GI 1 Flashcards
quiz
What are the accessory organs of the digestive system
salivary glands, pancreas, liver, gallbladder
Describe the order of the alimentary canal
mouth, esophagus, stomach, small intestine, large intestine
Peritoneum
serous membranes within the abdominal cavity
what is the purpose of the peritoneum
supports blood vessels, nerves, and lymphatic vessels
describe the parietal peritoneum
inside the surface of the body wall
describe the visceral peritoneum
surface of the internal organs
Peritoneal fluid
produced by serous membrane lining, provides essential lubrication allowing sliding without friction or irritation
intraperitoneal organs are located
within the peritoneal cavity
retroperitoneal organs are located…
behind the peritoneum
What is the function of the mesentery
prevents the GI tubes from getting tied up
What disease does the mesentery play a role in?
Crohn’s disease- chronic inflammation of the GI tract
What is the order of the GI histological layers? (lumen to outer)
transporting layer (epithelial), defense layer (immune and blood vessel cells), muscle layers (muscle cells), protection layer (connective tissue)
What 3 layers make up the mucosa
mucosal epithelium, lamina propria, muscularis mucosae
Describe the mucosal epithelium
enterocytes, endocrine and exocrine signals; GI stem cells
what do enterocytes do
transport (take substances into cells and also secrete substances out)
describe the lamina propria
connective tissue contains nerve fibers, vessels, and lymph nodes; wondering immune cells
describe the muscularis mucosae
thin layer of smooth muscle, shape intestinal folds, move villi
Which layer is the submucosa
defense layer
describe the submucosa
loose connective tissue containing larger blood and lymph vessels (transporting absorbed nutrients)
What is the submucosal plexus
Meissner’s plexus; nerve supply to the muscularis mucosae
The Muscularis Externa is what layer of the GI tract?
muscular layer
what makes up the muscularis externa
2 layers of smooth muscle: inner layer: circular, outer layer: longitudinal
myenteric plexus: located between 2 muscle layers
peristalsis
move food along; mainly in the esophagus
segmentation
mix food and break it down; mainly in the small and large intestine
GI smooth muscle contraction frequency is set by:
basic electrical rhythm
(slow waves 3-20 waves; set by pacemaker cells)
What are the pacemaker cells in the GI called
interstitial cells of Cajal; modified smooth muscle cells that lie between muscle and nerve plexus
What can influence contraction frequency
mechanical or chemical input
what are features of the enteric nervous system that are similar to the CNS?
integrating center, glial cells, respond to many neurotransmitters and GI peptides to affect motility and secretion
Elevated VIP (Gs coupled pathway) has been found in inflammatory bowel diseases, irritable bowel syndrome, what are some possible symptoms based on your knowledge on the receptors involved?
decreased motility (no smooth muscle contraction); increased secretion (vasodilator)
Functions of saliva
softens and lubricates food, chemical digestion, taste, protection
The acinar cells secrete what kind of fluid
a fluid that resembles extracellular fluid; isotonic; low in K, isotonic levels of Na+, Cl-, bicarb
in the ductal cells, what is absorbed into the blood and what is secreted out of the blood into the oral cavity
absorbed= Na+, Cl-
secreted= bicarb, K+
during salivary stimulation…
ductal modification reduces, bicarb remains high by the action of secretagogues
What is the resting pressure in the gastroesophageal junction
30 mmHg
What are substances that reduce gastroesophageal junction pressure?
alcohol, caffeine, cigarette smoke, chocolate
What is a pathological condition that is caused from a sphincter (esophageal) failing to close
GERD: gastroesophageal reflux disease; causes heartburn because stomach acid is traveling towards the esophagus
What are conditions that increase the pressure in the gastroesophageal junction?
diseases and medications
What is a pathological condition that is when the lower esophageal sphincter cannot relax (constricted)
Achalasia; difficulty swallowing, regurgitation of undigested food, chest pain because of the disruption of peristalsis
What can cause achalasia?
degeneration of the nerve cells that innervate esophageal muscles
How will VIP affect smooth muscle?
VIP will relax smooth muscle
How will NO affect smooth muscle?
it will relax smooth muscle
