Introduction to the ANS Flashcards
Pharmacodynamics
What drugs do to the body
Pharmacokinetics
What the Body does to the drugs
Pupil when you enter a dark room - SNS or PNS?
SNS
Digestion - SNS or PNS?
PNS
Blood loss effect on Heart - SNS or PNS?
SNS
Divisions of the Nervous system,
CNS and PNS (divided into ANS and other)
How many segments is the spinal cord divided into?
31 (8C, 12T, 5L, 5S, 1C)
What is a ganglion?
A ganglion is a group of cell bodies outside the CNS
Outflow in the SNS?
Thoracolumbar (T1-L2 or L3)
Outflow in the PNS?
Craniosacral (CN III, VII, IX, X)
What are the main target organs of the PNS?
Gastrointestinal - Digestion is promoted, increased secretions, increased motility and tone
Heart - decreased rate and contractility
Ureters and Bladder - Contraction of detrusor; relaxation of trigone and sphincter
Trachea and Bronchioles - constriction
Salivary Glands - Copious, watery secretion
Eye - constriction of Pupil, contraction of the ciliary muscle
What are the main organs of the SNS?
Heart - increase rate and contractility
Eye - Dilation of Pupil
Trachea and Bronchioles - Dilation through Adrenalin?
Adipose Tissue - Lipolysis
Liver - Gluconeogenesis, Glycogenolysis
Kidney - Increased Renin secretion
Ureters and Bladder - Relaxes detrusor; constriction of trigone and sphincter
Blood vessles - constriction (skin, mucous membranes and splanchnic area )
Blood vessles - Dilation of BV in skeletal muscle
Skin - Piloerection, Increased sweating (C)
Salivary Glands - Thick, viscious secretion
What is the main NT in the SNS?
NE
What is the main NT of the PNS?
ACh
In what ways do cranial and spinal nerves differ from one another?
Cranial nerves emerge from the brain, some are sensory some are motor, some are mixed.
Spinal nerves from the spinal cord, all are mixed.
What are 2 exceptions to the normal structure of the SNS?
- Sweat glands: postganglionic neurone has ACh as the NT (secretions are usually linked to PNS, however sweating is SNS mediated)
- The adrenal medulla only has 1 nerve fibre, it acts like preganglionic and releases ACh, when stimulated the Adrenal medulla releases A (4) and NA (1)
What are the 2 components of the enteric NS?
submucosal and myenteric Plexus
How is the enteric nervous system controlled?
via autonomic control (SNS and PNS) as well as under local control of the environment on the gut.
NT in all preganglionic fibres
ACh
Where can muscarinic ACh receptors be found?
At effector organs where ACh is the NT.
Where can nicotinic ACh receptors be found?
In the ganglia between pre and postsynaptic neurones.
-> throughout the entire ANS
What are the subtypes of muscarinic cholinoreceptors?
M1 – Neural (Forebrain – learning & memory)
M2 – Cardiac (Brain – inhibitory autoreceptors)
M3 – Exocrine & smooth muscle (Hypothalamus – food intake)
M4 – Periphery: prejunctional nerve endings (inhibitory)
M5 – Striatal dopamine release
Adrenoreceptors - receptor type
G coupled protein receptor
Nicotinic receptors - receptor type
Ion channel receptors, stimulated by ACh and nicotine
Muscarinic receptors - receptor type
GCPR, stimulated by ACh and muscarine
3 things that should be considered for all drugs
- What is the drug target?
- Where is the drug target?
- What is the end result of the interaction?
How does the enteric NS work?
Sensory neurone connected to mucosal chemoreceptors and stretch receptors detect chemical substances in the gut lumen or tension in the gut wall caused by food.
Information relayed to submucosal and myenteric plexus via interneurons.
Motor neurones release acetylcholine or substance P to contract smooth muscle or vasoactive intestinal peptide or nitric oxide to relax smooth muscle.
Draw the synthesis and degradation of ACh at the synapse.
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Draw the synthesis and degradation of Noradrenaline at the synapse.
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