Digestion - Lesson 2 Flashcards
Describe the Stomach
a J-Shaped muscular bag that stores the food you eat, breaks it down into tiny pieces.
How does the stomach work?
It mixes food with digestive juices - called gastric juices - that contain enzymes that break down proteins and lipids
Where do gastric juices come from?
The gastric glands of the stomach
What makes up gastric juices?
HCl - Hydrochloric acid - it kills bacteria but also activates the enzyme pepsin
Mucus - coats the stomach wall to protect it from HCl
Pepsinogen - an inactive enzyme (when present with HCl, pepsinogen is activated) The active form is called Pepsin
What is Pepsin
an emzyme that breaks down protein in the food you eat into smaller peptides and amino acids
How does a stomach ulcer occur?
when pepsin effectively “eats” away at the protein in the cells of your stomach lining.
The mucus lining of your stomach deteriorates exposing the stomach wall to HCl and Pepsin
The mucus deteriorates often because of a bacterial infection (H. Pylori)
What is Chyme?
The food that leaves the stomach and heads into the small intestine
What is the pyloric sphincter?
It is the sphincter at the end of the stomach (and beginning of the small intestine)
What is the first part of the small intestine called?
the duodenum
What happens as chyme enters the duodenum?
The liver increases the production of bile and causes the release of bile from the gall bladder.
Bile enters the duodenum through a duct and emulsifies fat (breaks large fat molecules up into smaller fat molecules)
What is emulsification?
It breaks the larger fat molecules down into smaller fat molecules.
It increases the surface area
What is the pancreas?
an important organ in digestion. It secretes pancreatic juice into the duodenum
What does pancreatic juice contain?
Sodium bicarbonate - increases pH to a slightly basic level
Amylase - digests carbohydrates
Lipase - breaks down fats
Trypsin - Further breaks down proteins
What are intestinal juices?
juices that are secreted by the cells lining the small intestine.
What do intestinal juices contain?
Enzymes that are needed to further break down molecules
Peptidases - further break down proteins into amino acids
Maltase - an enzyme that breaks down maltose into glucose
Lactase- an enzyme that breaks down lactose into glucose
Nucleases - enzymes that break down nucleic acids into nucleotides
