Nibbs GI

nibbs06's version from 2015-04-15 01:41



Question Answer
What’s Intrinsic Control?Enteric Nervous System (Plexuses)!
What innervates the skeletal & smooth muscles of the esophagus?Somatic nerves from NA; & Autonomic Nerves from DMN & from the ENS
The circular & longitudinal muscles of the GI are controlled by?The Myenteric Plexus
At rest, how does the LES have high tone?Via Myogenic mechanisms; intrinsic ability to maintain tone
LES opens via?Caudal DMN nerves releasing NO- via the inhibitory pathway
LES closes via what two pathways?Rostral DMN nerves releasing ACh via the excitatory pathway & myogenic mechanisms; Intrinsic pathway.
The main mechanism for regulation of LES tone is?Myogenic Mechanism
Without any nerve innervation, the tone of the LES is?High; only the myogenic mechanism will then be present
What type of mechanisms keep the LES closed?Myogenic Mechanism, cDMN of Vagus, Hormonal & Anatomical Mechanisms via the Crura muscle
What is a Sliding Hiatal Hernia & what is its consequence?It is when the LES ascends, superior the the diaphragm and enters an area of negative pressure, the thoracic cavity. Any Intra-Abdominal Pressure that acts onto the stomach, will no longer act onto the LES; the Pressure difference b/ween the stomach and LES will cause stomach contents to squirt up into the esophagus!
What are the effects of Achalasia?no peristalsis in smooth muscle & LES won’t open; Loss of the Inhibitory pathway/neurons


Question Answer
Inability to elevate Hyoid bone is regulated by what nerves? Its inability to elevate will hinder and affect the ___ reflex.Cranial Nerves; Swallow Reflex.
How does Myasthenia Gravis affect the swallowing reflex?ACh will not bind to the nicotinic receptors @ the NMJ very well & it will prevent normal muscular contraction.
The 3 purposes of mastication areBreaks up the food, initiate digestion of carbs/fats via Amylase & Lingual Lipase from the Salivary and Tongue Glands, and uses Mucin-Salivary Glands to make it suitable for swallowing by forming the food into a bolus.
How is Chewing considered a semi-autonomic act?It is primarily an unconscious act, but can be mediated by higher conscious input;
Parafunctional habits require a ___ in order for them to cease, because ___conscious act because things like bruxism, tongue thrusting, etc are a result of excessive input to the central pattern generator, causing the unconscious act of mastication that cannot be consciously prevented.
The feedback signal, which determines the duration & force of the chewing muscles, is sent to the Central Pattern Generator from ___ nervesProprioceptive Nerves.
What are the three phases of swallowing?Oral, Pharyngeal & Esophageal Phase.
The UES relaxes during what phase of swallowing?pharyngeal phase; bolus is propelled from mouth, through pharynx & to the esophagus
The failure of what event potentially leads to Aspiration Pneumonia to occur in dysphagia patients? Either the closing of the vocal folds or pulling the epiglottis up so that it covers the trachea.
What causes the swallowing reflex to begin and what phase does it occur in?Bolus touches tactile receptors of pharynx, the brain sends info via vagal afferent to the NTS and then to 1 of 2 areas based on the location of control; Pharyngeal Phase
If we wanted to control the upper portion of the esophagus, where would the signal go to as it leaves the NTS?NA → Somatic Motor Fibers → Target (NMJ of striated muscle & UES of upper esophagus)
The initial part of swallowing, requires ___(intrinsic/extrinsic) ____(afferent/efferent) nerve, from the ___(NA/DMN) to cause contraction of at the UES & to cause peristalsis. extrinsic; afferent; NA
If we wanted to control the lower portion of the esophagus, where would the signal go to as it leaves the NTS?To the DMN → Visceral Motor Neurons → Ganglia Cells of the ENS in the lower part of esophagus & UES.
What’s the difference b/ween primary and secondary peristalsis?secondary peristalsis is coordinated by the swallowing center, while primary is under neural vagal control. Secondary is occurs under localized neural control (e.g., when food is stuck in the lower part of the esophagus or by the acid due to gastric reflux)
What is required in primary peristalsis that isn’t in secondary peristalsis?Primary requires an intact extrinsic innervation, while secondary may occur in the absence of extrinsic innervation, in that case it is mediated by the ENS
What nervous system is dominant in the control of swallowing?CNS
In swallowing, Sympathetic supply is via what post-ganglionic neurons?cervical ganglia & thoracic paravertebral chains.
In peristalsis, the longitudinal muscles behind the bolus are ___ & they are ___ in front of itrelaxes & contracts.