Nutrition Flashcards
Chronic disease
Progresses slowly or with little change and lasts a long time.
Acute disease
Develops quickly, produces sharp symptoms, and runs a short course.
acute = sharp
Digestion
The process by which food is broken down into absorbable units (nutrients).
Digestion = take apart
Absorption
The uptake of nutrients by the cells of the small intestine for transport into either the blood or the lymph.
absorb = suck in
Mastication
Chewing
Gastrointestinal (GI) tract
The digestive tract. The principle organs are the stomach and the intestines.
gastro = stomach intestinalis = intestine
Digestive system
All the organs and glands associated with the ingestion and digestion of food.
The four basic taste sensations:
Sweet, sour, bitter, salty
sometimes savory/umami is included
Lumen
The space within a vessel, such as the intestine.
Pharynx
The passageway leading from the nose and mouth to the larynx and esophagus, respectively.
Epiglottis
Cartilage in the throat that guards the entrance to the trachea and prevents food from entering it when a person swallows. Closes off the airway so that choking doesn’t occur when swallowing.
epi = upon (over) glottis = back of tounge
Esophagus
The food pipe; the conduit from the mouth to the stomach.
Sphincter
A circular muscle surrounding, and able to close, a body opening. Found at specific points along the GI tract and regulate the flow of food particles.
Band/binder
Esophageal sphincter
A sphincter muscle at the upper or lower end of the esophagus. The lower esophageal sphincter is also called the cardiac sphincter.
Stomach
A muscular, elastic, saclike portion of the digestive tract that grinds and churns swallowed food, mixing it with acid and enzymes to form chyme.
Pyloric sphincter
The circular muscle that separates the stomach from the small intestine and regulates the flow of partially digested food into the small intestine; also called the pylorus or pyloric valve.
pylorus = gatekeeper
Small intestine
A 10ft length of small-diameter intestine that is the major site of digestion of food and absorption of nutrients. Its segments are the duodenum, jejunum, and ileum.
Gallbladder
The organ that stores and concentrates bile. When it receives the signal that fat is present in the duodenum, the gallbladder concentrates and squirts bile through the bile duct into the duodenum.
Pancreas
A gland that secretes digestive enzymes and juices into the duodenum. (The pancreas also secretes hormones into the blood that help to maintain glucose homeostasis.)
Duodenum
The top portion of the small intestine (about “12 fingers’ breadth” long in ancient terminology)/
duodecim = 12
Jejunurn
The first 2/5 of the small intestine beyond the duodenum.
Ileum
The last segment of the small intestine.
Ileocecal valve
The sphincter separating the small and large intestines.
Large intestine or colon
The lower portion intestine that completes the digestive process. Its segments are the ascending colon, the transverse colon, the descending colon, and the sigmoid colon.
sigmoid = shaped like the letter S (Sigma in Greek)
Appendix
A narrow blind sac extending from the beginning of the colon that stores lymph cells.
Rectum
The muscular terminal part of the intestine, extending from the sigmoid colon to the anus.
Bolus
A portion; with respect to food, the amount swallowed at one time.
bolos = lump
Motility
The ability of the GI tract muscles to move.
Chyme
The semisolid mass of partly digested food expelled by the stomach into the duodenum.
chymos = juice
Peristalsis
Wavelike muscular contradictions of the GI tract that push its contents along.
peri = around stellein = wrap
Segmentation
A periodic squeezing or partitioning of the intestine at intervals along its length by its circular muscles.
Reflux
A backward flow.
re = back flux = flow
Enzymes
Facilitate the making and breaking of bonds in chemical reactions. The enzyme itself is a catalyst that remains unchanged.
Hormones
Act as chemical messengers, sometimes regulating enzyme action.
-ase
A word ending denoting an enzyme. The word beginning often identifies the compounds the enzyme works on.
Carbohydrase
An enzyme that hydrolyzes carbohydrates.
Lipase
An enzyme the hydrolyzes lipids (fats).
Protease
An enzyme that hydrolyzes proteins.
Digestive enzymes
Proteins found in digestive juices that act on food substances, causing them to break down into simpler compounds.
The enzymes involved in digestion facilitate a chemical reaction known as hydrolysis.
Hydrolysis
A chemical reaction in which a major reactant is split into two products, with the addition of a hydrogen atom (H) to one and a hydroxyl group (OH) to the other (from water, H2O). (The noun is hydrolysis, the verb is hydrolyze.)
