Autonomic Physiology Flashcards
What does autonomic nervous system mean? what muscle type does it act on.
Means it controls the things you don’t think about
Smooth and cardiac
What does the somatic nervous system do? What muscle type does it act on
Controls the voluntary stuff, is sensory. Controls skeletal muscle
Autonomic vs Somatic;
Describe how specialized each it, the type of receptor used and if if they excite/inhibit the target
Somatic - is s a specialized NMJ, has ionotropic receptors and always excites target
Autonomic - Less specialized, used metabotropic receptors and may excite or inhibit
Talking now only about autonomic - what does the sympathetic system do?
Fight or flight - has coordinated effects
What does the parasympathetic system do?
Rest and digest - has independent effects
What spinal cord region does the sympathetic nervous system flow from?
Thoracic and Lumbar
In sympathetic - is the pre-ganglionic fibres longer or shorter than the post-ganglionic fibres?
Shorter - ganglia lies close to spinal cord
In the sympathetic - what acts on what receptor at the ganglia
Preganglonic fibres release acetylcholine (Ach) which act on nicotinic receptors
In sympathetic - what do post-ganglionic fibres release and what receptor does it act on?
Noradrenaline - acts on alpha or beta receptors
In parasympathetic - what spinal cord region do the fibres exit from?
Cranial and Sacral
In parasympathetic - are the pre-ganglionic fibres longer or shorter than post?
Longer - ganglia lies closer to target
In parasympathetic - what acts on what receptor at the ganglia?
Ach acts on nicotinic receptors
In parasympathetic - what do post-ganglionic fibres release and on what receptor?
Ach again on muscarinic receptors
Do postganglonic fibres always follow the rules?
No - some sympathetic fibres innervate sweat glands and some release non-adrenergic non-cholinergic transmitters
Of the two (paraS or S) which has the hormonal component?
Sympathetic
How does all these fibres and stuff cause all these different effects?
Depends on what is released and what receptor it acts on
The eye - Sympathetic system - How does it make the eye dilate?
Activates Beta 2 receptor causing ciliary muscle to relax and eye focuses far away
Activates alpha 1 receptor, radial muscle on iris contracts and makes pupils larger
The eye - parasympathetic system - How does it make the eye constrict?
Activates muscarinic receptors causing ciliary muscle to contracts & eye focuses close up
Activates muscarinic receptors causing sphincter muscle to contract & makes pupil smaller
The heart - Sympathetic system - How does it make the heart beat faster?
Activates beta 1 receptors on pacemaker cells and myocytes causing increase in heart rate and strength of contraction
The heart - parasympathetic system - How does it make the heart beat slower?
Activates muscarinic receptors on pacemaker cells decreasing heart rate
Has little effect on myocytes therefore little effect on strength of contraction
The lungs - Sympathetic system - How does it make the lungs dilate?
Activates beta 2 receptors on smooth muscle of airways causing them to relax and dilate
The lungs - parasympathetic system - How does it make the airways constrict
Activates muscarinic receptors making smooth muscle constrict
Blood vessels - Sympathetic system - How does it make blood flow decrease?
Acts on alpha 1 receptors causing smooth muscle to contract and blood flow in that region decreases
Blood vessels - Sympathetic system - How does it make blood flow INCREASE
Acts on beta 2 receptors causing smooth muscle to relax and blood flow in that region increases
Why in blood flow - is it just the sympathetic system used?
Cause during fight or flight, bp needs to increase BUT blood is sent to where its needed and is taken from where its not…
The gut - sympathetic - how does it decrease gut motility?
Activates alpha/beta receptors on the smooth muscle of the gut decreasing motility
Acts on alpha receptors in pancreas inhibiting secretion of enzymes
The gut - parasympathetic - how does it increase gut motility?
Activates muscarinic receptors on smooth muscle of gut which increases motility
Acts on muscarinic receptors in pancreas increasing secretion of enzymes
Salivary glands - Symp - how does it dry mouth?
Activates beta receptors stimulating thick secretion rich in enzymes
Salivary glands - ParaSymp - how does it make mouth drool
Acts on muscarinic receptors which stimulates a profuse of water solution
Basically - tissues have dual innervation and effects can be complementary or antagonistic
True - I give up with these examples
