Chapter 9
What is the function of the large intestine?
Absorb water and salt
The large surface area of the small intestine is important for what process?
Absorption of nutrients
Why is the pH of the small intestinal contents normally slightly basic?
Because pancreatic juice contains sodium bicarbonate
What is the lumen defined as?
Central space
After their absorption form the gut lumen, monoglycerides and fatty acids are rejoined in the villi epithelial cells, forming lipid droplets called:
Chylomicrons
What is the function of the pancreas?
Contains digestive enzymes, sends them to the small intestine, produces insulin and secretes it into blood
What is the function of the stomach?
Control movement of food into small intestine, digestion of proteins, storage of food
During chemical digestion, what protein molecules hydrolyze food macromolecules?
Digestive enzymes
A duct brings bile from the gallbladder directly into the...
Duodenum
What is the function of bile?
Emulsifies fats
What is the structure that prevents swallowed food from entering the lungs?
Epiglottis
Heartburn is caused by the irritation of what tract?
Esophagus
What is the component of the food passageway that leads away from the pharynx?
Esophagus
What are symptoms of lactose intolerance?
Excessive gas, bloating, abdominal cramps
Gastric juice is produced by...
Gastric glands
When some of the stomach contents infiltrate the esophagus, it is commonly known as the condition called...
Heartburn
What is the ultimate purpose of digestion?
Hydrolyze food
Organic macromolecules are too big to cross the plasma membrane of cells, so they need to be what?
Hydrolyzed
Alcohol can be absorbed by the stomach because...
It is fat soluble
What enzymes are involved in the digestion of carbohydrates?
Lactase and amylase
In the small intestine, each villus contains blood capillaries and a small lymphatic capillary called what?
Lacteals
What are the digestive enzymes produced by the pancreas?
Lipase, amylase, and nuclease
From innermost to outermost, what are the layers of the GI tract wall?
Lumen, mucosa, submucosa, muscularis, serosa
What is the function of amylase?
Made by salivary glands or pancreas; digests starch
What is the function of lipase?
Made in the pancreas; digests lipids
What is the function of pepsin?
Made in the stomach; digests proteins
What structures increase the surface area of the small intestine?
Microvilli
What is the function of the small intestine?
Mixes chyme with digestive enzymes, absorbs nutrients, secretes hormones into blood
Where does chemical digestion begin?
Mouth
In the small and large intestine, peristalsis most directly results in what?
Movement of digestive tract contents
What are components of gastric juices?
Pepsin, mucus, hydrochloric acid
Digestive enzymes produced by the small intestine:
Peptidases, maltase, lactase
What is the process of contents of the digestive system being moved along by rhythmic contractions and relaxations of smooth muscle?
Peristalsis
The esophagus and trachea both connect to what?
Pharynx
The mouth and nasal passages lead to a hollow space at the back of the throat called the...
Pharynx.
What is the function of the liver?
Processes and stores nutrients, produces bile, important to metabolism
What is saliva?
Solution containing mucus, water, and salivary amylase, bicarbonate, and lysozyme secreted in the mouth
Which three parts of the human digestive tract contain mucus layers that produce digestive enzymes?
Stomach, mouth, small intestine
What is the function of the gallbladder?
Stores bile from the liver, sends it to the small intestine
What is the relationship between the epiglottis and glottis during swallowing?
The epiglottis covers the glottis
What is the serosa?
The thin, double-layered membrane that is the outermost layer
In diverticulitis, what happens to the abnormal pouches in the wall of the GI tract?
They become infected or inflamed
What are the enzymes involved in the digestion of proteins?
Trypsin, pepsin, and peptidase
What is the muscularis?
Two layers of smooth muscle
Diverticulosis
abnormal outpouchings in the intestinal wall of the colon
Hydrolyze
break down (a compound) by chemical reaction with water.
Chylomicrons
fat droplets covered in protein that diffuse into capillaries in small intestine
What are the steps of digestion?
ingestion, digestion, movement, absorption, elimination
What is the mucosa?
inner lining of digestive tract, glands release enzymes
What is the submucosa?
loose connective tissue that contains nerves, blood, and lymphatic vessels