Gastro Physiology Flashcards
During the intestinal phase of digestion, the typical fluid load to the jejunum is ______ L per day. Consisting of dietary water, saliva, gastric juice, pancreatic juice, intestinal secretion, and about 0.5 L of _____
7-10
Bile
Specializations of the GI tract to accomplish it’s functions
- Stomach acid and other digestive fluids
- The villi and microvilli of the small intestine
- The enteric nervous system
- The splanchnic circulation
- The colonic microbiome
What cells are responsible for ingesting foreign bodies entering the blood via the gastrointestinal tract?
Kupffer cells
In this type of swallowing the nasopharynx is closed by the soft palate, deflection of the food bolus by the epiglottis (away from the larynx), and relaxation of the upper esophageal sphincter
Involuntary
Endocrine functions of the pancreas
secrete the hormones insulin and glucagon
What 3 things work together to stimulate gastric acid formation
Gastrin, histamine, and acetylcholine
What type of highly phagocytic cells, located in the liver, are exposed to the portal blood flow and serve as a sentinel for antigens/bacteria arising from the intestine?
Kupffer cells
What is secreted in the pyloric gland area of the stomach?
Endocrine secretions:
Gastrin, Somatostatin, Histamine
The colon contains a longitudinal layer of smooth muscle called
Teniae coli
What keeps the stomach from digesting itself?
A mucus-bicarbonate barrier at the mucosal surface
In what condition do patients lack a functional Cl- channel in the luminal membrane of the pancreatic duct cells ultimately causing malabsorption?
Cystic Fibrosis
What must relax to allow the food bolus into the stomach?
Lower esophageal sphincter, controlled by autonomic nerves
GI circulation is also known as ______ circulation, and is most effected by the SNS
Splanchnic
Extraintestinal diseases that have been shown to be affected by the gut microbiome include:
- weight control (obesity)
- inflammatory bowel disease
- the general immune response (autoimmune diseases)
- resistance to infectious disease
What is the functional unit of the intestines?
Villus
Functions of the colon during the intestinal phase of digestion
Absorption of fluid
Transport of electrolytes
Storage and elimination of fecal waste
Most common cause of pancreatitis in women?
gallstones
Functions of bile
- emulsifies fats
- allows for excretion of hydrophobic molecules
- helps neutralize gastric acid (it’s alkaline)
What are the Motor functions of the stomach?
Reservoir for ingested food, mixing of ingested food, regulates the delivery of food to the small intestines at appropriate rate and consistency
About ____ liters of fluid is delivered to the colon per day, and approximately _____ liters are absorbed.
The maximum reabsorption capacity of the colon is ____ liters. If the total fluid load exceeds this, _______ occurs.
2
1.9
5
Diarrhea
Parts of the GI tract
mouth, esophagus, stomach, duodenum, jejunum, ileum, cecum, colon, rectum, anus
How do proton pump inhibitors work?
They bind and inhibit the H+/K+ -ATPase pump on the luminal surface of parietal cells
Major functions of the organs in the GI tract
- Nutrient intake and processing for absorption
- Water balance
- Protection from invasive organisms and toxins
- Endocrine functions mostly involving the regulation of nutrients (eg glucose and lipid metabolism, protein synthesis)
How is the food bolus moved through the esophagus?
smooth muscle peristalsis, coordinated by the enteric nervous system
In what ways do non-pathogenic bacteria benefit the GI system?
- provide beneficial metabolic functions
- provides increased resistance to pathogens/allergens
What stimulates the feedback loop to shut off secretion of gastric acid
Somatostatin
If bacterial antigens survive the acid in the stomach and bind to the luminal surface of the distal small bowel, they stimulate this type of lymphocytic cell to circulate and populate all of the musical tissues of the body?
IgA-secreting plasma cells
Sympathetic noradrenergic activity in the enteric nervous system has what effect in the GI tract
decreases intestinal smooth muscle activity and causes sphincters to contract
In Splanchnic circulation, all the blood from the GI tract drains to the liver via
hepatic portal vein
What stimulates and releases Gastrin in the stomach?
Stimulated by stomach stretch, released by Gastrin-releasing peptides (GRP) by enteric nervous system
Contraction of the gallbladder occurs during what phase of digestion?
intestinal
in response to a meal
What phase of gastrointestinal response involves gastrin, histamine, and acetylcholine that bind to parietal cells to stimulate gastric acid production?
Gastric phase
What is involved in cobalamin absorption?
Intrinsic factor
The major network of nerve fibers involved with secretions in the gastrointestinal tract
Submucous plexus (Meissner)
What must relax to allow food into the esophagus?
Upper esophageal sphincter, controlled but the extrinsic nerves
What is involved in the Exocrine functions of the stomach?
Water- dissolve & dilute ingested food
Acid (HCl)- denature dietary proteins and sterilize the meal
Enzymes (pepsin & gastric lipase)- protein & fat digestion
Intrinsic factor- a glycoprotein that is necessary for B12 absorption
Mucus-bicarbonate barrier- protects against corrosive properties of the gastric juices