PH1124 - Autonomic Nervous System Flashcards
(29 cards)
what is the autonomic nervous system?
- the part of the nervous system responsible for control of the bodily functions not consciously directed, such as breathing, the heartbeat, and digestive processes
what is the autonomic nervous system split into? (2)
- sympathetic nervous system
- parasympathetic nervous system
How is visceral pain felt?
Sensory neurons to the spinothalamic tract to the thalamus to the cerebral cortex the pain is difficult to localise so is referred to somatic regions of the body.
Why is there poor localisation of referred pain?
the afferents from the viscera synapse on the same neurons of dorsal horn as the A beta fibres from skin mechanoreceptors this is then projected via anterolateral column.
What is the role of the amygdala?
Main limbic region for emotions so stimulates sympathetic activity especially previously learned fear behaviour.
What is the reticular formation?
a nerve network in the brainstem that plays an important role in the influence of the autonomic function.
what is the difference between ANS neurons and sensory/motor neurons?
- ANS neurons require two neurons which synapse in the ganglia
what is the difference between the ganglionic fibres in the parasympathetic and sympathetic nervous system? (2)
Sympathetic- Short preganglionic fibres and long post ganglionic fibres.
Parasympathetic- long preganglionic fibres and short post ganglionic fibres.
what are ganglia?
- clusters of cell bodies in the PNS that contain many synapses
Why is the adrenal medulla an exception?
Only one neuron from spinal cord to it. And no innervation from parasympathetic nervous system.
Where does the neurons in the adrenal medulla synapse?
Synapses in the gland.
which fibres are myelinated, pre or post ganglionic?
- pre
what are nicotinic receptors?
- fast action excitatory ion channels that uses acetylcholine
what are muscarinic receptors?
- G-protein coupled receptors that use acetylcholine
M1-M3 in parasympathetic targets and M1/M2 inhibitory.
M3 excitatory.
what type of receptors are noradrenergic/adrenergic receptors?
- G-protein linked receptors
what are the post synaptic noradrenergic/adrenergic receptors and are they inhibitory or excitatory? (5)
- α1; excitatory; post-synaptic receptor
- α2; inhibitory; pre-synaptic receptor
- β1; excitatory; post-synaptic receptor
- β2; inhibitory/excitatory; post-synaptic receptor
- β3; excitatory.; post-synaptic receptor
What is the main difference between the sympathetic and parasympathetic nervous system ?
The parasympathetic nervous system restores the body to a calm and composed state and prevents it from overworking. The sympathetic nervous system, on the other hand, prepares the body for fight and flight response.
what would a nicotinic agonist cause to Ach ganglia?
- short term hypertension, palpitations, secretions and GI stimulation
what would an nicotinic antagonist cause to Ach ganglia?
- hypotension, loss of cardiac reflexes, inhibition of secretions, GI paralysis
what would a muscarinic agonist cause to parasympathetic effectors? (3)
- M1; secretion of gastric acid
- M2; slowing of the heart
- M3; contraction of smooth muscle
what would a muscarinic antagonist cause to parasympathetic effectors? (3)
- M1; reduced secretion of gastric acid
- M2; increased heart rate
- M3; relaxation of smooth muscle
what would a noradrenergic agonist cause to sympathetic effectors? (4)
- α1; vasconstriction and contraction of smooth muscle
- α2; vasoconstriction
- β1; cardiac stimulation/gut relaxation
- β2; vasodilation and bronchodilation
what would a noradrenergic antagonist cause to sympathetic effectors? (4)
- α1; vasodilation and smooth muscle relaxation
- α2; vasodilation
- β1; gut stimulation
- β2; vasoconstriction and bronchoconstriction
What is the neurotransmitter used in the sympathetic nervous system pre and post ganglionic neurons?
Preganglionic- acetylycholine.
Postganglionic- Noradrenaline.
