Nutrition Quiz 2

Digestion

Process of breaking down large food molecules into nutrients that the body can absorb.

Absorption

Process of nutrient uptake from the gastrointestinal (GI) tract for transport through the circulatory or lymphatic system.

Primary organs

Mouth, esophagus, stomach, small intestine, large intestine

Accessory organs

Teeth, tongue, salivary glands, liver, gall bladder, pancrease

Mucosa

• Innermost layer of the digestive tract wall.

• Surround the lumen - hollow space through which food and fluids can pass

• Contains cells that secrete mucus - watery slippery fluid, that protects the GI tract lining and eases the flow of materials

Sphincters

Thickened regions of circular muscle that control the flow of contents at various points in the GI tract.

Mechanical Digestion

Physical breakdown of food as it passes through the intestinal tract. Teeth chew food.

Chemical Digestion

The breakdown of large nutrient molecules in food into smaller components, primarily by the action of enzymes. 

Bolus

mass of food that has been chewed and mixed with saliva and mucus. 

Pharynx

Section of the alimentary canal that connects the nasal cavity with the top of the esophagus. (Throat)

Enzyme

Protein that allows chemical reactions to occur at a rapid rate.

Some nutrients do not require digestion and are absorbed intact.

Water, cholesterol, minerals, and most vitamins.

Salivary Glands

Structures that produce saliva and secrete the fluid into the oral cavity.

Saliva

Watery fluid that contains mucus and a few enzymes.

Esophagus

Primary function: transfer bolus to the stomach

What happens when you swallow?

Epiglottis - flap of tough tissue that prevents food from entering trachea which can lead to choking. 

Peristalsis

Waves of muscular contractions that help move material through the intestine.

Upper Esophageal Sphincter (UES)

Circular muscle at the back of the throat that opens to allow a mass of food to enter the esophagus.

Lower Esophageal Sphincter (LES)

Circular muscle of the lower part of the esophagus that controls flow of material into the upper part of the stomach; also known as the gastroesophageal sphincter.

Pyloric Sphincter

• Located at the bottom of the stomach

• Controls flow of material into the upper part of the small intestine (Duodenum)

Gastric Juice

Watery solution of stomach secretions that includes mucus, hydrochloric acid, intrinsic factor, and digestive enzymes.

Gastrin

Hormone that stimulates stomach motility and gastric gland secretions.

Hormone

Chemical messenger that conveys information to target cells.

The pH scale is used to measure the concentration of hydrogen ions concentration of solutions.

• Neutral solutions have a pH of 7

• Acidic solutions have a pH lower than 7

• pH of chyme is around 2

• Alkaline (basic) solutions have a pH higher than 7

The Small Intestine

Primary site for mechanical and chemical digestion and nutrient absorption.

• Has three sections:

  • Duodenum - first segment

  • Jejunum - middle segment

  • Ileum - last segment

Liver

• Processes and stores many nutrients

• Produces cholesterol

• Produces Bile - greenish-yellow fluid needed for fat digestion and absorption

Gallbladder

• Stores and concentrates bile

• Secretes bile into the small intestine

Bioavailability

Amount of a nutrient that can be effectively digested, absorbed, and used by the body.

• Important when determining the true nutritional value of foods

Probiotics

Live microbes that promote good health for their human hosts; products that contain beneficial microbes.

Prebiotics

Substances in foods that promote the growth of beneficial microbes.

Fermented Foods

Foods made through controlled activity of live microbes to change their chemical composition.

Carbohydrates

Class of nutrients that is a major source of energy for the body.

• Plants are rich sources of carbohydrates

Monosaccharide

Simple sugar that is the basic molecule of carbohydrates.

The major dietary ones are:

• Glucose: Monosaccharide that is a primary fuel for muscles and other cells; “blood sugar.”

• Fructose: Monosaccharide in fruits, honey, and certain vegetables; “fruit sugar.”

• Galactose: Monosaccharide that is a component of lactose.

Disaccharide

Simple sugar composed of two monosaccharides.

The major dietary ones are:

• Maltose: Disaccharide composed of two glucose molecules; “malt sugar.”

• Sucrose: Disaccharide composed of a glucose and a fructose molecule: "table sugar.”

• Lactose: Disaccharide composed of a glucose and a galactose molecule; “milk sugar.”

High fructose corn syrup (HFCS)

Syrup obtained from the processing of corn.

• Fructose tastes much sweeter than glucose

Nutritive sweeteners

Substances that sweeten and contribute energy to foods.

Added sugars

Sugar added to foods during processing or preparation.

Alternative sweeteners

Substances that sweeten foods while providing few or no kilocalories. (Also known as artificial sweeteners)

Sugar alcohols

Alternative sweeteners used to replace sucrose in some sugar-free foods; sorbitol, xylitol, and mannitol. 

Nonnutritive sweeteners (also called “high-intesnity sweeteners”):

A group of compounds that are intensely sweet tasting compared to sugar.

Complex carbohydrates

Carbohydrates comprised of three or more monosaccharides bonded together.

Polysaccharides

Carbohydrates comprised of 10 or more monosaccharides bonded together. 

Oligosaccharides

Carbohydrates comprised of three to 10 monosaccharides bonded together. 

Starch

Storage of glucose (polysaccharide) in plants; composed of amylose and amylopectin.

Glycogen

Storage of glucose (polysaccharides) in animals. Highly branched storage polysaccharide in animals.

Dietary fiber

Nondigestible plant material; most types are polysaccharides.

Soluble fiber

Forms of dietary fiber that dissolve or swell in water; include pectins, gums, mucilages, and some hemicelluloses

Insoluble fiber

Forms of dietary fiber that generally do not dissolve in water; include cellulose, hemicelluloses, and lignin.

Insulin

Hormone secreted from the beta cells of the pancreas that contributes to a decrease in blood glucose levels.

Glucagon

Hormone secreted from the alpha cells of the pancreas that contributes to an increase in blood glucose levels.

Ketone bodies

Molecules formed from the metabolism of fat.

Ketosis

Adaptive metabolic state in which the body primarily uses fat for energy.

Type 1 diabetes

Autoimmune disease that results in destruction of the beta cells of the pancreas; as a result, insulin must be supplied to the affected person regularly through exogenous sources.

Type 2 diabetes

Most common type of diabetes; beta cells of the pancreas produce insulin, but the hormone’s target cells are insulin-resistant, leading to elevated blood glucose levels.

Gestational diabetes

Type of diabetes that can develop during pregnancy.

Hyperglycemia

Abnormally elevated blood glucose levels.

Hemoglobin A1c

Measures avengers blood glucose over several months.

Hyperinsulinemia

Condition in which the pancreas releases an excessive amount of insulin; over time, condition may contribute to the development of type 2 diabetes.

Syndrome

Group of signs and symptoms that occur together and indicate a specific health problem.