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
The end product of aerobic glycolysis is ____
Pyruvate
The end product of anaerobic glycolysis is ____
Lactate
Glucose enters the cell, aided by insulin; it combines with phosphorus in the presence of magnesium to form _______, which proceeds pyruvic acid
Glucose-6-phosphate
Glucose-6-phosphate may lead to synthesis of ____
Glycogen
Liver glycogen releases ____ to blood to maintain normal blood sugar; this process requires glucose-6-phosphate
Glucose
____ cells do not have glucose-6-phosphate, so glycogen in those cells is only used for those cells
Muscle
Glucose-6-phosphate also proceeds through the ____ shunt (side-channeling of glucose)
Pentose
The pentose shunt does not require ____
ATP
The pentose shunt produces ____, which is part of RNA
Ribose
The pentose shunt also produces ____, which is essential for the synthesis of fatty acids because it contains niacin
NADPH
Pyruvic acid can proceed to form ___ ____, which is used for muscle contractions when energy needs exceed the supply of oxygen (only a small amount is produced)
Lactic acid
In the ____ Cycle, lactate is released from tissue, transported to the liver, and converted back to glucose as pyruvate
Cori
Most of pyruvic acid is converted to form ____ ____ (active acetate)
Acetyl CoA
Pyruvate is the main substrate for energy production in the ____ cycle
Kreb’s
What things are required for the Kreb’s Cycle?
-Thiamin (TDP)
-Niacin (NAD)
-Riboflavin (FAD)
-Pantothenic acid (CoA)
-Magnesium
-Lipoic acid
What are two other names for the Kreb’s Cycle?
-Tricarboxylic Acid Cycle (TCA cycle)
-Citric acid cycle
The Kreb’s Cycle takes place in the ____ of the cell
Mitochondria
Acetyl CoA comes from…
-Pyruvic acid (CHO)
-Oxidation of fatty acids
-Degradation of the carbon skeleton of certain amino acids
Acetyl CoA is the intermediate breakdown product of ___, ___ and ___
Carbohydrates, protein, and fat
Fatty acids enter the Krebs cycle as a ___-___ fragment
2-carbon
The Krebs cycle produces ____% of the body’s energy at ATP, in addition to CO2 and water
90
____ is the fuel needed to keep the Kreb’s cycle going
Carbohydrate
____ is the main carbohydrate fuel for the Krebs cycle and is formed from pyruvic acid and some amino acids
Oxaloacetate
Oxaloacetate reacts with acetyl CoA to form ___ ___ which starts the cycle
Citric acid
If there is not enough oxaloacetate coming in from carbohydrates to maintain the krebs cycle efficiently, acetyl CoA coming in from fat cannot be handled properly and is diverted for form _____ _____
Ketone bodies
Alpha ketoglutaric acid (produced from amino acids through gluconeogenesis) needs _____ for decarboxylation
Thiamin
Full oxidation of 1 molecule of glucose yields ____ ATP
38
Amino acids are broken down and transported to the capillaries, the portal bloodstream, and finally the ____
Tissues
_____ is needed for the transport of amino acids
Pyridoxine
What are three branched-chain amino acids (BCAAs)?
-Valine
-Leucine
-Isoleucine
Exercise releases ____ from muscle protein
Alanine
Alanine is transported to the liver, deaminated, and converted to ____
Glucose
Also during exercise, the oxidation of ____ (a BCAA) increases
Leucine
Tyrosine can be synthesized by _____
Phenylalanine
Cysteine can be synthesized from ____
Methionine
Nitrogen balance measures body _____; compares intake to output
Equilibrium
A nitrogen balance of ____ indicates maintenance/equilibrium
0
A positive nitrogen balance indicates a net ____ in body protein (commonly seen in infants, teens, pregnancy, and healing)
Gain
A negative nitrogen balance indicates ____ of body protein and/or inadequate intake
Erosion
Formula for determining nitrogen balance:
[(protein intake (g)/6.25)] - (UUN + 4)
___ ____ is a way to determine the quality of protein in food; it uses the nitrogen balance technique to determine the fraction of absorbed nitrogen retained for growth and maintenance
Biological value
Eggs have a biological value of ____, meaning that 100% of the nitrogen absorbed is retained
100
___ ___ ___ is another way of determining the quality of protein in food; it measures the amount of protein actually used
Net protein utilization
Formula for determining net protein utilization:
(Nitrogen intake - Nitrogen output (retained)) / (Nitrogen intake)
Another way of determining the quality of protein in food is…
Protein Digestibility Corrected Amino Acid Score (PDCAAS)
PDCAAS is the protein coefficient of _____; estimates the percentage of protein in each food category that is actually digested (animal 97%, plant proteins 70-90%)
Digestibility
Anabolism is another word for ____
Synthesis
The amount of ____ in a cell indicates the number of cells per organ, thus, helps determine stages of growth
DNA
DNA forms RNA on ____
Ribosomes
RNA forms a template (mold) which carries the plan to the ______
Cytoplasm
What B vitamin is involved in protein catabolism?
Pyridoxine (B6)
The first step in protein catabolism is ____, which involves splitting NH2 by hydrolysis in the liver
Deamination
NH2 is converted into ____ (NH3) which is toxic
Ammonia
Most of the ammonia is converted into ____ and excreted in the kidneys
Urea
Some ammonia is converted into ____, and some is used to make the nonessential amino acids through transamination
Purines
The remaining carbon chain is a ____ which can be oxidized for energy
Ketoacid
All proteins are oxidized to produce ____ ___ and ____
Carbon dioxide, water
What hormones are anabolic?
