The Autonomic Nervous System Flashcards
what is the autonomic nervous system
this is the visceral effect component of the peripheral nervous system.
what are the involuntary activities that the autonomic nervous system controls
smooth muscle
cardiac muscle
various glands
what are the two divisions of the autonomic nervous system
sympathetic and parasympathetic
where are the cell bodies of preganglionic neurons found in the brainstem
the 3,7,9 and 10 cranial nerves.
where are the cell bodies of preganglionic neurons found in the sacral spinal cord
S2, 3, 4
what do the brainstem preganglionic neurons control
head structures for 3,7 and 9 cranial nerve
thoracic and abdominal organs for cranial nerve 10
what do the sacral preganglionic region neurons control
pelvic organs
where are cell bodies of pre ganglionic neurons found ni the thoracic and lumbar regions of the spinal cord
T1-L2
what is the organisation of ganglionic neurons for the parasympathetic nervous system
they have long preganglionic neurons and short post glanglionic neurons
the ganglions are near or actually in the effector organ, which is why they are so long
what is the organisation of ganglionic neurons in the sympathetic nervous system
the pre and post ganglionic neurons are similar in length, and they have a synapse in the sympathetic chain or one of the pre-vertebral ganglia in the adrenal medulla
what effect does the parasympathetic nervous system have
generally has discrete actions on single organs in the body core like the salivary glands and the heart
also has conservative anabolic effects - so it stores energy for digestion and has a slowing heart
where do the preganglionic neurons that go out through the CN3 control
iris and ciliary muscles
where do the preganglionic neurons that go out through the CN7
lacrimal and salivary glands
where do the preganglionic neurons that go out through the CN9
lacrimal and salivary glands
where do the preganglionic neurons that go out through the CN10 (vagus)
the heart, bronchi and gastrointestinal tract
where do the preganglionic neurons that go out through the sacral 2-4 region
bladder and genitalia
how does the sympathetic nervous system affect the body
has more widespread actions affecting the whole body due to the distribution of sympathetic nerves.
controls homeostasis through blood pressure for thermoregulation
also is part of the fight, flight or fright by meeting demands of active muscle and anxiety
where are sympathetic neurons found
the thoraco lumbar region - affecting the iris, blood vessels, heart, bronchi, gi tract, adrenal medulla, and bladder and gentilia
what are the smooth muscles affected by the autonomic nervous system
blood vessels in various parts of the body, as well as bronchi and bronchioles
how is the heart impacted by the autonomic nervous system
the progress of the gastro intestinal tract can impact rate and force of contraction
which glands are impacted by the autonomic nervous system
salivary glands
gastro intestinal glands
sweat glands
what is metabolism affected by
the autonomic nervous system
does the autonomic nervous system control breathing
no, the breathing muscles are skeletal muscles and are controlled by somatic nerves
what action does the parasympathetic nervous system create in the iris
contraction
what action does the parasympathetic nervous system create in the ciliary muscle
contraction
what action does the parasympathetic nervous system create in the salivary glands
secretion, which is copious and watery
what action does the parasympathetic nervous system create in the lacrimal gland
secretion
what action does the parasympathetic nervous system create in the nasal glands
secretion
what action does the parasympathetic nervous system create in the blood vessels
no action
what action does the sympathetic nervous system create in the iris
contraction
what action does the sympathetic nervous system create in the ciliary muscle
relaxation
what action does the sympathetic nervous system create in the salivary glands
low volume secretion of viscous saliva
what action does the sympathetic nervous system create in the lacrimal glands
secretion
what action does the sympathetic nervous system create in the nasal glands
no action
what action does the sympathetic nervous system create in the blood vessels
constriction and dilation
what are the transmitters of the autonomic nervous system
acetyl choline and noadrenaline.
give a summary of the autonomic nervous system adrenergic receptors
variations in the effects of transmitters led to identification of different types of receptor.
noradrenaline causes contraction of smooth muscle in blood vessles (the alpha receptor) and relaxation of bronchial smooth muscle (the beta receptor)
why is adrenaline used in local anaesthetics
creates a more rapid response and prevents the local going to the rest of the body because it is not being injected into the bloodstream
how can the different types of cholinergic receptors be distinguished by drugs
post ganglionic neurons and neuro effector junctions on muscarinic receptors can be blocked by atropine
pre ganglionic neurons and post ganglionic neuron synapses on nictotinic receptors found on the neuromuscular junctions
what is the comparison between sympathetic and parasympathetic nervous system
they usually have opposing effects apart from in genitalia. the control is achieved by balancing their activity.
