Digestive System - Accessory Organs

Question 1

Homeostasis

Answer 1

Steady internal state (keeps conditions constant) –> achieved through negative feedback

Question 2

Salivary Glands

Answer 2

Secrete saliva made up of two types of secretions:
Parotids secrete water and enzymes (amylase)
Buccal glands secrete mucus

Question 3

Pancreas and pH

Answer 3

Pancreas protects the small intestine from stomach acids
(Acid of pH 2.5 in duodenum from chyme)
Secretin hormone released from intestinal wall and absorbed into the bloodstream which triggers the release of bicarbonate ions from the pancreas. This neutralizes the hydrochloric acid to a pH of 9, deactivating the pepsin

Question 4

Pancreas and Proteins

Answer 4

Pancreas releases trypsinogen that converts to trypsin which breaks down proteins

Question 5

Pancreas and Lipids

Answer 5

Pancreas secretes lipases enzymes which break down fats
(Lipids often enter intestines as fat globules, so the liver and its secretions need to physically digest (emulsify) the fats before the enzymes can chemically digest them)

Question 6

Liver

Answer 6

Produces/synthesizes bile (about 1 L/day) –> bile helps to break down fats

Question 7

Gallbladder

Answer 7

Muscular sac that stores and concentrates bile from the liver –> contracts to send bile to the duodenum

Question 8

Bile

Answer 8

Made in the liver, stored in the gallbladder –> enters intestines through bile duct
Functions: acts as detergent to emulsify fats and helps with absorption of fats
Gallstones can occur when cholesterol precipitates out of bile to form crystals