N28- ANS Orofacial Flashcards
what does the autonomic nervous system control?
body system except skeletal muscle
what does the autonomic nervous system regulate?
Essentially involuntary functions:
– Smooth muscle control – e.g. blood vessels
– Cardiac control – e.g. heart rate
– Glandular secretion
what aspects of autonomic nervous system can be trained?
urination
defecation
How does the sympathetic and parasympathetic devisions work?
OFTEN work in an opposing fashion to maintain homeostasis
what does parasympathetic coordinate?
coordinates the body’s basic homeostatic functions
what does sympathetic coordinate?
coordinates the body’s response to stress, associated
with fight, flight and fright reactions
what is a ganglion?
collection of nerve cell bodies located outside the CNS
what is a nucleus?
collection of nerve cell bodies located in the CNS
what is the position of the ganglion and the length of ganglionic fibres in the sympathetic pathways?
ganglion near the CNS so the pre ganglionic fibre is very short and post ganglion is long
what is the position of the ganglion and the length of ganglionic fibres in the parasympathetic pathways?
ganglion far away from the CNS so there is a long pre ganglionic fibre and a short postganglionic fibre
what transmitters are used In the sympathetic system?
- acetylcholine between pre ganglionic fibre and ganglion
- noradrenaline or acetylcholine between post ganglionic fibre and target tissue
In control of salivary secretion , how do sympathetic and parasympathetic work in relation to one another?
not reciprocal ( do not act against one another, one does not inhibit another, they just have different roles)
how does parasympathetics affect salivary secretion?
- increased secretion (watery secretions)
- vasodilation
how does sympathetics affect salivary secretion?
– α1 and β2 adrenergic receptors
– Increased secretion (viscous secretions)
– Vasoconstriction
what nerves are involved in parasympathetic control of salivary secretion?
Facial nerve VII: -submandibular and sublingual glands -(nasal and lacrimal glands) Glossopharyngeal nerve IX: -Parotid and lingual
what type of receptor is in parasympathetic control of salivary secretion?
muscarinic
what is a result of parasympathetic control of salivary secretion?
- responsible for most of the increase in volume of salivary flow
- small, variable increase in organic components
- contraction of myoepithelial cells
what is the antagonist in parasympathetic control of salivary secretion?
atropine
what is the target tissue transmitters in sympathetic control of salivary secretion?
- Noradrenaline in salivary glands
- (Note: ACh at some tissues e.g. sweat glands)
what is a result of sympathetic control of salivary secretion?
- DOES NOT INHIBIT salivary secretion
- Increased exocytosis of organic components
- Contraction of myoepithelial cells
Describe Frey’s syndrome?
Parotid surgery
Damage to auriculotemporal nerve :
-parasympathetic to salivary glands (ACh)
-sympathetic to facial sweat glands (ACh)
Regeneration of damaged nerves can lead to mixed nerves and misdirected which means salivary nerves can supply sweat glands. A salivary stimulant (gustatory) leads to activation of sweat glands -> sweating -> gustatory sweating
Describe the neural control of oro-facial blood vessels.
-Autonomic nerves :
sympathetic vasocontrictor
sympathetic vasodilator
-Afferent nerves:
axon reflex - triple response
what is the triple response?
Blunt trauma/scratch to skin
Red reaction or flush :
- capillary dilatation
- histamine release from damaged tissue
- LA has no effect
Flare:
- arteriolar dilatation
- increase blood flow
- local infiltration anaesthesia has abolishes flare
- distant nerve block does not abolish it
Wheal:
- increase capillary permeability
- histamine release
what is flare and wheal mediated by?
the axon reflex (pain lecture)
What is the hormonal control of oro-facial blood vessels?
- Systemic (real hormones) e.g. adrenaline
- local inflammation e.g. bradykinin
What is the metabolic control of oro-facial blood vessels?
- metabolites
- eg Co2, H+,vasodilation
what is the normal blood flow to pulp?
40-50ml/min/100g of tissue
what are the efferent autonomic nerves that supply pulp?
-sympathetic vasoconstrictor (alpha 1 receptors)
– sympathetic vasodilator (beta 2 receptors)
what do afferent nerves stimuli to dentine result in?
- pain
- increased blood flow
- axon reflex -> vasodilation increased -> increased capillary permeability -> increased sensitivity
what are local factors around the pulp?
bradykinin
what is the problem with pulp?
constant volume problem
Describe the constant volume problem?
- local vasodilation
- increased volume In an area
- increased pressure
- closing of vessels
- ischaemia
- death of pulp
NOT CORRECT:
new theory - pulp death due to static of blood in vessels
Describe the action, agonist and antagonist of alpha 1 adrenoreceptors.
- Action: smooth muscle contraction, vasoconstriction
- Agonist- adrenaline
- Antagonist- phentolamine
Describe the action, agonist and antagonist of beta 1 adrenoreceptors.
- Action: heart muscle contraction
- Agonist: adrenaline
- Antagonist : propranolol , atenolol
Describe the action, agonist and antagonist of beta 2 adrenoreceptors.
- Action: smooth muscle relaxation (e.g bronchioles)
- Agonist : adrenaline , salbutamol
- Antagonist : propranolol
Describe adrenaline in terms of dental pharmacology.
– α and β agonist
– vasoconstricor in LA solutions α1 effect
Describe phentolamine in terms of dental pharmacology.
– New – OraverseTM
– α1 antagonist – stops vasoconstriction
– reduces LA duration
Name a B2 agonist.
salbutamol
Name Beta blockers.
propranolol and atenolol
