Chapter 4 Terms and Tables

Vomiting Danger Signs

1. Lasts longer than a few hours (children under 6 years of age) 2.) Lasts longer than a day (people over 6 years of age) 3) Is accompanied by: Blood in vomit (looks like coffee grounds) Signs of dehydration Diarrhea Fever Weakness Headache or stiff neck Sever abdominal pain Confusion or decreased alertness

Mucosa

Innermost layer of the GI tract.

Digestion

Is the process of breaking down large food molecules into nutrients that the body can use.

Pharynx

Is the section of the alimentary canal that connects the nasal cavity with the top of the esophagus.

Absorption

Is the uptake and remval of nutrients from the digestive tract.

Bolus

Mass of food that has been chewed moistened, mixed with saliva, and swallowed.

goblet cells

Mucus secreting cell inside the mucosa of the large intestine

Simple Diffusion

Occurs when the concentration of a particular nutrient is higher in the lumen of the small intestine than in an enterocyte.

Possible Health Benefits of PROBIOTICS (Live Bacteria)

Prevention and treatment of diarrhea, Prevention and treatment of inflammatory bowel disease (IBD), Improved blood fat levels, Protection against ulcers, Prevention and treatment of lactose intolerance

G Cells

Secrete gastrin, a hormone that enters the blood stream and stimulates stomach motility and the secretory activity of the gastric glands.

What types of nutrients are absorbed into the heptic portal vein and eventually into the liver before they enter the general circulation?

Water-soluble vitamins

cecum

Where unabosrbed water and digested remains of chyme go.

The main function of _____ is to emulsify fat, thus assisting in digestion.

bile

Lysozyme

can destroy some bacteria that are in food or the mouth.

mucous cells

cells that secrete mucus.

gastroesophageal reflux disease (GERD)

chronic condition characterized by frequent heartburn that can damage the esophagus

Lingual lipase

enzyme is inactive until it reaches the stomach.

______ is a process of diffusion but requires no energy

facilitated diffusion

Digestive System

has two major components, GI tract and accessory organs

constipation

infrequent bowel movements and feces that are difficult to eliminate

Chemical Digestion

is the breakdown of large nutrient molecules in food into smaller components, primarily by the action of stomach acid and various enzymes.

probiotics

live microorganisms that promote good health for their human hosts

jejunum

middle segment of the small intestine

stomach

muscular sac that stores and mixes food

Upper Esophageal Sphincter (UES)

opens when the bolus is swallowed, allowing the mass of food to enter the esophagus.

heartburn

pain generally felt in the upper chest that results from the passage of acidic contents from the stomach into the esophagus

segmentation

regular contractions of the circular intestinal muscles followed by the muscular relaxations that mix chyme within a short portion of the small intestine

alkaine

solutions with pH values higher than 7

acidic

solutions with pH values lower than 7

peptic ulcer

sore that occurs in the linging of the stomach or upper small intestine.

hemorrhoids

swollen veins in the anal canal

microvilli

tiny hairlike projections that form the brush border of an enterocyte

hepatic portal vein

vein that transports absorbed nutrients to the liver.

lacteal

vessel of the lymphatic system

Chyme

A semi-liquid mass from mixed food and gastric juices

Mucus

A watery, slippery fluid.

Panceras

An accessory organ of the digestive tract that produces and secretes many of the enzymes that break down carbohydrates, protein, and fat in the GI tract. Additionally, the pancreas secretes biocarbonate ions (HCO3-)

Hormones

Chemical messengers that convey information to cells.

Anosmia

Complete inability to detect odors

Epiglottis

Flap of tough tissue that prevents the food from entering the larynx and trachea.

Hormone: Secretin

Primarily Released From: Small Intestine Responds to: Acidic chyme entering the duodenum and first part of the jejunum Key Actions: Stimulates the release of a biocarbonate-rich solution from the liver and pancreas

Lingual lipase and salivary amylase are to components of the liquid called _________ which is produced by glands in the mouth.

