DAY 2: digestive system Flashcards
Q: What is the main purpose of the digestive system?
A: To convert macromolecules (polymers) into monomers that cells can use.
Q: What is the role of mechanical digestion in the mouth?
A: Teeth tear and grind food to increase its surface area, exposing more of it to enzymes.
Q: How does saliva aid in digestion?
A: It moistens food, making it easier to swallow, and contains amylase, which breaks down carbohydrates.
Q: What is the function of the epiglottis?
A: It prevents food from entering the windpipe during swallowing.
Q: What is the function of the esophagus?
A: It is a muscular tube that transports food from the mouth to the stomach through peristalsis.
Q: What is peristalsis?
A: Muscle contractions that move food through the digestive tract.
Q: What is the role of the cardiac sphincter?
A: It controls access to the stomach and prevents acid reflux into the esophagus.
Q: What are rugae, and what is their function?
A: Ridges in the stomach lining that allow it to expand and help mix food with gastric juices.
Q: How is pepsinogen activated, and what does it do?
A: It is converted to pepsin in the presence of HCl and digests proteins into amino acids.
Q: What is chyme?
A: The semi-liquid mixture of partially digested food and gastric juices in the stomach.
Q: What is the function of the duodenum?
A: It is the main site of chemical digestion and neutralizes stomach acid with bicarbonate ions.
Q: Which enzymes does the pancreas produce, and where are they secreted?
A: Amylase, lipase, trypsin, and erepsin; secreted into the duodenum through the pancreatic duct.
Q: What is bile, and where is it produced and stored?
A: Bile is produced by the liver, stored in the gallbladder, and emulsifies fats in the duodenum.
Q: How does bile assist in fat digestion if it is not an enzyme?
A: It emulsifies large fat globules into smaller droplets, increasing the surface area for lipase.
Q: What is the function of villi and microvilli in the jejunum?
A: They increase surface area for absorption and contain capillaries that transport nutrients.
Q: What role does the ileum play in digestion?
A: It absorbs vitamins and remaining monomers and connects the small intestine to the large intestine.
Q: What occurs in the large intestine?
A: Water is reabsorbed, and bacteria help produce vitamins from indigestible substances.
Q: Where is stool formed and stored?
A: Formed in the large intestine, stored in the rectum, and evacuated through the anus.
Q: Why is no chemical digestion necessary in the large intestine?
A: Most nutrients have already been absorbed, and its main role is water reabsorption and waste processing.
