1 - Intro to ANS Flashcards
Pharmacodynamics
What drugs do to body
Pharmacokinetics
What body does to drug
What are the three branches of the peripheral nervous system (and what do they control)
Autonomic [automatic], somatic and (neuroendocrine)
exocrine glands, smooth muscle, cardiac muscle, metabolism, host defence
skeletal muscle, respiratory muscle
growth, metabolism, reproduction, development, salt/water balance, host defence
Is vagus sympathetic or parasympathetic
Parasympathetic
Parasympathetic
Rest and digest, thoracic lumbar
Sympathetic
Fight or flight, cranial/sacral
Describe the relative lengths of the pre- and post-ganglionic fibres and neurotransmitter(s) in the parasympathetic nervous system
(Only 1 type) Long pre-ganglionic, short post-
Acetylcholine (ACh)
Discrete, localised 1:1
Describe the relative lengths of the pre- and post-ganglionic fibres and neurotransmitter(s) in the sympathetic nervous system
(1 type w/ exceptions) Short pre-ganglionic, long post-
ACh then NorA (90%)
- Same but no post ganglionic, adrenal medulla secretes A/NorA (80:20)
- Same but ACh for both (e.g. sweat gland)
Coordinated, divergent 1:20 (formation of trunk)
Why does sweat use ACh as post-ganglionic neurotransmitter
ACh is also used by parasympathetic nervous system
Parasympathetic often controls secretions (rest and digest)
Sweat (though sympathetic) is also a secretion
Thus may be a relic
Summarise the layout of the enteric nervous system
Chemo and stretch receptors (mucosal)
Sensory neurones
via Interneurones
Submucosal (Meissner)/Mesenteric (Auerbach) plexus
Motor neurones [ACh or substance P to contract smooth muscle, vasoactive intestinal peptide or nitric oxide to relax smooth muscle)
What does the somatic nervous system use as its neurotransmitter
The only similarity is that the somatic nervous system also uses ACh as its neurotransmitters
Direct
What are the types of cholinoceptor
Nicotinic and Muscarinic
Briefly outline the structure and location of nicotinic receptors
Type 1 - ionotropic
In nervous system, therefore all pre-ganglions
Briefly outline the structure and location of muscarinic receptors
Type 2 - g protein coupled
In effector organ, therefore all post-ganglion where ACh is used
Manipulation of which receptor would allow you to control all aspects of the autonomic nervous system
Nicotinic receptors
Which of the following effects would be observed after blockade of nicotinic receptors in an individual at rest?
- Bronchoconstriction
- Increased sweat
- Constipation
- Increased urine
- Short-sightedness
At rest = parasympathetic function
Therefore observation must equate to opposite of parasympathetic function.
- Constipation
What effect would blockade of nicotinic acetylcholine receptors have on heart rate;
- At rest
- During exercise
- At rest parasympathetic (vagus) keeps HR down so inhibition would cause an increase in HR
- During exercise the sympathetic system is in control and causes an increase in HR so inhibition will decrease the rate of increase
Draw out the diagram of target organs and the effect of either sympathetic or parasympathetic stimulation
See diagram (6,5) *exception, 1 only one function, 2 one pathway for both
Eyes, Salivary Glands *Trachea and Bronchioles, 2*Skin 2Liver, Heart 1Adipose, GI 1Kidneys, 2BVs Ureter and Bladder
Pupil, Ciliary Muscle
Detrusor, trigones, sphincter
Rate and contractility
Tone, contractility and sphincter
How many subtypes of muscarinic receptor are there and where are they found
5 subtypes
M1 Neural {forebrain, learning and memory}
M2 Cardiac {brain, inhibitory autoreceptors}
M3 Exocrine and Smooth Muscle {hypothalamus, food intake}
M4 Periphery; prejunctional nerve endings
M5 Striatal dopamine release
What are the types of adrenoceptor
a1, a2, b1, b2
Where are adrenoceptors located
Only in the sympathetic nervous system
In the effector organs where NorA or A are the neurotransmitters
Where are the cholinoceptors located
Both in the parasympathetic and sympathetic nervous systems
Nicotinic is in all between pre and post
Muscarinic only in effector organs where ACh is used
Draw diagram which shows location of all the receptors
See diagram
What are 3 important questions to consider for all drugs
- What is the drug target? (nicotinic/muscarinic, adrenoceptor)
- Where is the drug target? (side effects due to different targets)
- What is the end result [of the interaction]?
