GI - Pt 1 Intro/Gastrin Flashcards
What are the 4 major functions of the GI tract?
Neuro & Endocrine Regulation
Motility
Secretion
Digestion & Absorption
The vagus nerve innervates “everything” in the GI tract, from the top –> [] colon.
transverse
Crypts of [] are found in the gastic [] layer.
Crypts of Lieberkuhn are found in the gastic mucosa layer.
List the layers of the Gastric tissue from lumen to serosa
Gut Lumen
Mucosa (Epithelium/lamina propria)
Muscularis Mucosae
Submucosa
Muscularis Externa
Serosa
T/F
The muscularis mucosae has 2 layers of smooth muscle.
True
What 2 layers of muscle residein the muscularis mucosae?
Inner layer of circular SM
Outer layer of longitudinal SM
The submucosa contains, large [], [], [] vessels and the [] Plexus (or [] plexus)
The submucosa contains, large arteries, veins, lymphatic vessels and the submucosal Plexus (or Meissner’s plexus)
The muscularis externa contains an inner layer of [] SM and an outer layer of [] SM as well as the [] plexus (or [] Plexus)
The muscularis externa contants an inner layer of circular SM and an outer layer of longitudinal SM as well as the Myenteric plexus (or Auerbach’s Plexus)
The myenteric plexus mostly cause smooth muscle [] - responsible for the [] of food through the GI.
contraction, movement
If food doesn’t contact the wall of the intestine, it will [] [] absorbed.
If food doesn’t contact the wall of the intestine, it will not be absorbed.
Smooth muscle are connected by []. These receive signals from nerves release of NT via [] located near smooth muscle.
Smooth muscle are connected by nexi. These receive signals from release of NT via varicosities located near smooth muscle.
T/F
Myosin light chain kinase is always on and its action must be overcome by the action of myosin lightchain phosphatase to produce muscle relaxtion.
FALSE
- Flip it. Myosin light chain phosphatase is always on. MLCK must overcome MLCP to elicit a contraction.
The 2 main nerves forming the parasympathetic innervation of the GI tract are the [] nerve and the [] nerve.
The 2 main nerves forming the parasympathetic innervation of the GI tract are the Vagus nerve and the Pelvic nerve.
The Vagus Nerve:
- arises from the [] []
- Innervates –>
- esophagus to the [] colon
- [] [] in the upper 1/3 of the esophagus
- Uses [] NT and receptors for preganglionic/postganglionic innervation.
- arises from the medulla oblongata
- Innervates –>
- esophagus to the transverse colon
- Striated muscle in the upper 1/3 of the esophagus
- Uses cholinergic NT and receptors for preganglionic/postganglionic innervation.
Pelvic Nerve
- Arise from the [] spinal cord
- Innervates –>
- [] colon
- [] colon
- []
- Anal canal - specifically the [] [] sphincter
- Uses [] “NT/Receptors”
- Arise from the sacral spinal cord
- Innervates –>
- Descending colon
- sigmoid colon
- Rectum
- Anal canal - specifically the internal anal sphincter
- Uses cholinergic“NT/Receptors”
- The submucosal plexus and the myenteric plexus make up the [] [] system.
- This system is considered to be []-[] PNS fibers.
- The submucosal plexus and the myenteric plexus make up the enteric nervous system.
- This system is considered to be post-ganglionic PNS fibers.
The enteric nervous system [] [] on its own without para/symp innervation.
The enteric nervous system can operate on its own without para/symp innervation.
Describe the flow of innervation from Cranial Nerve X –> GI mucosa.
- Cranianl Nerve X –> Vagus Nerve
- Vagus Nerve –> Myenteric Plexus
- Myenteric Plexus –> Submucosal plexus
- Submucosal plexus to GI epithelium/glands/secreting cells.
What are the 4 prevertebral, synaptic ganglion in the sympathetic nervous sytem?
Celiac Ganglion
Superior mesenteric ganglion
Inferior mesenteric ganglion
Hypogastric ganglion
- In the sympathetic nervous system, postganglionic fibers arise from [] ganglia and synapse with the [] [] system of the GI tract.
- In the parasympathetic nervous sytem, the postganglionic fibers are synonymous with the [] [] system.
- In the sympathetic nervous system, postganglionic fibers arise from prevertebral ganglia and synapse with the enteric nervous system of the GI tract.
- In the parasympathetic nervous sytem, the postganglionic fibers are synonymous with the enteric nervous system.
A [] [] is a spontaneous wave of depolarization initiated from pacemaker cells of the smooth muscl (primarily [] muscle cells) at different points int the GI tract.
A slow wave is a spontaneous wave of depolarization initiated from pacemaker cells of the smooth muscle (primarily longitudinal muscle cells) at different points int the GI tract.
Basic Electrical Rhythms:
- Occur independent of [] innervation and at a fixed [] for a particular segment of the gut
- not a muscle contraciton but an incresased number of [] [] the wave may generate a muscle contraction.
- [] is unaffected by neural and hormonal activity
- May be influenced by [] and [] activity
- Occur independent of extrinsic innervation and at a fixed rate for a particular segment of the gut
- not a muscle contraciton but an incresased number of action potentials the wave may generate a muscle contraction.
- Rate is unaffected by neural and hormonal activity
- May be influenced by temperature and metabolic activity
An increase in temperature and metabolic activity, like in fever, would [] the BER and contraction of smooth muscle.
increase
