Domain I: Principles of Dietetics: Principles of human anatomy, physiology, microbiology, and biochemistry Flashcards
Food in the oral cavity is chewed and mixed with ____ secreted by the parotid, submaxillary, and sublingual glands in the mouth
Saliva
Food then passes into the stomach via the esophagus through the cardiac valve into the ____, which is the upper portion of the stomach that holds the bulk of the food to be digested
Fundus
Most digestion in the stomach occurs in the ____ (lower) region
Pyloric
From the pyloric region, food is then forced into the ___ ____ through the pyloric valve of the stomach
Small intestine
Complete digestion occurs in the three parts of the small intestine, which are:
-Duodenum
-Jejunum
-Ileum
The hepatic duct from the ____ joins with the cystic duct from the ____
Liver; Gallbladder
____ is produced in the liver and stored in the gallbladder
Bile
Roles of the liver:
-Produces bile
-Produces glucose
-Stores glycogen
The ____ lies between the duodenum and the stomach
Pancreas
Undigested food and water pass through the ____ ____ into the large intestine/colon
Ileocecal valve
Chemical or enzymatic digestion occurs mainly in the ___ ___, but some in the stomach
Small intestine
In the stomach begins the process of proteolysis by protease ____ and _____
Pepcin and HCL
Limited continuation of starch hydrolysis occurs in the stomach due to the action of salivary ____
Amylase
In the stomach, the hormone _____ is released and stimulates gastric secretions and motility
Gastrin
The hormone cholecystokinin is released from the ____ when fat enters
Duodenum
Cholecystokinin contracts the gallbladder to release ____, and stimulates the pancreas
Bile
The hormone secretin is released from the ____
Duodenum
Secretin stimulates the flow of ____ ____ (bicarbonate) and water in the duodenum
Pancreatic juice
Secretin inhibits ____ ___ secretion
Gastric acid
Glucagon-like peptide (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), are released from the intestine in the presence of ____ and ____
Glucose and fat
Glucagon-like peptide (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) stimulate ____ synthesis and release
Insulin
_____ is the process of chewing that produces a bolus
Mastication
Rhythmic contractions of the esophagus force food into the stomach where it is mixed with gastric juice and reduced to ____, which is acidic
Chyme
Gastric emptying of a meal usually takes between ___ and ___ hours
2 and 6
Carbohydrate and protein-rich foods empty from the stomach at about the same rate, but high ____ foods and complex carbohydrates, especially ____ fibers, slow gastric emptying
Fat; soluble
Acidic chyme enters the _____, mixes with fluid and bicarbonate ions from the pancreas in order to neutralize the acid
Duodenum
Most digestion is completed by the middle of the ____ (nutrients absorbed include amino acids, fatty acids, glycerol, simple sugars, minerals, and vitamins)
Jejunum
_____ is the rhythmic movement of the small intestine
Peristalsis
_____ digestion occurs in the colon
Bacterial
The large intestine absorbs ____ and ____, as well as vitamins
Water and salts
The large intestine absorbs vitamins synthesized by bacteria, which are used by GI mucosal cells; these vitamins include:
-Vitamin K
-B12 (cobalamin)
-Thiamin (B1)
-Riboflavin (B2)
Colonic ____ is the process of anaerobic fermentation and absorption of end-products of carbohydrates, fiber, and amino acid breakdown
Salvage
Bacterial digestion converts malabsorbed carbohydrates and fiber into…
-Short-chain fatty acids
-Gases (H2, CO2, N, CH4)
Short-chain fatty acids like acetate, butyrate, propionate, and lactate stimulate ____ and ____ absorption in the colon and provide substrates for energy production
Water and sodium
The mouth can digest carbohydrates with the enzyme ____; fat and protein are also partially mechanically digested
Amylase
Amylase breaks starch into ____ and then ____
Dextrin; maltose
The stomach continues digestion of ___ and ___ through the action of amylase and mechanical digestion
Carbohydrates and fat
The stomach also continues with the digestion of protein through _____, which involves chemicals and enzymes
Proteolysis
____ is an enzyme that is created with the combination of pepsinogen and hydrochloric acid of the stomach
Pepsin
Pepsin acts on proteins to form ____ and ____
Proteose and peptones
Carbohydrates are digested in the small intestine with the help of pancreatic ____
Amylase
Intestinal ____ breaks down sucrose into glucose and fructose
Sucrase
Intestinal _____ breaks maltose down into glucose and glucose
Maltase
Intestinal ____ breaks lactose down into glucose and galactose
Lactase
What is the order of enzymes that are available for carbohydrate digestion?
