Digestion/Liver Flashcards
Name the digestive tract organs. (6)
Mouth, esophagus, stomach, small intestine, large intestine, rectum
What are some accessory glands to the digestive tract?
Salivary glands, liver, gall bladder, pancreas.
Where do exocrine cells secret to?
Exocrine cells secrete into ducts.
What three organelles are found in large amounts in the exocrine gland cells?
Endoplasmic reticulum, mitochondria, secretory vesicles.
What do secretory vesicles contain?
Enzymes
What are secretory cells in groups called?
acini
What is in saliva?
Water, electrolytes, amylase, mucus, lysozymes (protects from pathogens)
What is in gastric juice?
Water, mucus, pepsin, HCl, rennin (chymosin)
What is in pancreatic juice?
Water, bicarbonate, amylase, lipase, carboxypeptidase, trypsinogen
Is the mouth basic, neutral, or acidic?
Slightly basic (pH 7-8)
What receptors are present in the stomach? (2) What do they detect?
Chemoreceptors detect peptide and Stretch receptors detect distention.
What is digestive juice secretion controlled by? (2)
Nerves/hormones
What can the sight or smell of food cause your brain to do?
Send nerve impulses to gland cells of the stomach wall to secrete pepsinogen and acid.
What is secreted when the brain sends signals via the vagus nerve to the duodenum?
Gastrin
What does gastrin stimulate the secretion of? From where?
Acid and pepsinogen from the stomach wall.
What inhibits the secretion of gastrin if pH in stomach falls too low?
Secretin and somatostatin
Why is gastric juice acidic? (2)
Low pH is optimal for pepsin and helps control pathogens.
What was William Beaumont able to figure out about gastric digestion?
That gastric digestion was both physical and chemical (not just chemical)
Who got the gunshot that allowed doctors to study his stomach?
Alexis St. Martin
What type of infection can cause ulcers?
Helicobacter pylori
How can someone with H. Pylori bacteria be treated?
A combination of antibiotics and proton pump inhibitors
How can you detect H.pylori?
H.pylori produces the enzyme urease so a urea breath test can be used. The patient is given some radioactive urea orally and see if they breath out radioactive carbon dioxide.
How do proton pump inhibitors work?
They irreversibly bind to ATPase or a protonpump to stop the acidic environment that is created by this proton pump.
What did Marshall and Warren discover? Why was it hard for their results to be accepted?
They discovered that antbiotics can cure ulcers but it was difficult for others to accept that as ulcers where known to be a result of excess stomach acid not a bacteria.
What does lipase do? Is it water-soluble or fat-soluble?
Lipase is a water soluble enzyme that is designed to break down a hydrophobic substance. Can only access the surface of lipids.
What does bile do to lipids? Why? Where is lipase made?
emulsifies lipids to increase the surface area. lipase is made in the pancreas
Draw the ileum.
What are the three parts of the small intestine in order?
Duodenum, jejunum, ileum
What does the epithelial cell of the villus contain?
Pinocytotic vesicles, mitochondria
What is the pinocytic vesicles for in the epithelial cell of the villus?
Contains fluid and dissolved minerals from the lumen
What function in the villus ensures most materials will pass through cells before the blood?
Tight Junctions
Draw the villi cross section.
What happens to lipids in the epithelial cell? What is the end product called?
They reassemble into triglycerides and become coated in proteins and chloresterol. This is called a lipoprotein complex.