Autonomic Nervous System Flashcards
What does the central nervous system consist of?
- Brain
- Spinal cord
- Retina
- CNII
What does the peripheral nervous system consist of?
- Spinal nerves
- Cranial nerves (except CNII)
- Autonomic nervous system (sympathetic and parasympathetic)
- Somatic sensory and motor nerves
What does the sympathetic nervous system do to:
- Pupils
- Heart
- Blood vessels
- Gi transit speed
- Urinary and anal sphincters
- Bronchi
- Sweat glands
- Dilate pupils
- Heart: increase speed and contractility
- Constrict blood vessels
- Decrease GI transit speed
- Dilate bronchi
- Increase activity of sweat glands
- Constrict urinary and anal sphincters
What does the parasympathetic nervous system do to:
- Pupils
- Heart
- Bronchi
- GI transit speed
- Sphincters
- Salivary glands
- Sweat glands
- Genitals
- Constrict pupils
- Reduce heart rate and contractility
- Constrict bronchi
- Increase GI secretions and transit speed
- Relaxes sphincters
- Increases the activity of salivary glands
- Decreases activity of sweat glands
- Genitals: sexual arousal
What do spinal nerves contain?
Sensory
Motor
Sometimes autonomic fibres
Which spinal nerves contain autonomic nerve fibres?
What can be seen in the spinal cord around these nerves?
- T1-L2
- S1-S4
Lateral horn can be seen in grey matter
What are the neuro transmitters used in the sympathetic nervous system?
Which receptors do they act on?
What is the exception to this?
Preganglionic fibres: Ach (nicotinic receptors)
Postganglionic fibres: Noradrenaline (alpha or beta)
EXCEPT: sweat glands and chromaffin adrenal medulla:
- ACh activated muscarinic receptors
What neurotransmitters are used in the parasympathetic nervous system?
What receptors do they act on?
Preganglionic: ACh (Nicotinic)
Post-ganglionic: ACh (Muscarinic)
At what vertebral level does the spinal cord terminate in an adult?
- L1-L2
Where do sympathetic spinal nerves emerge from the spinal cord?
Emerge from the spinal cord only with spinal nerves T1-L2
How does the sympathetic chain communicate with spinal nerves?
Via rami communicans
- White ramus communicans: only found leaving T1-L2 spinal nerves (preganglionic sympathetic neurons passing into the sympathetic chain ganglion)
- Grey ramus communicans: postganglionic sympathetic fibres passing from the sympathetic ganglia into the spinal nerve
What is Horner’s syndrome?
What are the symptoms?
What can it be caused by?
Loss of sympathetic supply to the head:
- Anhydrosis
- Ptosis
- Vasodilation
- Pupil constriction
Caused by:
- IV cannulation of internal jugular vein
- Pancoast tumour of the apex of the lung (compression of sympathetic chain)
What sympathetic chain ganglia are in the neck?
- Superior cervical
- Middle cervical
- Stellate (near lung apex)
What do the pre-aortic ganglia supply?
What are they supplied by?
Where are they found?
Pre-aortic ganglia are supplied by the splanchnic nerves.
They include:
- Coeliac (T5-T9) → Foregut
- Aorticorenal
- Superior mesenteric (T10-T11) → Midgut
- Inferior mesenteric (T12-L1) → Hindgut
Found around the blood supply to the gut tube
Describe the sympathetic supply to the gut tube
Coeliac ganglion (T5-T9) → Foregut
Aorticorenal ganglion
Superior mesenteric ganglion (T10-T11) → Midgut
Inferior mesenteric ganglion (T12-L1) → Hindgut
What do post-ganglionic parasympathetic neurons of CNIII, VII, IX and X travel with?
CNX