The addition of water to break a molecule into smaller pieces. Breaks a disaccharide in two, with H added to one and OH to the other. Commonly occurs during digestion.
hydro = water lysis = breaking
The breakdown of food into nutrients requires secretions from five different organs:
- The salivary glands
- The stomach
- The pancreas
- The liver (via the gallbladder)
- The small intestine
Catalyst
A compound that facilitates chemical reactions without itself being changed in the process.
pH
The unit of measure expressing a substance’s acidity or alkalinity.
Glands
Cells or groups of cells that secrete materials for special uses in the body.
Exocrine glands
Secrete their materials “out” (into the digestive tract or onto the surface of the skin).
exo = outside krine = to separate
Endocrine glands
Secrete their materials “in” (into the blood).
endo = inside krine = to separate
Salivary glands
Exocrine glands that secrete saliva into the mouth.
Saliva
The secretion of the salivary glands. Its principal enzyme begins carbohydrate digestion.
Gastric glands
Exocrine glands in the stomach wall that secrete gastric juice into the stomach.
gastro = stomach
Gastric juice
The digestive secretion of the gastric glands of the stomach.
Hydrochloric acid
A acid composed of hydrogen and chloride atoms (HCI) that is normally produced by the gastric glands.
Mucus
A slippery substance secreted by the cells of the GI lining (and other body linings) that protects the cells from exposure to digestive juices )and other destructive agents). The lining of the GI tract with its coat of mucus is a mucous membrane.
Liver
The organ that manufactures bile. It is the first to receive the nutrients absorbed from the GI tract and prepares them for use by the body. It is the body’s major metabolic organ. Detoxifies substances that might cause harm and prepares waste products for excretion.
Stores about 1/3 of the body’s glycogen and releases glucose into the bloodstream as needed.
Bile
An emulsifier that prepares fats and oils for digestion; an exocrine secretion made by the liver, stored in the gallbladder, and released into the small intestine when needed.
It brings fats into suspension in water so that the enzymes can break them down into their component parts.
Emulsifier
A substance with both water-soluble and fat-soluble portions that promotes the mixing of oils and fats in a watery solution.
Pancreatic juice
The exocrine secretion of the pancreas, containing enzymes for the digestion of carbohydrate, fat, and protein as well as bicarbonate, a neutralizing agent. The juice flows from the pancreas into the small intestine through the pancreatic duct. (The pancreas also has an endocrine function, the secretion of insulin and other hormones.)
Bicarbonate
An alkaline compound with the formula HCO3 that is secreted from the pancreas as part of the pancreatic juice. (Bicarbonate is also produced in all cell fluids from the dissociation of carbonic acid to help maintain the body’s acid-base balance.)
Villi
Finger-like projections from the fold of the small intestine. (The singular is villus.)
Microvilli
Tiny, hairlike projections on each cell of every villus that can trap nutrient particles and transport them into the cells. (The singular is microvillus.)
Crypts
Tubular glands that lie between the intestinal villi and secrete intestinal juices into the small intestine.
Goblet cells
Cells of the GI tract (and lungs) that secrete mucus.
Water-soluble nutrients and small fat fragments that that pass through the cells of the villi enter the:
Blood
Fat-soluble nutrients that pass through the cells of the villi enter the:
Lymph
Capillaries
Small vessels that branch from an artery and connect arteries to veins. Exchange of oxygen, nutrients, and waste materials takes place across capillary walls.
The vascular (or blood circulatory) system
A closed system of vessels through which blood flows continuously, with the heart serving as the pump. As the blood circulates through this system, it picks up and delivers materials as needed.
Blood travels this route:
Heart > arteries > capillaries > veins > heart
Blood leaving the digestive system travels this route:
Heart > arteries > capillaries in intestines > to hepatic portal vein > to capillaries in liver > hepatic vein > heart
Aorta
The large, primary artery that conducts blood from the heart to the body’s smaller arteries.
Arteries
Vessels that carry blood from the heart to the tissues.
Veins
Vessels that carry blood to the heart.
Hepatic portal vein
The vein that collects blood from the GI tract and conducts it to the liver.
portal = gateway
Hepatic vein
The vein that collects blood from the liver and returns it to the heart.
hepatic = liver
Lactels
The lymphatic vessels of the intestine that take up nutrients and pass them to the lymph circulation.
Lymphatic system
A loosely organized system of vessels and ducts that convey fluids toward the heart. The GI part of the lymphatic system carries the products of fat digestion into the bloodstream. A one-way route for fluid from the tissue spaces to enter the blood.
Lymph
A clear yellowish fluid that is similar to blood except that it contains no red blood cells or platelets. Lymph from the GI tract transports fat and fat-soluble vitamins to the bloodstream via lymphatic vessels.