Saliva

Salivary glads

Secrets saliva as a person chews

Sucrase, maltase, lactase

Small intestine, breaks down certain sugars into simpler sugars

Intestinal lipase

Small intestine, breaks down fats into smaller components.

Peptidase

Small intestine, breaks down partially digested protiens

What two distinct tissues make up the muscle layer?

The circular and the longitudinal muscles.

enterocytes

absorptive cells that form the outer layer of a villus

pepsin

active enzyme that begins the enzmatic digestion of proteins

external anal sphincter

allows feces to be expelled and is under voluntary control (defecation)

gastric juice

collection of stomach secretions that includes mucus, hydrochloric acid, intrinsic factor, and digestive enzymes

diverticulitis

condition characterized by INFLAMED diverticula

diverticulosis

condition characterized by the presence of diverticula

inflammatory bowel disease

condition that is characterized by chronic inflammation of the GI tract

duodenum

first segment of the small intestine

bile

fluid that is produced in the liver and stored in the gall bladder until it is needed for fat digestion and absorption

prebiotics

food components that beneficial bacteria in the large intestine use for fuel

secretin

hormone secreted by the duodenum and the first part of the jejunum that stimulates the pancreas and liver to release a biocarbonate-rich solution into the small intestine.

cholecystokinin (CKK)

hormone secreted by the mucosa of the small intestine that stimulates the gallbladder to contract and the pancreas to release pancreatic juice into the small intestine.

Salivary amylase

initiates chemical digestion in the mouth. Amylase begins the breakdown of starch.

rectum

last section of the large intestine

ileum

last segment of the small intestine

Esophagus

musuclar tube that extends about 10 inches from the pharynx to the upper portion of the stomach

microflora

population of several kinds of bacteria

Enzyme

protein that speeds up the rate of a chemical reaction without being altered in the process.

ileocecal sphincter

region of the ileum that controls the rate of emptying undigested material into the large intestine

Chief Cells

secrete gastric lipase and some chemically inactive digestive enzymes, particulaly pepsinogen.

diverticula

tiny pouches that form in the wall of the colon

ageusia

total loss of the ability to taste substances.

ulcerative colitis (UC)

type of IBD that causes ulcers to form in the mucosa of the colon and rectum

Saliva

A watery fluid that contains mucus and a few enzymes, including lysozyme, salivary amylase, and lingual liapse. Lubricates food making it easier and more comfortable to swallow.

Possible Health Benefits of PREBIOTICS (often Fiber Rich Foods)

Alleviate constipation, Improved immune function, Protection against colon cancer, Alleviate allergy symptoms, Prevention of obesity.

Lower Esophageal Sphincter (LES)

Also known as the gastroesophageal sphincter or cardiac sphincter, is located at the bottom of the esophagus and controls the flow both in and out of the stomach. Normally, the LES is closed, preventing the backflow of acidic stomach contents into the esophagus. Heartburn ("acid reflux") occurs when the LES fails to close properly.

Digestive Tract

Also known as the gastrointestinal tract (GI tract), alimentary canal, or gut.

Hypogeusia

Diminished ability to taste substances

Dumping Syndrome

Disorder that occurs when chyme flows too rapidly into the small intestine

Osmosis

Each day, about 7.6 to 8.5 quarts (1824 to 2040 mL) of water from ingested foods and beverages, as well as the watery secretions of the intestinal cells, enter the lumen of the GI tract. Water moves freely across the cell membranes of enterocytes, because a concentration gradient is created by the absorption of water-soluble nutrients, such as sugars and minerals. A healthy body absorbs most of the water that enters the GI tract.

Facilitated diffusion

Enterocytes absorb some nutrients by facilitated diffusion, a process that also does not require energy. Although the nutrient moves down in its concentration gradient, it stills needs to be carried by a special transport protein within the membrane of the enterocyte. Transport proteins are specific for the type of nutrient they are responsible for carrying. Absorption of the simple sugar fructse occurs by facilitated diffusion.

