Autonomic Nervous System Flashcards
What is the autonomic nervous system?
Maintains homeostasis of internal and external environment. Through involuntary control of the viscera and glands.
What is the autonomic nervous system split into?
Sympathetic and parasympathetic nervous systems.
What do the sympathetic and parasympathetic nervous systems prepare you for?
Fight or flight AND rest and digest respectively.
What does the parasympathetic nervous system do to the body?
PSBHPBB - Pervy sheep bhahh. Herders praise (the) bhahh bhahh. REALLY IMPORTANT! Constricts pupils Stimulates flow of saliva Constricts bronchi Slows heartbeat Stimulates peristalsis (involuntary constriction and relaxation) and secretion in the stomach Stimulates bile release in the liver and gall bladder Contracts bladder. Stimulates an erection. PSBHPBB - Pervy sheep bhahh. Herders praise (the) bhahh bhahh everytime.
What does the sympathetic nervous system do to the body? Identify the differences? (x5)
PSBHPGABOSCP – Pervy sheep bhahh. Herders praise (the) gleeful ahhh bhahhh. Oliver, speak courteously, please! REALLY IMPORTANT! Dilates pupils inhibits salivation Relaxes bronchi Accelerates heartbeat Inhibits peristalsis and secretion Stimulates GLUCOSE PRODUCTION and release in the liver so that you CAN fight or flight without exhausting straight away. Secretion of ADRENALINE and NORADRENALINE by the kidneys Inhibits bladder contraction STIMULATES ORGASM/EJACTULATION. STIMULATES SWEATING CONSTRICTS BLOOD VESSELS (e.g. in the skin). ERECTOR PILLI MUSCLES in the skin. PSBHPGABOSCP – Pervy sheep bhahh. Herders praise (the) gleeful ahhh bhahhh. Oliver, speak courteously, please!
What anatomical regions of the central nervous system concern the sympathetic nervous system? Two names?
Between T1 and L2/3 = called the sympathetic chain. The overall area of emergence is known as thoracolumbar flow.
What anatomical regions of the central nervous system concern the parasympathetic nervous system?
The cranial nerves and the sacral splanchnic nerves (S2-4). No spinal cord!
What are the cranial nerves involved in the parasympathetic nervous system? (x4)
III Oculomotor VII Facial nerve IX Glossopharyngeal X Vagus
What are each of the cranial nerves involved in the parasympathetic nervous system responsible for? (x4) Nature of the vagus nerve?
III Oculomotor – pupil constriction. VII Facial nerve – salivation. IX Glossopharyngeal – salivation (yes, again). X Vagus – bradycardia, gastric motility, digestion, bile release. The vagus nerve is the biggest component of the PNS – this can also be denoted by the picture.
What are ganglia?
Structures outside the CNS containing a collection of neural cell bodies (somas).
What is the structure of the sympathetic nervous system? (in relation to synapses)
Pre-sympathetic neurones run down the length of the spinal cord and terminate (and SYNAPSE) at the area of the spinal cord where the relevant pre-ganglionic efferents are located. Preganglionic sympathetic neurones emerge efferently from the relevant region of the spinal cord. A synapse occurs at the paravertebral ganglia, or some synapse at smaller regions called prevertebral (also called collateral) ganglia. From these ganglia, impulses are synapsed onto new neurones: postganglionic sympathetic efferents – to the target organ. THERE ARE GANGLIA ON EACH SIDE OF THE SPINAL COLUMN. (so there are two ganglia).
What are paravertebral ganglia?
Ganglia that extend the length of the sympathetic trunks.
What are prevertebral ganglia? eg. Coeliac ganglion or Superior Mesenteric Ganglion
Also called collateral ganglia. Ganglia found between the paravertebral ganglia and target organ. Pre-ganglionic neurones still pass through the paravertebral ganglia; they don’t synapse there. They only synapse at the prevertebral (collateral) ganglia.
