DGN - Autonomic Nervous System I Flashcards
What is the anatomical definition of the Autonomic Nervous system?
All those neural pathways that leave the brain and do not innervate the voluntary muscles
What are some roles of the autonomic nervous system? (4)
- Pupillary dilation
- Dilation and constriction of blood vessels
- Force and rate of heartbeat
- Secretions from glands
What is a ganglion?
A group of nerve cell bodies that lie outside the CNS
Preganglionic neurone vs Postganglionic neurone?
Preganglionic neurone
(In CNS)
Postganglionic neurone
(Outside CNS)
What is the difference in efferent neurones in both sympathetic and parasympathetic pathways?
Sympathetic:
- Short preganglionic
- Long postganglionic
Parasympathetic:
- Long preganglionic
- Short postganglionic
How do drugs influence the ANS?
2 types of drug:
- Receptor agonists (mimic neurotransmitters)
- Receptor antagonists (block neurotransmitters)
Where is the preganglionic neurone located for the SNS and the PSNS?
Sympathetic:
Midbrain, medulla or lateral horn
Parasympathetic:
Medulla or Sacral segment
What are some exceptions of the SNS?
Kidneys:
- Postganglionic neurons release dopamine to the smooth muscle instead of norepinephrine
Adrenal gland:
- Preganglionic neurons synapse directly on the adrenal gland, release acetylcholine, and activate nicotinic receptors on the adrenal gland
What is the transmitter involved in excitatory transmission at all autonomic ganglia, both sympathetic and parasympathetic?
Acetylcholine on nicotinic acetylcholine receptors
What neurotransmitter is typically involved in transmission at the postganglionic sympathetic synapse?
Noradrenaline acting on adrenoceptors
What neurotransmitter is usually involved in transmission at the postganglionic parasympathetic synapse?
Acetylcholine acting on Muscarinic receptors
What is the primary function of the enteric nervous system (ENS)?
The ENS consists of neurons that regulate the gastrointestinal tract
What is orthostatic hypotension, and what are its symptoms?
Orthostatic hypotension is a condition characterized by dizziness and fainting upon standing up
What did the Finkelman preparation reveal about the sympathetic nervous system?
The Finkelman preparation provided evidence that the sympathetic nervous system releases an adrenaline-like compound
Where is noradrenaline not the main transmitter at the post ganglionic sympathetic synapse? (2)
1) In sweat glands (Ach)
2) Resistance blood vessels in skeletal muscle