-Pituitary growth hormone
-Thyroid hormone
-Insulin
-Testosterone
What hormones are catabolic (stimulate gluconeogenesis)?
-Adrenal steroids
-Glucocorticoids
The end products of fat digestion:
-Monoglycerides
-Diglycerides
-Glycerol
-Fatty acids
Glycerol, short-chained fatty acids, and some phospholipids are absorbed directly into portal ____
Blood
Glycerol is ____-soluble
Water
Short-chain fatty acids have under _____ carbons
12
Monoglycerides, diglycerides, and long-chain fatty acids combine with the help of bile salts to form ____
Micelles
Micelles bind to protein to form lipoproteins like _____
Chylomicrons
Micelles can penetrate the intestinal mucosa, travel through the lymph, and into the thoracic duct, and into the ____
Blood
Some cholesterol is absorbed with ___ ___, while most is absorbed with ____ ____
Bile salts, cholesterol esterase
Cholesterol is converted to cholesterol esters and excreted by the liver as _____
Bile
____ is the synthesis and/or deposition of fat; promoted by insulin
Lipogenesis
_____ tissue is the most active site of lipogenesis
Adipose
Fatty acids + glycerol makes _____
Triglycerides
Lipogenesis requires ____ from the pentose shunt
NADPH
The liver ____ fat, but should not store it
Synthesizes
To prevent the accumulation of fat, lipotropic factors like ____ produce lipoproteins which transfer fatty acids out of the liver
Choline
_____ is a diet-derived lipoprotein made up of mostly triglyceride
Chylomicron
VLDL is about ____ triglyceride
Half
LDL is smaller and made up of mostly ____
Cholesterol
HDL is rich in _____
Protein
_____ causes oxidation of fat that forms acetyl CoA which then enters the Krebs Cycle
Lipolysis
What increases the rate of fat mobilization (lipolysis)?
-Glucocorticoid
-Thyroxine
-Epinephrine
-ACTH
What decreases the rate of fat mobilization (lipolysis)?
-Insulin
-Growth hormone
-Glucagon
Normal fat metabolism requires adequate ____ from complete fat oxidation
Carbohydrate
Without carbohydrate, ___ ___ form from the breakdown of fatty acids; they are made of acetoacetic acid, acetone, and beta-hydroxybutyric acid
Ketone bodies
When no carbohydrates are present, acetoacetic acid and beta-hydroxybutyric acid enter the blood and are taken to the peripheral tissues, are converted back to ____ ____, and oxidized as fuel
Acetyl CoA
Inadequate carbohydrate intake, due to ___ or ___ ____, results in incomplete fat oxidation and buildup of ketones
Starvation; uncontrolled diabetes
Ketones serve as fuel for the ____ and ____, but disturb acid/base balance
Muscles and brain
Most nutrients are absorbed through ____ transport (glucose, amino acids, Na, K, Mg, Ca, Fe)
Active
One example of active transport is the ____ pump, which works through uphill pumping from a lower to higher concentration gradient (it requires energy from ATP)
Sodium
Simple diffusion is used for the absorption of some ____ and ____; moves from higher to lower concentration such as the intestine to the blood to the lymph
Water and electrolytes
_____ diffusion is carrier facilitated and moves things from higher to lower concentration; used for the absorption of water-soluble nutrients
Passive
What things aid in the absorption of vitamin A?
-Bile salts
-Pancreatic lipase
-Fat
Vitamin D is hydroxylated in the ____, and then in the ____
Liver; kidney
Vitamin D requires ____ ____ and the acidity of chyme to be absorbed
Bile salts
Vitamin D accompanies the absorption of ____ and ____
Calcium, phosphorus
_____ aids in the absorption of riboflavin
Phosphorus
Vitamin B12 (cyanocobalamin) is absorbed in the ileum and is aided by stomach secretions like ____ and ____ ____
HCL and intrinsic factor
___ _____ aids in the absorption of non-heme iron
Hydrochloric acid
____ decreases iron absorption because it binds oxalates
Calcium
Absorption of folate is ____-dependent, as it cleaves polyglutamate to monoglutamate
Zinc
Folic acid in fortified foods and supplements is present as ____
Monoglutamate
The ____ is a key brain structure involved in the control of food and energy intake
Hypothalamus
Low levels of serotonin increase ____ intake
Carbohydrate
_____ is a hormone produced by fat cells in response to food intake
Leptin
Leptin induces _____ and suppresses appetite
Satiety
Leptin enhances ____ ____
Energy expenditure
____ is a hormone produced in the stomach and intestine to stimulate appetite and growth hormone secretion from the pituitary
Ghrelin
Ghrelin ____ fat utilization in adipose
Decreases
Low leptin and high ghrelin promote excess ___ ___
Food intake
____ determinants of health are conditions in the places where people live, learn, work, and play that affect a wide range of health risks and outcomes
Social
Examples of social determinants of health:
-Economic stability
-Education
-Social and community context
-Access to healthy food and safe neighborhoods
-Access to health care
A ____ is the sum of the organism’s genetic material
Genome
Nutritional ____ focuses on diet and lifestyle-related disorders resulting from the interactions between the genome and environmental factors such as nutrients, toxins, physical activities, sleep, and stress
Genomics
Nutritional genomics provides a greater understanding of how to use nutrition therapy to promote ____ and prevent ____
Health; disease
