Digestive System + Hormones Flashcards
Where are proteins broken down?
in the stomach and duodenum
Amylase
breaks down starch
Lipase
breaks down lipids
Lysosyme
antimicrobial enzyme that kills some bacteria in the mouth
What is broken down in the mouth by saliva?
carbs and lipids
peristalsis
smooth muscle contracts to move food
bolus
moves from the mouth through the esophagus to the stomach
What causes GERD?
a weakened lower espohageal sphincter allows food to move backwards
Which cells secrete gastric acid?
parietal stomach cells
What is in gastic acid?
HCl and salts
What cells secrete pepsinogen?
chief cells of stomach
What does the stomach absorb?
Vitamin B1 and water by releasing intrinsic factor
How do the acidic conditions not degrade the stomach?
mucous epithelial cells secrete bicarbonate at the stomach’s lining to neutralize the acid
What causes peptic ulcers?
H. pylori bacteria found in some members of the population
What moves into the small intenstine?
chyme
Villi
create folds in the small intestine to increase surface area
made of enterocytes
Enterocytes
epithelial cells that line the intestines
contain lots of microvilli brushes
What are the parts of the small intestine in order?
duodenum, jejunum, ileum
What happens when chyme reaches the duodenum?
small intestine secretes secretin
secretin tells pancreas to secrete bicarbonate
bicarbonate neutralizes the acidic chyme
CCK
secreted by the small intestine
stimulates release of digestive enzymes from the pancreas and bile from the liver
Where is bile produced and stored?
bile is produced in the liver and stored in the gallbladder
What does bile contain?
bile salts, pigments, cholesterol
bile salts
amphipathic and can form a miscelle around lipids and aqueous environment
What is lipid emulsification? What molecules conduct it?
breaking down lipids to expose the greatest surface area to hydrolytic enzymes
bile salts carry out lipid emulsification
How does liver detox?
through the hepatic portal
hepatic portal
a system of blood vessels with a capillarly bed at each end
blood from small intestine enters the hepatic portal before entering the body, allowing for detox
Digestive enzymes secreted by pancreas
pancreatic amylase
pancreatic lipase
proteases
How do digestive enzymes move to small intestine from pancrease?
alkaline fluid with the enzymes is secreted into the pancreatic duct
exocrine function of pancreas
release enzymes into ductal system
endocrine function of pancreas
release hormones into bloodstream
Brush border enzymes
secreted by enterocytes
further break down molecules prior to absorption
What are the parts of the large intestine in order?
cecum, colon, and rectum
Where is the appendix?
attached to the cecum of the large intestine
What is the main function of the colon?
to absorb H2O from chyme
What is feces mostly composed of?
cellulose and water
Leptin
secreted by adipose cells and promotes fullness
triggered when adipose cells have increase in fatty acid synthesis
Ghrelin
secreted by pancreas and stomach when stomach is empty
triggers appetite
G-cells
secrete gastrin which tells parietal cells to produce gastic acid
S-cells
secrete secretin in duodenum and tells pancreas to secrete bicarbonate
somatostation
halts all pro-digestion hormones, stalls stomach emptying, halts release of insulin and glucagon, inhibits growth hormone
enteric nervous system
branch of autonomic nervous system involved in digestion
sucrose is broken into
glucose and fructose
maltose is broken into
two glucoses
lactose is broken into
glucose and galactose
What causes lactose intolerance?
no lactase in small intestine
so, lactose is broken down in large intestine by microbiome which produces gas
Where does pepsin cleave?
between hydrophobic or aromatic sites
Where does trypsin cleave?
at lys or arg
Where does trypsin work?
in duodenum
How are carbs absorbed into the bloodstream?
through secondary active transport
first, Na/K pump creates Na+ concentration gradient
when Na+ moves down its concentration gradient, it takes carbs with it
Which vitamins are water soluble?
vitamin B and C
Vitamin A
retinol
important for vision
Vitamin D
regulates Ca2+ and phosphate concentrations in blood
synthesized by skin from UV exposure
What is the functional form of Vitamin D called?
calcitriol
Vitamin K
needed for blood clotting
Vitamin C
absorbic acid
required for collagen synthesis
