Chapter 26 - Gastrointestinal System

The digestive system

system of organs that are responsible for getting food into and out of the body and for making use of food to keep the body healthy.

Bile

A substance produced by the liver that breaks up fat particles.

Peristalsis

Involuntary waves of muscle contraction that keep food moving along in one direction through the digestive system.

Six main organs of the digestive system

mouth

Six accessory organs of the digestive system

teeth

Excretion

Process of removing wastes from the body.

Mouth

the beginning of the alimentary tract where the teeth tongue

Mastication

chewing occurs as the teeth break up the food pieces ito smaller particles

Monosaccharide

simplest form of carbohydrate (glucose

Bolus

A term used to describe food after it has been chewed and mixed with saliva

Pharynx

Also called the throat. Consists of these three areas; naso

Trachea

also called the windpipe

Ptyalin

a digestive enzyme of the saliva that turns starch into maltose (salivary amylase)

Esophagus

A muscular tube that connects the mouth to the stomach. about 10 inches long

Lower esophageal sphincter (LES)

also called the cardiac sphincter

Stomach

consists of three parts; the funds

Chyme

the liquid that food turns into before it passes into the small intestine. Consistency of a thick soupy liquid.

Pepsinogen

precursor to pepsin

Pepsin

digestive enzyme needed to break down food proteins

Small intestine

consists of three parts; the duodenum

Duodenum

is the first part of the small intestine

Lipid

Energy-rich organic compounds

Emulsification

Physical process of breaking up large fat globules into smaller globules

Protease

enzyme that begins protein breakdown

Pancreas

An organ of the digestive system that produces a fluid that neutralizes stomach acid and chemicals that help finish digestion. Sends out three enzymes; trypsin (a protease)

Villi and Microvilli

Tiny finger-shaped structures that cover the inner surface of the small intestine and provide a large surface area through which digested food is absorbed

The large intestine

or colon is divided into seven sections; cecum

Waste

material or residue that is not absorbed

Gastroesophageal reflux disease (GERD)

commonly called heartburn or acid reflux

Nausea

precedes vomiting and is a feeling of awareness that something is stimulating the vomit center and that vomiting is going to occur

Vomiting

or emesis is produced by involuntary contraction of the abdominal muscles when the fundus and LES are relaxed

Causes of nausea and vomiting

Migraines

Ulcers

An area of inflammation that opens out to a skin or mucous surface; ulcers that heal within 12 weeks are usually classified as acute

Peptic Ulcer

is a sore that forms in the lining of the stomach or the duodenum

Gastric mucosa

Produces gastrin which stimulates digestive enzymes

Ulcer Therapy

Antibiotics and either proton pump inhibitors or an H2 blocker to suppress acid production

Constipation

is a GI condition characterized by hard

Causes of constipation

Diets high in fat and low in fiber

(such as MS

stoke

Bulk forming laxatives

which work in the intestine by absorbing water to make the stool softer. Considered the most common and safest type of laxative

Emollient laxatives

which work by stopping the colon from absorbing fecal water

Evacuant laxatives

used for bowel cleansing before medical exams

Fecal softeners/surfactants

which work in the intestines and help mix fat and water to soften stool

Hyperosmotic laxatives

which cause colon fluid retention and thereby increases peristalsis

Saline laxatives

which draws water into the colon

Stimulants/irritants

which work by causing rhythmic intestinal contractions

Dietary reference intakes (DRI)

nutritional guidelines that include both recommended intakes and tolerable upper intake levels

Macronutrients

are nutrients that the body requires in relatively large quantities

Kilocalories (kcal)

unit of measurement for food energy

Carbohydrates

classified as simple or complex

Acceptable macronutrient distribution range (AMDR)

the range of intake levels that provide adequate amount of a nutrient and are associated with a reduced risk of disease

The main functions of body fat are to

help to provide lubrication

Low-density lipoprotein (LDL)

bad cholesterol

high-density lipoprotein (HDL)

good cholesterol

Hydrogenated fats

polyunsaturated vegetable oils to which hydrogen has been added commercially to make them solid at room temperature.

Complete or essential proteins

have the essential amino acids necessary to build other proteins

Incomplete protein

are missing one or more of the amino acids needed to build other proteins

micronutrients

are nutrients that the body requires only small quantities

Fat-soluble vitamins

A

Vitamin A

retinol

Carotenosis

the yellowness or orangness of skin from to much Beta-carotene

Vitamin D

Produced in the skin from exposure to sunlight. Found in fatty fish

Fortified

with an added nutrient for enrichment

Vitamin E

is found in wheat germ oil

Malabsorpation

an abnormality in digestion that causes nutrients to be absorbed poorly or not at all

Vitamin K

phytonadione is found primarily in dark-green leafy vegetables

Water-soluble vitamins

for the most part are carried in the bloodstream and excreted in the urine. Include B1

Vitamin B1

thiamine can be found in fortified bread and cereals

Hypermetabolic

metabolizing at an increased rate

Vitamin B2

Riboflavin is found in liver

Vitamin B3

Niacin is found in lean meats

Vitamin B5

Pantothenic acid can be found in beef

Vitamin B6

Pyridoxine is found in fortified cereals

Vitamin B9

Folic acid is found in barley

Vitamin B12

Cyanocobalmin is found in mollusks

Vitamin C

Ascorbic acid is found in citrus fruit

Minerals

are inorganic compounds that are much smaller than vitamins and occur in much simpler forms. Elements of the earth needed in the diet

Major minerals

are needed in the bodying larger quantities

Minor minerals

are needed in amounts of less than 100mg per day; iron

Antioxidant

molecule that sows or prevents the oxidation of other molecules

Exogenous

from outside the organism

Calcium

Is needed for bone muscle

Iron

Maintains oxygen levels in blood

Magnesium

Aids in energy metabolism

Potassium

Maintains proper muscle memory function

Selenium

Supports immune system and thyroid

Sodium

Regulates body fluids

Zinc

Aids in the healing process

Water

Makes up 60 percent of an adults body weight. It forms a major portion of every tissue and provides the medium in which most of the body's activities are conducted. It also facilitates many of the metabolic reactions that occur in the body and helps transport vital materials to the cells. Helps glycogen to be transported into muscle cells.

Glycogen

Often referred to as muscle fuel

USDA - MyPyramid guidelines

Make healthy food choices

Food allergies

90 percent of reactions are caused by one of the following eight foods; milk

Food intolerance

cause the same symptoms as food allergies but without involving the immune system.