Chapter 4: Human Digestion & Absorption Flashcards
What is the role of the digestive system?
break down and digest food
GI tract flow:
mouth -> esophagus -> stomach -> small intestine -> large intestine -> rectum -> anus
List the accessory organs:
liver, pancreas, gallbladder
Nutrients must pass through the wall of what tube to be absorbed in the body?
Alimentary canal
What is a sphincter, where are they located, and what is their function? List the sphincters in
order from mouth to anus.
ring-like muscles that control the flow of contents
lower esophageal, pyloric, sphincter of Oddi, ileocecal valve, anal sphincter
Segmentation vs. peristalsis
segmentation = back & forth movement peristalsis = moves food down
What are digestive enzymes and where are they produced?
speed up reactions to cause digestion, produced by mouth, stomach, small intestine, & pancreas
Hydrolysis reactions are needed to break down _________.
large molecules
Where does digestion begin? What enzyme is present?
the mouth, saliva
Describe the process of swallowing. What is the epiglottis?
bolus -> esophagus, prevents food from entering trachea
The food enters the _____ next through the ______ located between the _______.
stomach, esophageal sphincter, esophagus & stomahch
What is chyme? How does it aid in digestion?
mixes stomach contents w/ secretions
What is the role of mucus in the stomach and what cells secrete it?
the stomach secretes mucus to protect the stomach from digestion by HCl & pepsin, secreted by mucus cells
Small intestine is the major site of _____.
absorption
Describe the surface of the small intestine. How does it move chyme?
increases surface area, mixed chyme with digestive juices & brings nutrients into contact with villi
Villi are lined with ________, which___________.
enterocytes, secrete enzymes & absorb nutients
Digestion in the small intestine depends on secretions from _______.
brush border
Where are the secretions from the liver, gallbladder, and pancreas delivered?
the duodenum (top section of SI)
What does the liver produce to help with digestion? How does it help? Where is it stored?
bile, aids in fat digestion, stored in gallbladder
What does the pancreas produce? What does the secretion do?
sodium bicarbonate = neutralize chyme
amylase = digest starch
lipase = digest fat
proteases = digest protein
How do fat-soluble vitamins enter circulation? Water-soluble?
fat-soluble = lymphatic system
water soluble = cardiovascular system
The _______ empties into the ______ through the _______ sphincter between the
________.
the small intestine, large intestine, ileocecal valve, small & large intestine
What reduces the number of beneficial bacteria?
antibiotics
What are probiotics? Prebiotics? How do they help?
probiotics = bacteria & yeast prebiotics = food for probiotics
control bacteria, synthesise vitamin K, aid in lactose digestion
