What is the Autonomic Nervous System (ANS)?
Controls the automatic and involuntary actions of tissues and organs
Name 3 ANS functions
- Gland secretion
- Rate/force of heart contraction
- Contraction/relaxation of smooth muscles (blood vessels, bronchioles, GIT)
What are the 2 subdivisions of the ANS? What are they responsible for?
- Sympathetic Nervous System (SNS) - “fight or flight”
2. Parasympathetic Nervous System (PNS) “rest and digest”
Describe the SN Pathway
- Arises from spinal cord, T1-L2 (thoraco-lumbar)
- Short pre-ganglionic, long post-ganglionic neuron
How does the SN Pathway work?
- The pre-ganglionic neurons are cholinergic -> release ACh
- Most post-ganglionic neurons are adrenergic -> release adrenaline
- Adrenaline stimulates body responses (“fight or flight”
Name 3 body parts the SN pathway effects
- Eyes (dilate)
- Sweat glands (increased sweat secretion)
- Heart (increased heart rate and force of contraction)
Describe the PN pathway
- Arises from S1-S4 (cranio-sacral)
- Long pre-ganglionic neuron, short post-ganglionic neuron
How does the PN Pathway work?
- All pre and post-ganglionic neurons are cholinergic -> release ACh
- ACh interacts with cholinergic receptors to slow body responses (“rest and digest”)
Name 3 body parts the PN pathway effects
- Eyes (constricts)
- Salivary Glands (increased saliva production)
- Heart (decreased heart rate)
Define “Adrenergic Pharmacology”
Drugs that block/increase SNS response
Define “Cholinergic Pharmacology”
Drugs that block/increase PNS response
List 3 effects of Alpha 1 Agonists
- Vasoconstriction of blood vessels
- Pupil dilation
- Decreased peristalsis in GIT (constipation)
What are Alpha 1 Agonists used for?
- Hypotension
- Nasal congestion/ red eyes
List 3 effects of Alpha 1 Antagonists
- Vasodilation of blood vessels
- Pupil constriction
- Increased peristalsis in GIT (diarrhoea)
List 3 effects of Beta 1 Agonists
- Increased heart rate
- Increased cardiac output
- Decreased digestion and GIT motility
Name 3 common side effects of Beta 1 Agonists
- Hypertension
- Tachycardia
- Constipation
What are Beta 1 Antagonists otherwise known as?
Beta blockers
List 3 effects of Beta 1 Antagonists
- Decreased heart rate
- Decreased cardiac output
- Increased GIT motility (diarrhoea)
What are Beta 1 Antagonists used for?
- Cardiac disease
- Hypertension
- Migraines
Name 3 common side effects of Beta 1 Antagonists
- Lethargy
- Insomnia
- Bradycardia
Explain the Pharmacology behind Beta Blockers?
- Bind to beta-adrenergic receptors, preventing the binding of adrenaline
- Can be selective (major organs) or non-selective (vascular smooth muscle)
Explain the Pharmacokinetics behind Beta Blockers
Absorption: Absorbed in GIT -> consistent blood levels Distribution: Must know how soon blood concentrations peak after administration Metabolism: Metabolised by body tissues Excretion: Via the renal system in urine
Explain Cholinergic Pharmacology
- As an agonist, stimulates cholinergic receptor
- As an antagonist, inhibits action mediated by cholinergic receptor
Name the 2 cholinergic receptors
- Nicotinic
2. Muscarinic
