enteric nervous system Flashcards
Intestine
Microvilli inside
Lots of muscle layers
Submucosa - nerve endings come in
Epithelial cells
Line the lumen
Enterocytes - absorb glucose, amino acids etc from food.
Goblet cells - secrete mucus, and protect lining from acid.
Tuft cells
enteroendocrine cells - release hormones.
Relationship with CNS
ENS can function independently - no dependance with brain or other systems
Enteric neurocircuitry
Ens definition
Sensation - afferents
Integration - ganglia
Instruction - efferents
Presence of neurons and glia organised in ganglia arranged as 2 or more.
Structure
NOT AS REDUCTIONIST IN REALITY
Myenteric plexus - Dense bundles of neurons. GI motility. ‘s neurons’ fast synaptic input. Motor neurons.
Circular muscle.
Submucosal plexus - Less concentrated populations of neurones. Secretory functions, absorbtion and blood flow regulation. ‘AH neurons’ Prolonged hyperpolarisation. Intrinsic primary afferent neurons.
Functions of intestines
DIgestion and absorbtion
Secretion
Mobility/segmentation
Mucus
Immune system
Peristalsis
Gastrointestinal motor patterns involving partial or total acclusion of the lumen.
Moves intestinal content to rectum.
Mixes luminal contents
Peristalsis Reflex
Contraction is orchestrated by the ENS oral to the bolus.
relaxation is orchestrated by the ENS anal to the bolus.
Acetecholine and 5HT are key neurotransmitters.
5-HT in peristalsis
Cells that produce 5HT are stretch receptors. Enterochromaffin cells. As mechanical stress is applied, greater electrical signal produced.
Peizo2 is a sensory transduction channel which is key.
ENS in disease
ENS could give rise to CNS disorders, as anatomically the same.
Parkinsons disease
Studying the ENS
Optogenetic actuators + sensors.
Light evoked responses and cell activity.
Photon/electron microscopes.
