Sanders: Enteric Nervous System Flashcards Preview

Block 3 Week 1 Meg > Sanders: Enteric Nervous System > Flashcards

Flashcards in Sanders: Enteric Nervous System Deck (24):

These cells lie within the gut mucosa and transduce luminal mechanical and/or chemical stimuli into the release of signaling molecules.

Enteroendocrine cells


These cells contain and secrete serotonin, are the largest population of enteroendocrine cells, and have the most widespread distribution.

Enterochromaffin cells


Enterochromaffin cells have both (blank) and (blank) capabilities.

chemosensitive; mechanosensitive


Describe the distribution of enterochromaffin cells in each crypt.

There are very few enterochromaffin cells in each crypt.


Primary sensory organ affecting GI motility.

EC cells


Enterochromaffin cells contain 90% of the body's (blank).

5-HT (serotonin)


How do epithelial cells "mop up" 5-HT following its release?

They have seratonin reuptake transporters (SERTs)


Most of the intrinsic and extrinsic primary afferent neurons that innervate the gut extend processes into the lamina propria of the mucosal layer where they can become exposed to (blank) released by enterochromaffin cells



These cells characteristically have large oval or round cell bodies with several long axonal processes emanating from them. Make up 20-30% of all enteric neurons.

Type II neurons


Describe the action potentials of AH/Type II neurons.

Fire an AP, which is followed by a long0lasting hyperpolarizing after-potential. Cannot fire subsequent APs right away.


What is the ionic mechanism for the after-hyperpolarizations in Type II neurons?

Ca+ channel activation


In AH neurons, a meal can cause excitatory post-synaptic potentials. Why is this important?

After a meal, it is important for your gut to "awaken" and amplify sensory input


Why is it difficult to localize pain in the gut?

AH neurons are all connected, so the sensory network is vastly distributed.


AH neurons synapse with each other by releasing (blank), which forms a self-reinforcing network.



These cells are characterised by the presence of short lamellar dendrites and a single long axon

Type I neurons


These cells have distinct electrical behavior: They fire action potentials throughout the duration of a long lasting depolarization

S/Type 1 cells


Compare the "spike" or action potential in S cells to that of AH cells.

S cells fire repeatedly and do not have long after-hyperpolarizations. They have fast action potentials. AH cells have a "hump" on their falling phase due to an influx of Ca+ ions.


Nerves with cell bodies within the gut

enteric nervous system


What do sympathetic nerves mainly do in the gut?

Regulate blood flow


The enteric nervous system contains two types of ganglia. What are they? Which one is mostly associated with motility? Which is mostly associated with regulation of blood flow, secretion, and absorption?

myenteric and submucosal; myenteric; submucosal


Excitatory: EC cells in the mucosa activate a (blank) in the myenteric plexus, which carries a signal to an (blank) in the oral direction, which activates an excitatory (blank), which releases ACh or neurokinins to cause (blank) of the circular muscle in the oral direction

IPAN (AH neuron); interneuron; motor neuron; contraction


Inhibitory: EC cells in the mucosa activate a (blank) in the myenteric plexus, which sends the signal through an (blank) in the anal direction to an inhibitory (blank), which releases NO or VIP to cause (blank) the circular muscle

IPAN; interneuron; motor neuron; relaxation


Produces excitation above the site of stimulation and relaxation below site of stimulation

Peristaltic reflex


AH neurons are appropriately named, because they filter action potentials coming in from the gut and send one strong AP followed by a period of (blank) in which no more APs are generated