Autonomic Nervous System Flashcards
What does the autonomic nervous system do?
The ANS controls all vegetative (involuntary) functions
Give examples of what is controlled by the ANS?
heart rate - blood pressure - GI motility - iris diameter
What are the two divisions of ANS?
- The sympathetic division
2. The parasympathetic division
What does the sympathetic nervous system respond to and what changes does it bring?
The sympathetic nervous system responds to stressful situations • “fight or flight” response • heart rate increases • force of contraction increases • blood pressure increases
What does the parasympathetic nervous system control?
The parasympathetic nervous system regulates basal
activities (e.g. basal heart rate) - “rest and digest”
Is the ANS efferent or afferent?
It is entirely efferent (but is regulated by afferent inputs)
What are the Anatomical divisions of brain stem and spinal cord?
M = medullary C = cranial T = thoracic L = lumbar S = sacral
Which regions of the spinal cord, does the sympathetic system emerge from?
In the central regions:
Thoracic and lumbar
Which regions of the CNS, does the parasympathetic system emerge from?
The medullary and sacral regions (from the brain stem and lower part of spinal cord)
In both the parasympathetic and sympathetic system, where is the pre-ganglion is cell body found?
In the CNS
In both the parasympathetic and sympathetic system, where is the post-ganglion is cell body found?
In the PNS
In both the sympathetic and parasympathetic system, which neurone is myelinated and which is unmyelinated?
The pre-ganglionic neurone is myelinated and postganglionic neurone is unmyelinated
In the sympathetic system, which neurone is longer?
The post-ganglionic neurone
In the parasympathetic system, which neurone is longer?
The pre-ganglionic neurone
Where do parasympathetic nerves originate from?
Originate in the lateral horn of the medulla [and sacral spinal cord]
Where do sympathetic nerves originate from?
Originate in the lateral horn of the lumbar and thoracic spinal cord
In the parasympathetic nerves, where are the ganglia located?
Ganglia are located within the innervated tissues
In the sympathetic nerves, where are the ganglia located?
Ganglia are located in the paravertebral (sympathetic)chain close to the spinal cord
Which are the principal neurotransmitters in the ANS?
- acetylcholine (ACh)
* noradrenaline (NA) (US name: norepinephrine)
Which neurotransmitter do parasympathetic and sympathetic pre-ganglionic neurones release at the ganglia?
ACh
What does the pre-ganglionic release of ACH result in?
the activation of post-ganglionic nicotinic ACh receptors which results in influx of Na+ ions that causes depolarisation and carries the impulse forward
What type of receptors are Nicotinic ACh receptors?
ligand-gated ion channels
True or false, All pre-ganglionic neurons are cholinergic?
True
What type of neurones are Parasympathetic post-ganglionic neurons ?
Cholinergic
Which receptors do ACh released by Parasympathetic post-ganglionic neurons act on in the target tissue?
muscarinic ACh (mACh) receptors
What type of receptors are muscarinic ACh (mACh) receptors?
mACh receptors are G-protein coupled receptors (GPCRs).
How many types of mACh receptor subtypes are there?
There are five mACh receptor subtypes (M 1,M2,M3,M4,M5).
What type of neurones are most sympathetic post-ganglionic neurons?
Noradrenergic
Which is the principal neurotransmitter released by Most sympathetic post-ganglionic neurons ?
noradrenaline (NA)
What are the subdivisions of the α-adrenoceptors and β-adrenoceptors?
subdivided into α1 and α2 and β1,β2 and β3 subtypes
Which receptors do noradrenaline (NA) interact with?
α-adrenoceptors and β-adrenoceptors
Some specialized sympathetic post-ganglionic neurons are
cholinergic, not noradrenergic. Which are they?
those innervating sweat glands, hair follicles (piloerection)