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HSES Exam 2 Study Guide
Terms in this set (54)
What functions do lipids (fat) serve in the body?
Provide energy (main source when at rest or light exercise)
Efficient storage of energy
Insulation and protection
Transport fat soluble vitamins
Satiety: slows rate of stomach emptying which enhances fullness
Flavor and mouthfeel
Health benefits (Omega 3 fatty acids)
What are the 4 types of fatty acids?
Trans fat (processed)
what are the 3 ways that the carbon chains can vary?
Number of carbons in the chain (4-24)
Extent to which chain is saturated with hydrogen
Saturated = no double bonds
Monounsaturated = 1 double bonds
Polyunsaturated = 2 or more double bonds
The shape of the chain (straight or bent)
Which 2 polyunsaturated fatty acids are essential?
Omega 3 and Omega 6
What are the health benefits of omega 3's, and what is the daily recommended intake?
1,000 - 2,000 mg
•Decreases blood clotting and the risk of heart attacks; too much can thin blood and result in hemorrhagic stroke
•Reduce blood pressure and triglycerides
•Anti-inflammatory; minimize plaque buildup in arteries
•May help lessen symptoms of depression
•May lower risk of some cancers
•Prevent macular degeneration
What is hydrogenation? Why is it done to fat found in foods?
•Process used to solidify an oil
•generally improves product taste and texture
•Lengthens shelf life
Explain how fat is digested once entering the small intestine (including enzymes and hormones involved)
• Small intestine is primary site of fat digestion (about 95%)
• CCK (hormone) is stimulates the release of bile and lecithin to help emulsify fat
• CCK stimulates pancreas to release pancreatic lipase
• Fat is broken down into monoglycerides and free fatty acids, and glycerol
Which pathway (receptor vs. scavenger) contributes to plaque formation and clogged
• Receptor pathway: preferred route as cholesterol safely enter the cell
• Scavenger pathway: contributes to plaque formation
What are the characteristics and functions of cholesterol in the body?
• Essential component of cell membrane
• Forms important hormones (estrogen, testosterone, vitamin D)
• Precursor to bile acids
• 40 - 60% of cholesterol in food is absorbed
• Body makes ample amount produced by liver found only in animal products)
What is atherosclerosis and arteries in which part of the body are most susceptible?
• Atherosclerosis is plaque build up in the arteries
• Common in heart and brain; kidney, legs, and feet are also susceptible
Define myocardial infarction and stroke?
• Myocardial infarction: heart attack; blood to the heart is blocked
• Stroke: blood flow to the brain is blocked
Why is it beneficial to have a high HDL level?
• High density lipoprotein (good cholesterol)
• Reduces plaque build up; picks up cholesterol from dying cells and LDL particles and transfers it back to liver
• Prevents LDL from oxidation
What should blood levels for overall cholesterol, LDL and HDL levels be?
• Overall cholesterol: 200 or lower
• LDL (bad cholesterol): 130 or lower
• HDL (good cholesterol): men = 40 or higher; women = 50 or higher
What are the daily recommendations (as grams per day) for saturated fat + trans fat?
• No more than 20 - 30 grams per day
• Should represent no more than 10% of daily calories
Why are antioxidants potentially helpful in preventing plaque build-up in arteries?
• Prevent LDL oxidation; LDL is more likely to be deposited into arteries when oxidized
What impact does exercise have on reducing risk of atherosclerosis?
• Larger and fewer LDL
• Increased LDL receptor synthesis
• Increases vascularity of heart
• Increases HDL
• Improves glucose tolerance and insulin sensitivity
• Aids in weight loss and lowering blood pressure
What makes protein chemically different that fat and CHO?
• Protein contains nitrogen in addition to C, H and O; carbs and fats only contain C, H, O
Define dipeptide, tripeptide, polypeptide and protein.
• Dipeptide = 2 amino acids
• Tripeptide = 3 amino acids
• Polypeptide = 3 to 100 amino acids
• Protein = 100 or more
How many total amino acids are there and how many are essential?
• 20 total amino acids
• 9 are essential
What one makes the structure of one amino acid different from another?
• Side groups (called R groups)
• Size, shape, electric charge, and side chains
What are the functions of proteins in our body?
• Provide energy
• Some are working molecules
What are the functions of protein from our diets?
• amino acids in the body make proteins
• After digesting amino acids the body will the use the amino acids as raw materials to make the proteins needed for the body
• If there is an excess of amino acids the body will metabolize in other ways
What are the two food groups (from the pyramid) that have the most protein per serving?
• Dairy and meats
What's the difference between complete vs. incomplete proteins?
• Complete: high quality protein; contains ample amount of all 9 essential amino acids and typical in animal food
• Incomplete: low quality protein; deficient or low in one or more essential amino acids and is typical in plant based food
What's a general example of protein complementation?
• Combining 2 lower quality protein foods to get all 9 essential amino acids
• Ex. eating vegetables and nuts
Describe protein digestion in the stomach and what are the end products?
• Starts in the stomach
• Hydrochloric acid (2 functions)
1. Starts protein digestion by providing the acidic environment needed to uncoil protein; opens up protein for attack by enzymes
2. Actives a protein digestion enzyme called pepsin which breaks down the proteins into smaller fragments
Describe protein digestion in the small intestine and what are the end products?
1. Pancreas and small intestine cells secrete various proteases that break down polypeptides to tripeptides, dipeptides and single amino acids
2. Enzymes on surface of SI cells break down remaining di- and tri-peptides to individual amino acids
What contributes to the amino acid pool
• Amino acids from diet
• Amino acids from cell breakdown
What are the 5 potential ways the body can use amino acids?
