GIT Neuro Flashcards
Which part of the spinal cord are sympathetic and parasympathetic nerve fibres innervating the GIT located?
Lateral horn (grey matter)
Which parts of the GIT are supplied by the Vagus nerve?
Fore and mid gut (until proximal 2/3 of transverse colon)
Which parts of the GIT are supplied by the pelvic splanchnic nerve?
Proximal 2/3 of transverse colon onwards
The internal anal sphincter is under (autonomic/somatic) control and is innervated by the _________________________.
Autonomic: Pelvic Splanchnic nerve (Parasympathetic)
The external anal sphincter is under (autonomic/somatic) control and is innervated by the _________________________.
Somatic: Pudendal nerve
What are 2 types of interconnected tubular neuronal systems in the enteric nervous system?
1) Myenteric (Auerbach’s) plexus
2) Submucous (Meissner’s) plexus
What are 5 sympathetic effects on the GIT?
1) ↑salivation
2) ↑activity of stomach/intestines
3) ↑activity of pancreas
4) ↑stimulate gall bladder
5) ↓glucose release
What are 6 parasympathetic effects on the GIT?
1) ↓salivation
2) ↓activity of stomach/intestines
3) ↓activity of pancreas
4) ↓inhibit gall bladder
5) ↓glucose release
6) ↑adrenaline/NE from adrenal gland
What are the parasympathetic effects of cholinoceptors on effector organs?
M1: Stomach
- ↑Stomach acid secretion via Enterochromaffin-like cells
M2: Gallbladder, GIT
- Gall bladder contraction
- GIT: inhibit smooth muscle relaxation
M3: Salivary glands, GIT
- ↑Saliva production
- ↑GI motility and secretion
Where are the cell bodies of preganglionic sympathetic neurons innervating the GIT?
Lateral horn (Intermedio-Lateral Nucleus) (T1-L2)
Where are the cell bodies of preganglionic parasympathetic neurons innervating the GIT?
C3,7,9,10: brainstem nuclei
S2-4: Lateral horn
Where are the cell bodies of postganglionic parasympathetic neurons innervating the GIT?
Postganglionic Ganglia
Where are the cell bodies of postganglionic sympathetic neurons innervating the GIT?
Paravertebral ganglia
Pre-vertebral ganglia (eg. celiac plexus, superior mesenteric ganglia)
What is a autonomic nerve plexus?
Network of sympathetic and parasympathetic (with occasional ganglia) which transmit visceromotor and viscerosensory fibers to and from viscera.
Which nerve(s) supply derivates of the foregut?
Greater splanchnic nerve (T5-T9)
Which nerve(s) supply derivates of the midgut?
Lesser splanchnic nerve (T10-11)
Which nerve(s) supply derivates of the hindgut?
Least splanchnic nerve (T12)
What are 6 types of splanchnic nerves?
1-3) Thoracic: Greater, lesser, least splanchnic nerve
2) Lumbar splanchnic nerve
3) Sacral splanchnic nerve
4) Pelvic splanchnic nerve
Which of the splanchnic nerves carry sympathetic fibres?
1-3) Thoracic: Greater, lesser, least splanchnic nerve
4) Lumbar splanchnic nerve
5) Sacral splanchnic nerve
Which of the splanchnic nerves carry parasympathetic fibres?
Pelvic splanchnic nerve
In which layer of the intestinal wall are myenteric plexus located?
Muscularis (between circular and longitudinal)
In which layer of the intestinal wall are submucous plexus located?
Submucosa
Sensory afferent nerve fibres for visceral reflexes in the GIT follow _________________ and have ganglion ________________.
Visceral reflex:
Fibres: follow parasympathetic nerves
Ganglion: Inferior Vagal Ganglion
Sensory afferent nerve fibres for visceral pain in the GIT follow _________________ and have ganglion ________________.
Visceral pain:
Fibres: follow sympathetic nerves
Ganglion: Dorsal root ganglia
