Flashcards in Human Digestion Deck (23)
What is the alimentary Canal?
The continuous tube extending from the mouth to the anus; also called gastrointestinal (GI tract or the "food tube".
List the seven components of the alimentary canal, starting with the mouth, and following the path of food through the body.
Mouth (oral cavity)
Contrast mechanical and chemical digestion in the mouth.
Mechanical: teeth break down food into smaller pieces.
Chemical: enzymes break down chemical bonds in the starch.
What is salivary amylase?
An enzyme contained in saliva that digest starch into maltose, a disaccharide.
What is peristalsis?
Wavelike contractions and relaxations of circular muscles in the oesophagi that push food into the stomach.
What is the stomach?
Mechanical and chemical digestion takes place here. Food enters from the oesophagus and is broken down by muscular contraction, enzymes and hydrochloric acid.
What are gastric juices?
Digestive liquid present in the stomach; composed of water, hydrochloric acid and enzymes.
What is pepsin?
Gastric (stomach) enzyme that digests protein into smaller polypeptides.
What is Chyme?
The partially digested contents of the stomach, in the form of a paste, that pass to the small intestine via the duodenum.
What is the pyloric sphincter
A muscular valve between the stomach and small intestine.
List four enzymes present in intestinal juice and their functions.
- maltase digests maltose (from starch)
lactase digest milk sugar (lactose)
sucrase digests cane sugar (sucrose)
lipase digests fat.
List four enzymes present in pancreatic juice and their functions.
Chymotrypsin digests protein.
trypsin digests protein.
amylase digests starch
pancreatic lipase digests fat.
What is the pancreas?
An organ located behind the stomach that secretes enzymes used in digestion as well as the hormones insulin and glucagon near the duodenum.
What is the Liver?
An organ next to the stomach that acts as the body's filter among several function it produces substances which break down fat, and other that affect sugar metabolism.
What is bile?
Breaks down large fat droplets into smaller droplets on which enzymes can act more efficiently. It is produced by the liver, stood in the gall bladder and relaxed through a duct into the small intestine.
What are the end products in the digestion of proteins, fats and carbohydrates?
Proteins: amino acids
Fats: fatty acides and glycerol
Carbohydrates: simple sugars (monosaccharides)
What are the functions of mucus in the stomach?
Protects stomach walls from the gastric juices.
lubricates stomach wall, which facilitates movement of food.
protects cells from abrasion by food.
What is the function of bicarbonate secreted by the pancreas?
Bicarbonate release into the small intestine neutralises the stomach acid and permits the pancreatic enzymes to function.
What is the small intestine?
Located between the stomach and the large intestine, where the majority of digestion and absorption takes place.
What is the Duodenum?
The first part of the small intestine; located right after the stomach. Near the pancreas.
What are the intestinal villi?
Numerous finger-like projections that line the small intestine and increase the surface are for absorbing nutrients.
What are Lacteal?
A lymph vessel inside each intestinal villus; faty acids and glycerol are absorbed into them and are carried into the lymph system.