• Make proteins needed in the body
• Convert to neurotransmitters
• Convert into glucose
• Convert into fat
• Use for energy
• Deamination is the removal of the amino group, NH2, from amino acids
What happens to the nitrogen once it's removed?( specifically in the liver and kidney)
• Ammonia (NH3) travels to liver and becomes urea (NH2) and is released back into the blood
• Urea travels to the kidneys and most is excreted through urine
What is the general recommendation for % of total cals from protein (as a range) and what does that equate to for total grams (as a range on a 2,000 calorie diet)?
• 10 to 20% of total cals
• 50 to 100 grams
How many grams of protein are found in some common foods?
• Meats = 7 to 9 grams per ounce
• Dairy = 6 to 8 grams per serving
• Eggs = 6 to 8 grams per egg
• Vegetables = 2 grams per serving
• Beans = 5 to 20 grams per serving
• Grains = 3 to 5 grams per serving
Which scenarios result in increased protein requirements?
• Athletes and regular exercisers
• Growth periods
• Illness or injury recovery
• Low calorie diets
What are the potential nutrient deficiencies for vegetarians, especially vegans?
• Vitamin D
What are possible health benefits for adding soy foods to the diet and why are isoflavones beneficial?
• Lowers blood cholesterol 4 to 5%
• May reduce symptoms of low estrogen levels due to menopause
• May protect against breast cancer
• Higher quality source of protein
• Isoflavones can function like weak estrogen and can trick the body into thinking it has plenty of estrogen
Identify some of the protein based ingredients used in foods? What are they generally used for?
• MSG, protein hydrosylates, sodium caseinite, gelatin, wheat gluten protein, corn protein, isolated soy protein, whey protein isolate
What is whey protein and why is it the most popular protein supplement on the market?
• Whey is the liquid portion the separates out when cheese or cottage cheese is made
• Popular because its high in essential amino acids
• Especially high in amino acids that are a good fuel source for exercise
Explain the mechanism for how the body ends up in nutritional ketosis.
• A metabolic state in which the body is utilizing a higher percent of fat as energy to to lack of carbohydrate
• since no carbohydrate is available, the acetyl Coa's can't enter the Krebs cycle
• instead they convert into 1 of 3 ketone bodies (in the liver) then re-enter the bloodstream and can be used as energy
Explain the bottom line regarding high protein diets.
• For weight loss; high protein diets may result in quicker weight loss
• likely to be most effective for very obese and inactive population
• those who struggle with appetite control
• may have benefit for some when cycled
• Not sure what effect excessive intake of some food groups and little or no intake of other food groups will have on long-term health
• Weight loss is more complicated than blaming one macronutrient.
What are peristalsis and segmentation?
• Peristalsis: ring of contraction propelling material along the GI tract
• Segmentation: back and forth action that breaks down food
Identify the sphincters, their locations and functions.
• Cardiac or lower esophageal sphincter: prevents reflux of stomach content to cause heartburn and ulcers
• Pyloric sphincters: controls the amount of stomach content into the small intestine and prevents backup
• Sphincter of oddi: controls the amount of bile into the small intestine
• Ileocecal sphincter: prevents large intestine content (bacteria) from backing up into the small intestine
What are the functions of saliva?
• Contains enzymes that help breakdown carbohydrates
• Provides mucus to lubricate the food for easier swallowing
• Contains lysozymes to kill bacteria
What is the function of the epiglottis?
• Covers the passage to the airway to prevent food from entering the lungers
Name the accessory organs and their role in digestion.
• Liver, gallbladder and pancreas
• Bile acid is made in the liver then stored in the gallbladder
• Secreted in the small intestine when fat is present and starts the process of fat digestion
• Bicarbonate ions and enzymes from the pancreas neutralize acid from the stomach and further the digestion process
What are villi and microvilli?
• Villi: finger-like projections located on the folds of the small intestine
• Absorptive cells line the the villi surface and are covered with microvilli
• Glycocalyx is located on the microvilli
What is life span of intestinal absorptive cells?
• 3 to 6 days
What 4 hormones are involved in the digestion of fat, protein, and carbohydrates?
• Gastric inhibitory peptide
What nutrients are absorbed in the small intestine? The large intestine (colon)?
• Small intestine
1. Most minerals and water soluble vitamins (via portal circulation)
2. Monosaccharides and amino acids (via portal circulation)
3. Fat and fat soluble vitamins (via lymphatic circulation)
• Large intestine (colon)
1. Remaining water
What is the difference between portal circulation and lymphatic circulation? Which nutrients are absorbed in portal versus lymphatic?
• Portal circulation: villi capillaries to portal vein to liver
• most minerals, water soluble vitamins, monosaccharides and amino acids
• Lymphatic circulation: lymph vessel to thoracic duct to bloodstream and left subclavian vein
• fat and fat soluble vitamins
Define prebiotics and probiotics.
• Probiotics: consumption of beneficial bacteria in foods or supplements which improves the ratio of bacteria in the colon
• Prebiotics: consumption of foods that promote growth of good bacteria
What are the two kinds of bowel obstructions and what are examples of mechanical obstructions?
• Mechanical: a physical obstruction that blocks the GI tract
• Pseudo: no physical obstruction; bowels become paralyzed due to an problem of nerves that stimulate muscle contraction
What are symptoms and complications of bowel obstructions?
• Symptoms: abdominal distention, dehydration, nausea and vomiting, constipation
• Complications: blood supply is cut off which can cause intestinal cell death (necrosis)
What are the treatments for bowel obstructions?
• Rest the bowels (no intake of solids or liquids), then slowly reintroduce liquids or start tube feeding at a low volume
• If the obstruction is not resolved in roughly 5 days, receiving all nutrient forms through IV may be implemented
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