Thoracic duct
The main lymphatic vessel that collects lymph and drains into the left subclavian vein.
Subclavian
The vein that provides passage from the lymphatic system to the vascular system.
Flora
Bacteria in the intestines.
Prebiotics
Food components (such as fibers) that are not digested in the small intestine, but are used instead as food by bacteria to encourage their growth or activity.
Synbiotic
A mixture of probiotics and prebiotics.
Probiotics
Living microorganisms found in foods and dietary supplements that, when consumed in sufficient quantities, are beneficial to health.
pro = for bios = health
Two intricate and sensitive systems coordinate all the digestive and absorptive processes:
The hormonal (or endocrine) system and the nervous system.
Homeostasis
The maintenance of constant internal conditions (such as blood chemistry, temperature, and blood pressure) by the body’s control systems. A homeostatic system is constantly reacting to external forces to maintain limits set by the body’s needs.
homeo = the same stasis = staying
Hormones
Chemical messengers. Hormones are secreted by a variety of glands in response to altered conditions in the body. Each hormone travels to one or more specific target tissues or organs, where it elicits a specific response to maintain homeostasis.
Gastrin (a GI hormone)
A hormone secreted by the cells in the stomach wall. Target organ: the glands in the stomach. Response: secretion of gastric acid.
Secretin (a GI hormone)
A hormone produced by cells in the duodenum wall. Target organ: the pancreas. Response: secretion of bicarbonate-rich pancreatic juice.
Zymogen
The inactive precursor of an enzyme.
zym = concerning enzymes gen = to produce
Satiation / satiety
The feeling of satisfaction and fullness that occurs during a meal and halts eating. Determines how much time passes between meals.
sate = to fill
Satiation
The feeling of satisfaction and fullness that occurs during a meal and halts eating.
Carbohydrates
Compounds composed of carbon, oxygen, and hydrogen arranged as monosaccharides or multiples of monosaccharides. Most, but not all, carbohydrates have a ratio of one carbon molecule to one water molecule: (CH20)n.
4kcal/g
carbo = carbon (C) hydrate = with water (H20)
The four main types of atoms found in nutrients:
Hydrogen (H)
Oxygen (0)
Nitrogen (N)
Carbon (C)
Each atoms can form a certain number of chemical bonds with other atoms:
Hydrogen: 1
Oxygen: 2
Nitrogen: 3
Carbon: 4
Monosaccharides
Single sugars. Carbohydrates of the general formula CnH2n0n that typically form a single ring.
One of the sugars, sometimes called simple carbohydrates (along with disaccharides).
All three monosaccharides have the same formula, but their structures differ.
mono = one saccharide = sugar
Disaccharides
Sugars composed of pairs of monosaccharides, each containing a glucose paired with one of the three other monosaccharides.
One of the sugars, sometimes called simple carbohydrates (along with monosaccharides).
di = two
Polysaccharides
Large molecules composed of chains of monosaccharides.
Starches and fibers, sometimes called complex carbohydrates.
An intermediate string of 3-10 monosaccharides is an oligosaccharide.
poly = many oligo = few
The 6 most important sugars in nutrition:
Monosaccharides:
Glucose
Fructose
Galactose
Disaccharides:
Maltose (glucose + glucose)
Sucrose (glucose + fructose)
Lactose (glucose + galactose)
Glucose
A monosaccharide, sometimes known as blood sugar or dextrose.
ose = carbohydrate
Blue hexagon
Fructose
A monosaccharide, sometimes known as fruit sugar or levulose. The sweetest of the sugars. Found abundantly in fruit, honey, and saps. Same formula as glucose with a different structure.
fruct = fruit
Purple hexagon
Galactose
A monosaccharide, part of the disaccharide lactose. Occurs naturally as a single sugar in only a few foods.
Green hexagon
Carbs and all other energy nutrients are taken apart and put back together by:
Condensation and hydrolysis.
Condensation
A chemical reaction in which water is released as two reactants combine to form one larger product. Makes a disaccharide by linking two monosaccharides together.
Maltose
A disaccharide composed of two glucose units; sometimes known as malt sugar. Produced whenever starch breaks down, as in carb digestion and in fermentation.