What neurotransmitters are found along each region of the SYMPATHETIC nervous system? i) Pre-sympathetic –> preganglionic. ii) Preganglionic –> postganglionic. iii) Post-ganglionic –> target organ (x3). Exception?
i) Glutamate always.
ii) Acetylcholine always. EXCEPT in the sympathetic pathway that controls the adrenals – there are NO GANGLIA for neurotransmission (as shown in the photo).
iii) Heart, kidney, blood vessels: Noradrenaline. Sweat glands: Acetylcholine. Renal vessels: Dopaine.
Exception: neurone goes from the CNS and stimulates the adrenal glands to produce adrenaline (80%) and noradrenaline (20%), which THEN go on to affect the target organs e.g. heart and blood vessels. Here, the neurotransmitter acetylcholine stimulates the adrenal glands.
NOTE: drugs that block the SNS pathways may not affect adrenaline or noradrenaline, because it is secreted into the circulation, and not associated with pre-ganglionic and post-ganglionic synapses!
What are noradrenaline and adrenaline also called?
Norepinephrine and epinephrine, respectively.
What is the structure of the parasympathetic nervous system? (in relation to synapses)
Cranial (or sacral) nerves emerge from the CNS. They are inside (or LIE VERY CLOSELY) to the target organ. As a result, the pre-ganglionic neurone is very long, while the post-ganglionic neurone is extremely small (and inside the target organ only (if the ganglia are inside the target organ)).
What neurotransmitters are found along each region of the PARASYMPATHETIC nervous system?
The cranial nerves emerge straight from the brain, so there’s no synapse in the spinal cord. The first synapse is in the ganglia close to or inside the target organ – between the long parasympathetic preganglionic neurone and the parasympathetic postganglionic neurone. Acetylcholine is released into this synapse. Acetylcholine is also released into the synapse between the postganglionic neurone and the effector organ e.g. heart. View the top of the picture. (presumably, there is some kind of pre-parasympathetic neurone that extend down to S1-4 for the sacral parasympathetic nerves!)
For comparison, how is the somatic nervous system structured in relation to its synapses?
There is a long neurone that extends down to the relevant section of the spinal cord. Synapse occurs where this neurone terminates – using Glutamate. Motor neurone goes straight to effector = skeletal muscle! Here, the neuromuscular junction uses ACETYLCHOLINE – this is important later when we look at drugs affecting the nervous system!
Why does the anatomy of the sympathetic and parasympathetic nervous differ?
Sympathetic NS wants to cause a mass response so that the whole body is mobilised, ready for increased activity. Fight/flight is a whole-body response. Parasympathetic NS is discrete or localised, as it looks to conserve body energy – this requires cutting down on specific areas that are not needed.
What are the principle stages of biosynthesis for noradrenaline (and the sites of biosynthesis (x2))?
Note that dopamine is synthesised in the pathway. Noradrenaline is synthesised in the PRESYNAPTIC vesicles from dopamine.
What are the principle stages of biosynthesis and metabolism of acetylcholine? And the enzymes? (x2)
Choline acetyltransferase catalyses the forward reaction (in the glial cells and pre-synaptic neurones). Acetylcholinesterase catalyses the backwards reaction (in the synaptic cleft).
Why is acetylcholinesterase a clinically important enzyme to target in pharmacology?
Acetylcholinesterase can be targeted in pharmacology to increase stimulation of the post-synaptic neurone.
What is the name of the structure labelled? (could be x2 things that differ SLIGHTLY)
INTERMEDIOATERAL CELL COLUMN – where the sympathetic preganglionic neurons emanate from. LATERAL HORN OF THE SPINAL CORD – contains cell bodies of preganglionic neurons, found not just in T1 – L2-3 (as is the intermediolateral cell column), but also found in the PNS for S2-S4.
What is the structure of the paravertebral ganglia at each ‘swelling’?
The white ramus communicans carries preganglionic axons of the sympathetic nervous system into the paravertebral ganglia. The grey ramus communicans takes postganglionic neurons away from the ganglia, towards the target organs. Preganglionic neurones that do NOT terminate here, leave the ganglia in a different direction and are carried separately to the prevertebral (collateral) ganglia via splanchnic nerves. You need to recognise what they look like anatomically, relative to each other.