Autonomic Nervous System Flashcards
Which part of the autonomic NS is most active during exercise or stress?
Sympathetic
When the NS is functionally classified, which system is voluntary and which system is involuntary?
Voluntary = Somatic (external)
Involuntary = Autonomic (internal) Sympathetic/Parasympathetic
Which part of the autonomic NS is the ‘fight or flight’ response?
Sympathetic
Tachycardia, increased BP, increased blood flow to muscle, inhibited GI peristalsis, bronchial dilation and pupil dilation are responses to what?
The sympathetic NS/fight or flight
Allow more blood and oxygen to get to tissues, better vision, no poo so can run away
In the sympathetic NS, where would you find the pre-ganglionic neurone?
In the spinal cord
What type of NT does the pre-ganglionic neurone release in the sympathetic NS?
Acetylcholine (ACh)
In the sympathetic NS, after the pre-ganglionic membrane has released ACh, what type of receptors does it bind to?
Where are these receptors?
The ACh binds to Nicotinic Acetylcholine Receptors
These are in the post-ganglionic neurone
In the sympathetic NS, the pre-ganglionic membrane in the spinal cord releases ACh. This is picked up in the post-ganglionic membrane at the nicotinic receptors. The ganglion is a collection of nerve cell bodies.
What does the post-ganglionic membrane then release?
Noradrenaline (Nor)
In the sympathetic NS, once the post-ganglionic membrane has released Nor, where does it go an what receptors pick it up?
Adrenergic Receptors pick up Nor in the Target tissue (e.g. heart or blood vessels). The receptors then get the target tissue to dilate/contract/inhibit etc
What does nicotine in cigarettes stimulate?
ACh receptors (this is why we call them nicotinic) This means it stimulates the sympathetic NS
What do nicotinic receptors control?
Ion channels (ACh in the ligand) These nicotinic receptors are found in the CNS, ANS ganglia and the neuromuscular junction
Where can nicotinic receptors be found?
CNS, ANS ganglia and the neuromuscular junction (the synpase from nerves that supply muscle)
What type of ganglia in the sympathetic NS go to the vessels of the skin, skeletal muscle, pilomotor muscle, sweat glands, smooth muscle of the eye, salivary glands, bronchi, heart, pulmonary vessels and adrenal gland?
Paravertebral Ganglia
What type of ganglia in the sympathetic NS go to the gut, renal/hepatic vessels, bladder and genitalia?
Prevertebral Ganglia
pre = toilety stuff
What NS is the adrenal medulla/gland associated with?
Sympathetic
After acetylcholine has been picked up by the nicotinic receptors in the adrenal medulla, what does it secrete?
Adrenaline and Noradrenaline
The adrenal medulla releases adrenaline and noradrenaline in what ratio?
4:1
so 4 adrenaline to 1 noradrenaline
The adrenal medulla is derived from neuronal tissue. The hormones it releases act on what?
Sympathetic effector cells
Cocaine and Amphetamine are thought to act via the Sympathetic NS. What are they thought to prolong to have their stimulating effects?
Neurotransmitters - primarily Noradrenaline, but also serotonin and dopamine
Bradycardia, increased GI motility, bronchial constriction, pupil constriction and gastric acid secretion are thought to be responses of what NS?
Parasympathetic NS - ‘rest and digest’
In the parasympathetic NS, the pre-ganglionic neurone releases ACh. This is picked up by the nicotinic receptors in the post-ganglionic neurone. What does the post-ganglionic neurone then release?
ACh
In the parasympathetic NS, once the POST-ganglionic neurone has released ACh, what receptors pick it up and where?
Muscarinic ACh receptors in the target tissue
What are the 2 classes of ACh receptor?
Nicotinic and Muscarinic
Which type of ACh receptor is found at parasympathetic NEUROEFFECTER junctions?
Muscarinic
Which type of ACh receptor is found at ganglionic synapses of both sympathetic and parasympathetic divisions?
Nicotinic
What antagonist can block muscarinic ACh receptors?
Atropine/belladonna (this would allow a pupil to dilate)
What antagonist can block nicotinic ACh receptors?
Curare - a muscle relaxant
The cranial nerves 3, 7, 9 and 10 and the sacral nerves 2 and 4 supply what?
What is this called?
The parasympathetic NS = cranio-sacral outflow
cranial = top stuff sacral = toilety stuff (pelvic ganglia)
The eye, vasculature, heart and respiratory tract are examples of what in the parasympathetic NS?
Autonomic Effector Tissues
In the sympathetic NS, what type of NT is released?
Noradrenaline and Adrenaline
In the sympathetic NS and the parasympathetic NS, which has the short and which has a long preganglionic neurone?
Sympathetic - short
Parasympathetic - long
(think of as sympathetic needing to be quick and short, whilst para is resting and long)
In the sympathetic and parasympathetic NS, where are the ganglia located in each?
Sympathetic - ganglia are paravertabral
Parasympathetic - ganglia are close to the effector (snuggly and relaxed)
In the sympathetic and parasympathetic NS, which has catabolic and which has anabolic metabolic/physiological effect?
Sympathetic - catabolic (fight/flight)
Parasympathetic - anabolic (rest/digest)
In autonomic control, the sympathetic and parasympathetic systems often exert opposite actions to provide dual control.
Why?
Finer control as can modify/regulate both
If was just an accelerator then it wouldn’t be able to slow down quickly - think of accelerator/brake analogy
In the heart, the SNS increases HR and contraction force, and the PNS decreases HR and contraction force.
In the airways, the SNS dilates them and the PNS constricts them.
How about blood vessels?
PNS has no effect here.
In the skin and kidney the SNS vasoconstricts and in the muscles and liver it vasodilates
What are the divisions in the ANS?
Sympathetic and Parasympathetic
In which NS do you get thoraco-lumbar outflow?
SNS
In which NS do you get cranio-sacral outflow?
PNS
Do the SNS and PNS both have pre-ganglionic and post-ganglionic neurones?
Yes
What are the main NTs in the ANS?
ACh and Nor
What NT is released by the pre-ganglionic neurones of both the SNS and PNS?
ACh
What NT is released by post-ganglionic neurones in the SNS?
Nor
What does the adrenal gland mainly secrete?
Adrenaline (4) also some Nor (1)