Two blue hexagons
Sucrose
A disaccharide composed of glucose and fructose; commonly known as table sugar, beet sugar, or cane sugar. Also occurs in many fruits and some vegetables and grains.
sucro = sugar
A blue hexagon and a purple hexagon
Lactose
A disaccharide composed of glucose and galactose; commonly known as milk sugar.
lact = milk
A blue hexagon and a green hexagon
The three types of polysaccharides important in nutrition:
Glycogen
Starches
Fibers
Glycogen
An animal polysaccharide composed of glucose; manufactured and stored in the liver and muscles as a storage form of glucose. Not a significant food source of carbs and is not counted as a dietary carb in foods.
glyco = glucose gen = give rise to
Starches
Plant polysaccharides composed of glucose. The human body stores glucose as glycogen, but plants store glucose as starches. Grains are the richest food source of starch.
Fibers (dietary fibers)
In plant foods, the nonstarch polysaccharides that are not digested by human digestive enzymes, although some are digested by GI tract bacteria. Includes cellulose, hemicelluloses, pectins, gums, and mucilages as well as the nonpolysaccharides lignins, cutins, and tannins. Occur naturally in plants.
Soluble fibers and insoluble fibers.
Soluble fibers
Nonstarch polysaccharides that dissolve in water to form a gel (viscous), like pectin. They are also fermentable.
Viscous
A gel-like consistency.
Fermentable
The extent to which bacteria in the GI tract can break down fibers to fragments that the body can use.
Insoluble fibers
Nonstarch polysaccharides that do not dissolve in water, do not form gels, and are less readily fermented.
Promote bowel movements, alleviate constipation, and prevent diverticular disease.
Resistant starches
Starches that escape digestion and absorption in the small intestine of healthy people. Classified as dietary fibers. May support a healthy colon.
Phytic acid
A nonnutrient component of plant seeds; also called phytate. Occurs in the husks of grains, legumes, and seeds, and is capable of binding minerals such as zinc, iron, calcium, magnesium, and copper in insoluble complexes in the intestines, which the body excretes unused.
Amylase
A salivary enzyme that hydrolyzes amylose (a form of starch). Amylase is a form of carbohydrase.
Maltase
An enzyme that hydrolyzes maltose
Surcrase
An enzyme that hydrolyzes sucrose
Lactase
An enzyme that hydrolyzes lactose
Carbohydrase
An enzyme that hydrolyzes carbohydrates
Available carbohydrates
Starches and sugars - because the body can break them down and use them
Unavailable carbohydrates
Fibers - because the body cannot break them down and use them
Lactose intolerance
A condition that results from inability to digest the milk sugar lactose; characterized by bloating, gas, abdominal discomfort, and diarrhea. Not the same as milk allergy, which is caused by an immune reaction to the protein in milk.
Lactase deficiency
A lack of the enzyme required to digest the disaccharide lactose into its component monosaccharides (glucose and galactose).
Kefir
A fermented milk created by adding Lactobacillus acidophilus and other bacteria that break down lactose to glucose and galactose, producing a sweet, lactose-free product.
Gluconeogenesis
The making of glucose from a noncarbohydrate source (like protein)
gluco = glucose neo = new genesis = making
Protein-sparing action
The action of carbs (and fat) in providing energy that allows protein to be used for other purposes.
Ketone bodies
The metabolic products of the incomplete breakdown of fat when glucose is not available in the cells.
Ketosis
An undesirably high concentration of keytone bodies in the blood and urine.
Acid-base balance
The equilibrium in the body between acid and base concentrations.
Blood glucose homeostasis is regulated primarily by two hormones:
Insulin and glucagon
Insulin
Moves glucose from the blood into the cells.
A hormone secreted by special cells in the pancreas in response to (among other things) increased blood glucose concentration. The primary role of insulin is to control the transport of glucose from the bloodstream into the muscle and fat cells.
Glucagon
Brings glucose out of storage when necessary.
A hormone that is secreted by special cells in the pancreas in response to low blood glucose concentration and elicits release of glucose from liver glycogen stores.
Epinephrine
A hormone of the adrenal gland that modulates the stress response; formerly called adrenaline. The fight-or-flight hormone. When injected, epinephrine counteracts anaphylactic shock by opening the airways and maintaining heartbeat and blood pressure.
Two conditions from the failure of blood glucose regulation:
Diabetes or hypoglycemia.
Diabetes
A chronic disorder of carbohydrate metabolism, usually resulting from insufficient or ineffective insulin.
Fat
9 kcal/g
The WHO and the FAO suggest restricting consumption of added sugars to:
Less than 10% of total energy
The two major sources of energy in the diet:
Carbs and fats
A reasonable daily intake of high-fiber foods is:
Less than 40 grams
AMDR for carbs, fat, and protein:
Carbs: 45-65%
Fat: 20-35%
Protein: 10-35%
