Autonomic Physiology Flashcards
What does the autonomic nervous system control?
The things we don’t think about
Smooth muscle
Organs
What do afferent neurones carry?
Sensory info - going in
What do efferent neurones carry?
Motor info - coming out
What does the somatic nervous system control?
Voluntary movement
Skeletal muscle
What is the term used for the sympathetic NS?
Fight or flight
What is the term used for the parasympathetic NS?
Rest and digest
What is a group of cell bodies known as?
Ganglion
Does the autonomic nervous system ever control skeletal muscle?
No, never
Does the somatic NS always excite its target?
Yes
Does the autonomic NS always excite its target?
No
May excite or inhibit
What regions of the body do parasympathetic nerves flow to?
Cranio-sacral
What regions of the body do the sympathetic nerves flow to?
Thoraco-lumbar
Compare the lengths of the pre and post ganglionic fibres in the parasympathetic NS
Long preganglionic fibres
Short postganglionic fibres
Compare the lengths of the pre and post ganglionic fibres in the sympathetic NS
Short preganglionic fibres
Long postganglionic fibres
From where on the spinal cord do the sympathetic nerves exit?
From T1-L2
In the sympathetic nervous system what is the white ramus?
The preganglionic fibre
In the sympathetic NS was is the grey ramus?
The postganglionic fibres
What receptors does acetylcholine work on?
Cholinergic receptors
What receptors does noradrenaline work on?
Adrenergic receptors
In the sympathetic NS what does the preganglionic fibres release?
Acetylcholine
In the sympathetic NS what does the postganglionic fibres release?
Noradrenaline
Where do the postganglionic cells of the adrenal medulla release adrenaline and noradrenaline and why?
Into the blood
Because they have no axons
Where do the parasympathetic nerves exit from the spinal cord?
Some of the cranial nerves
Sacral S2-S4
Where does the ganglia lie in the parasympathetic NS?
Close to or within the target
In the parasympathetic NS what do the preganglionic fibres release?
Acetylcholine
In the parasympathetic NS what do the postganglionic fibres release?
Acetylcholine
What receptors are on the targets in the parasympathetic NS?
Muscarinic
There are a group of sympathetic nerves that do not release noradrenaline at the target but what do they release instead?
Acetylcholine again
What receptors do acetylcholine work on?
Nicotinic receptors
Muscarinic receptors
What receptors does noradrenaline/adrenaline work on?
alpha receptors
Beta receptors
What is antagonist action?
When the opposite effects are exerted on the same thing
What receptors does the sympathetic system activate on pacemaker cells?
B1
What effect does the sympathetic system have on the heart?
Increases heart rate
Increases the strength of contraction
What effect does the sympathetic system have on the ciliary muscle?
Activates B2 receptors
Relaxes eye focusing far away
What effect does the sympathetic system have on the radial muscle?
A1 receptors activated
Muscle relaxes
Makes pupils larger
What effect does the para system have on the ciliary muscle?
Activates muscarinic receptors
Contracts ciliary muscle
Eye focuses close up
What effect does the para system have on the the sphincter muscle?
Activate muscarinic receptors
Contracts sphincter muscle
Makes pupils smaller
What effect does the sympathetic system have on the heart?
Activates B1 receptors On pacemaker cells Increases heart rate On myocytes Increases strength of contraction
What effect does the para system have on the heart?
Activates muscarinic receptors
Acts on pacemaker cells
Decreases heart rate
What effect does the sympathetic system have on the lungs?
Activates B2 receptors
On airway muscle
Makes muscle relax and dilates airways
What effect does the para system have on the lungs?
Activates muscarinic receptors
Makes smooth muscle contract
Constricts airways
What effect does the sympathetic system have on the blood vessels?
Activates a1 receptors
On smooth muscle of vessels contracting them Blood flow decreases
Activates B2 receptors on smooth muscle of vessels
Blood flow increases
What effect does the parasympathetic system have on blood vessels?
Usually no effect
What is tone in blood vessels?
Can turn up or turn down the tone to contract and relax
What effect does the sympathetic system have on the gut?
Activates receptors on smooth muscle of gut
Decreasing gut motility
Activates a receptors in pancreas inhibiting the secretion of enzymes
What effect does the para system have on the gut?
Activates muscarinic receptors on smooth muscle of gut
Increasing gut motility
Increasing pancreatic secretion
What effect does the sympathetic system have on salivary glands?
Activates B receptors
Thick secretion rich in enzymes
What effect does the para system have on salivary glands?
Activates muscarinic receptors
Thin waters secretions
What effect does the sym system have on the bladder?
Activates B2 receptors relaxing the muscle of the bladder wall
Stops urination
What effect does the para system have on the bladder?
Activates muscarinic receptors
Contracting smooth muscle on bladder wall
Relaxing smooth muscle on spinchter causing urination
What effect does the sym system have on the reproductive tract?
Activates a1 receptors on smooth muscle of urethra
Contracting smooth muscle causing ejaculation
What effect does the para system have on the reproductive tract?
Activates muscarinic receptors on smooth muscle of corpus cavernosum
Relaxes the muscle causing erection
What is an antagonist effect?
Two things that exert the opposite effect on the same organ