- Maltase, sucrase
- Lactase
- Pancreatic amylase
Fat is digested in the small intestine through the action of…
-Bile salts (gallbladder)
-Lipase (pancreas)
-Cholesterol esterase (pancreas)
-Phospholipase (pancreas)
Bile salts from the gallbladder ____ fat
Emulsify
Lipase breaks down ____ into free fatty acids and glycerol
Triglycerides
Cholesterol esterase breaks down cholesterol into ____ ____
Cholesterol esters
Phospholipase breaks down phospholipids into ___ and ___ ___ ___
Lysolecithin; free fatty acids
Protein is broken down in the small intestine through the action of…
-Trypsin (pancreas)
-Chymotrypsin (pancreas)
-Carboxypeptidase (pancreas)
-Aminopeptidase (intestine)
-Dipeptidase (intestine)
Trypsin from the pancreas breaks protein, proteose, and peptones into ____
Polypeptides
Chymotrypsin from the pancreas breaks proteose, and peptone into ____ and ____
Polypeptides and dipeptides
The carboxypeptidase from the pancreas breaks down polypeptides into ____ and ____ ____
Dipeptides and amino acids
Aminopeptidase from the intestine breaks down polypeptides into ____ and ___ ___
Peptides and amino acids
Dipeptidase from the intestine breaks down dipeptides into ____ ____
Amino acids
Carbohydrates are absorbed in the small intestine and then metabolized in the liver by being converted to ____ or ____
Glucose or glycogen
Sources of glucose in the body:
-Dietary
-Liver glycogen
-Products of intermediary carbohydrate metabolism (conversion of lactic acid and pyruvic acid)
_____ amino acids are carbohydrate sources that also contain 68% amino acid
Glucogenic
Glucogenic amino acids yield glucose following _____
Deamination
_____ is the most glucogenic amino acid; it is catabolized to pyruvate or to Kreb’s cycle intermediates
Alanine
_____ is a carbohydrate source that contains 10% fat; it can be converted to glucose
Glycerol
Fatty acids and muscle glycogen do not contribute to the body’s supply of ____
Glucose
Uses of glucose:
-Energy
-Storage (glycogenesis in muscle and liver, lipogenesis)
-Small amount of converted into other carbohydrate compounds (ribose needed for form RNA, DNA)
Insulin is released by ____ cells of the pancreas
Beta
Roles of insulin:
-Increases cell permeability to glucose
-Fosters glycogenesis and lipogenesis
Glucagon is produced by ____ cells of the pancreas
Alpha
Glucagon induces _____, which converts glycogen to glucose
Glycogenolysis
Glucocorticoids break protein into glucose through the process of _____
Gluconeogenesis
Epinephrine is produced in the ____ ____
Adrenal medulla
Roles of epinephrine:
-Stimulates sympathetic nervous system
-Stimulates liver and muscle glycogenolysis (glycogen->glucose)
-Decreases release of insulin from pancreas during catabolic stress
Growth hormone and adrenocorticotropic hormone are insulin _____
Antagonists
Glucose in the cell is oxidized to produce…
-Energy
-Carbon dioxide
-Water
Glycolysis occurs in the ____ of the cell
Cytoplasm
The purpose of glycolysis is to produce ____ for the Kreb’s cycle by breaking down glucose, with or without oxygen, into pyruvate or lactose (depending on oxygen or not)
Pyruvate