what nerves are blood vessels supplied with
sympathetic nerves only. the control of blood vessel diameter is achieved by varying activity in the sympathetic nerves
which part of the autonomic nervous can the adrenal medulla be found
the sympathetic nervous system
how does the activity of the autonomic nervous system affect the heart in relation to the gastrointestinal tract
circulation is diverted toward the GIT when you are relaxing to improve digestion. major changes in volume are associated with the vascular system and the force of contraction of the heart can change
how is the sympathetic nervous system related to breathing
it does not control it, it just facilitates the absorption of oxygen
what is atropine associated with
blocking of muscarinic receptors
what is the peripheral nervous system broken into
the sensory and motor system
what is the motor system branch of the peripheral nervous system broken into
somatic and autonomic control
what is somatic control
voluntary
what is autonomic control
visceral and involuntary - it stands by itself
what are the branches of the autonomic nervous system
sympathetic and parasympathetic
how many motor neurons does the somatic nervous system take to reach the effector neuron
one - the alpha motor neuron that extends all the way from the anterior grey horn of the spinal cord to an effector organ
how many motor neurons does the autonomic nervous system require to reach the effector organ
two - the first is coming out from the spinal cord or brain stem, and this is the preganglionic motor neuron. after it is the post ganglionic motor neuron
where is the sympathetic nervous system found
within the spinal cord in the thoraco lumbar outflow.
give a brief summary of the sympathetic autonomic nervous system
this is part of the body’s fight, flight or fright response in stressful situations.
the thoraco lumbar region is where it is found. within this region is where the preganglionic cell bodies of the sympathetic autonomic nervous system are found, and where the sympathetic nervous system is coming out
in which parts of the nervous system can the parasympathetic nervous system be found
brain stem and sacral region of the spinal cord
where can preganglionic cell bodies be located on the brain stem
- cranial nerve three has parasympathetic output as there are parasympathetic fibres that move with the ocular motor cranial nerve that supplies part of the eye
- superior salivatory nucleus is a location of preganglionic cell bodies and they come out as part of the CN7 facial nerve which again as parasympathetic outflow
- the inferior salivatory nucleus has preganglionic neurons that come out as part of the glossopharyngeal nerve CN9
- vagus goes to many different tissues
what are the two portions of the parasympathetic nervous system
cranial nerves and the sacral region
what are the different forms of autonomic neurons
pre and post ganglionic neurons
how do the lengths of preganglionic motor neurons differ depending on the S or PS nervous system
long in the PS and short in the S
why are the preganglionic motor neurons long in the parasympathetic nervous system
travel very far until they reach very close to the target organ, and may even be in the organ
what are ganglia
a group of cell bodies located within the peripheral nervous system. only one type of ganglia is found in the parasympathetic nervous system. the pre are so long so the terminal can go into the target organ. this is an intramural ganglion
what are the different names that can be give to post ganglionic motor neurons from the parasympathetic nervous system
terminal or intramural depending on if they are at the target organ or are inside the target organ
what chemical is released at the ganglion in the sympathetic nervous system
acetyl choline to stimulate the post ganglionic motor neuron
what are the cholinergic fibres
the preganglionic fibres that release acetylcholine ot the post ganglionic motor neurons in both the S and PS nervous system, and the post ganglionic fibres that release acetylcholine to the effector organ
what are the adrenergic fibres
the post ganglionic fibres of the parasympathetic nervous system that release norepinephrine onto their target tissue
where are the cell bodies of the preganglionic sympathetic motor neurons found
the intermediate lateral grey horn in the thoracal lumbar region
describe the route that preganglionic neurons take in the sympathetic nervous system
- cell bodies foud in the intermediate lateral grey horn
- move out along with somatic fibres through the ventral route, and go into the ventral ramus
- go into chain ganglia through the white rami communicants
- leave through the grey rami communicants
- go as part of a spinal nerve to arrector pili, blood vessels and sweat glands
- some can decide not to go back out through the grey rami communicants and instead go down another level in the spinal cord into another ganglia and synapse there, and go out through the grey rami communicants on the lower level and out to a spinal nerve, or alternatively leave on its own
- others who decide not to go through the grey rami communicants can go down an alternate tunnel to the front of the aorta.
- or they could ascend up the spinal
what are the different routes that the preganglionic cell bodies that can take
they can ascend or descend the spinal cord or they can go out at the same level
what are splanchnic nerves
these are nerves that leave the spinal cord as their own nerve rather than joining onto a spinal nerve
where must splanchnic nerves go
collateral ganglia
what are the different types of ganglia that go through the alternate tunnel rather than going through the grey rami communicants in the chain ganglia
- pre aortic
- pre vertebral
- collateral
- sub diaphragmatic
what do sympathetic neurons affect
the iris, blood vessels, heart, bronchi, gi tract, adrenal medulla, and bladder and gentilia
what are the adrenergic receptors
alpha 1, alpha 2, beta 1, beta 2 and beta 3
describe alpha one adrenergic receptors
these have an effect in all smooth muscles, glands and organs that are relevant to the sympathetic nervous system other than the heart and the kidney. they can constrict blood vessels
describe beta one adrenergic receptors
these have an effect on the heart and juxtaglomerular cells in the nephrons of the kidney. they increase heart rate and contraction, and through the nephrons they are able to increase blood pressure and volume
which adrenergic receptors are stimulatory
alpha one and beta one
describe alpha two receptors
found in presynaptic terminals on the pre ganglionic neurons, and in blood vessels. they relax blood vessels and stop exaggerated effects at the synaptic terminals to provide negative feedback
describe beta two receptors
these have an effect on smooth muscle, glands and organs relevant to the sympathetic nervous system and are involved in their relaxation, such as relaxation of the airways to allow more breathing
which adrenergic receptors are inhibitory
alpha two and beta two
