origin and has short pre-ganglionic and long postganglionic neurons
The parasympathetic nervous system is craniosacral in origin and has long pre-ganglionic and short postganglionic neurons
Both sympathetic and parasympathetic nervous system preganglionic neurons release acetylcholine which acts on nicotinic acetylcholine receptors
Sympathetic nervous system post-ganglionic neurons release either acetylcholine or noradrenaline which act on muscarinic acetylcholine receptors or a range of adrenoreceptors, respectively