Factors that Contribute to or Worsen Heartburn

Having excess body fat, especially around the waistline Drinking alchohol, coffee, carbonated beverages, and citrus juices Overeating Eating chocolate, peppermint, and greasy or spicy foods Eating foods that contain tomatoes or vinegar Smoking

Endocytosis

In a few instances, a segment of an absorptive cell's plasma membrane surrounds and "swallows" relatively large substances, such as entire protien molecules. This process enables an infant's intestinal tract to absorb whole protiens in human milk that provide immune benefits. Endocytosis, however, is not a common way for nutrients to enter enterocytes.

Lumen

In the digestive tract, hollow space which food and fluids pass.

Hormone: Cholecystokinin

Primarily Released From: Small intestine Responds to: Fat and breakdown products of proteins (peptides) entering the small intestine Key Actions: Stimulates release of bile from the gallbladder into the small intestine. Stimulates the release of pancreatic enzymes, decreases stomach secretions, and slows stomach motility

Hormone: GASTRIN

Primarily released from: Stomach Responds to: Food Entering Stomach Key Actions: Triggers parietal cells to release HCI and the chief cells to release pepsinogen. Stimulates stomach and small intestinal motility.

Active transport

Some nutrients move from the lumen of th intestine qand into an enterocyte against the concentration gradient; that is, the concentration of the nutrient is higher inside the absorptive cell than in the lumen Absorption of these nutrients requires both a unique transport proteien and energy. Enterocytes rely on active transport to absorb glucose and amino acids.

Carboxypeptidase

Source: Pancreas, Action: Breaks down certain partially digested protiens

Nuclease

Source: Pancreas, Action: Digests DNA and RNA into nucleotides

pancreatic amylase

Source: Pancreas, Action: Digests Starch

Pancreatic lipase

Source: Pancreas, Action: Digests fat into smaller components

Trypsin, chymotrypsin

Source: Pancreas, Action: Partially digest proteins

What food does not cause choking in small children?

Spaghetti

Amylase i the enzyme needed to digest _____

Starch

Oral cavity

Start of digestion, the mouth.

Pyloric Sphincter

Surrounds pylorus and regulates flow of chyme into the small intestinte

Parietal cells

Synthesize and release intrinsic factor, the substance that is necessary for absorbing vitamin B-12

Taste Buds

Taste buds have specialized cells that help distinguish five basic tastes: sweet, sour, salty, bitter and the savory or umami taste.

Peristalsis

The act of swallowing signals the GI tract that food is being eaten and stimulates peristalsis, waves of muscular contractions that help move material through most of the digestive tract.

Disorders of taste and smell

The sense of smell (olfaction) contributes to the ability to taste food. As food is chewed, it releases chemicals that become airborne and stimulate the olfactory region of the nasal passages. This region signals the two olfactory bulbs, specialized structures in the brain that are essential for being able to sense odors. The brain combines information about the smell of foods with taste sensations from the mouth to identify the food's flavors. When a person has an upper respitory tract infection and the inside of the nose is congested, his or her favorite foods may seem tasteless and unappealing, because the olfactory region is unable to function properly.

Sphincter

Thickened regions of circular muscle that function like vales to control the flow of contents at various points in the GI tract. Wen an intestinal sphincter relaxes, the passageway opens and the contents of the GI tract flow through it. When a sphincter contracts, it closes the passageway and restricts the flow at that point in the digestive tract.

How is the stomach lining protected by the stomachs acidic enviroment

a mucus lining

Mechanical Digestion

refers to physical treatments that food undergoes while it is in the intestinal tract, such as being chewed into smaller pieces and mixed with various secretions. Mechanical digestion does not change the chemical composition of the food, but it facilitates chemical digestion.

villi

tiny, fingerlike projections of the small intestinal mucosa that are involved in digestion and nutrient absorption

Crohns Disease

type of IBD; the bodys immune system cells attack the normal intestinal cells, damaging parts of the intestines.