Principles of Nutrition Chapter 3

food in the trachea

Choking is caused by:

Somatostatin

Decreases motility of stomach/intestines Inhibits release of gastrin

Cholecystokinin is released in response to fat or protein in the small intestine. In addition to its role in fat emulsification and digestion, cholecystokinin slows GI tract motility. Slowing the digestive process helps maintain a pace that allows all reactions to reach completion. Hormonal and nervous mechanisms like these account for much of the body's ability to adapt to changing conditions.

Fat and protein take longer to digest than carbs do. When fat or protein is present, intestinal motility slows to allow time for its digestion. How does the intestine know when to slow down?

The stomach normally maintains a pH between 1.5 and 1.7. How does it stay that way?

Food entering the stomach stimulates cells in the stomach wall to release the hormone gastrin. Gastrin, in turn, stimulates the stomach glands to secrete the components of hydrochloric acid. When pH 1.5 is reached, the acid itself turns off the gastrin-producing cells; they stop releasing gastrin, and the glands stop producing hydrochloric acid. Thus, the system adjusts itself.

target organ: small intestine/ secretion: bile/ action: bile emulsifies fat so that enzymes can have access to break it down

Gallbladder: Target Organ, secretion, and action

Target organ: stomach/ Secretion: Gastric juice/ Action: fluid mixes with bolus; hydrochloric acid uncoils proteins; enzymes break down proteins; mucus protects stomach cells

Gastric glands: Target Organ, secretion, and action

the backflow of stomach acid into the esophagus, causing damage to the cells of the esophagus and the sensation of heartburn

Gastroesophageal reflux and indigestion

foods eaten together can enhance each others use by the body

How does food combining affect the digestive system?

hydrochloric acid secreted into the stomach to maintain an acidic pH

How does the body respond to a release of gastrin?

Bile secreted into the duodenum to emulsify fats Bicarbonate- and enzyme-rich juices secreted into the small intestine to maintain a slightly alkaline pH, digest fats and proteins, and slow GI tract motility

How does the body respond to the release of cholecytokinin?

Bicarbonate-rich juices secreted into the small intestine to maintain a slightly alkaline pH

How does the body respond to the release of secretin?

target organ: gallbladder/ secretion: bile/ action: bile is stored until needed

Liver: Target Organ, secretion, and action

target organ: small intestine/ secretion: pancreatic juice/ action: bicarbonate neutralizes acidic gastric juices; pancreatic enzymes break down carbohydrates, fats, and proteins

Pancreas:Target Organ, secretion, and action

Enzyme activity changes proportionately in response to the amounts of carbohydrate, fat, and protein in the diet. If a person has been eating mostly carbohydrates, the pancreas makes and secretes mostly carbohydrases; if the per- son's diet has been high in fat, the pancreas produces more lipases; and so forth. Hormones from the GI tract, secreted in response to meals, keep the pancreas in- formed as to its digestive tasks. The day or two lag between the time a person's diet changes dramatically and the time digestion of the new diet becomes efficient explains why dietary changes can "upset digestion" and should be made gradually.

Pancreatic secretions contain a mixture of enzymes to digest carbohydrate, fat, and protein. How does the pancreas know how much of each type of enzyme to provide?

Motlin

Response to bile and pancreatic secretions Promotes gastric emptying

GIP (Gastric Inhibitory peptide)/ GLP-1 (glucagon like peptide)

Response to glucose and fat Insulin release Maintains BG from rising following meal

Target organ: mouth/ Secretion: Saliva/ Action: fluid eases swallowing; salivary enzyme breaks down some carbohydrate

Salivary Gland: Target Organ, secretion, and action

As the chyme enters the small intestine, the pancreas adds bicarbonate to it so that the intestinal contents always remain at a slightly alkaline pH. How does the pancreas know how much to add?

The presence of chyme stimulates the cells of the duodenual wall to release the hormone secretin into the blood. When secretin reaches the pancreas, it stimulates the pancreas to release its bicarbonate-rich juices. Thus, whenever the duodenum signals that acidic chyme is present, the pancreas responds by sending bicarbonate to neutralize it. When the need has been met, the cells of the duodenal wall are no longer stimulated to release secretin, the hormone no longer flows through the blood, and the pancreas no longer receives the message and stops sending pancreatic juice. Nerves also regulate pancreatic secretions.

pH, peristalsis, diet, and other microbes

What affects the microbes in the GI tract?

grains, fruits, and milk

What are considered carbohydrates?

chyme and fullness or abdominal or lumen distention.

What are muscle receptors in the gut are sensitive to?

ascending colon, transverse colon, descending colon, and sigmoid colon

What are the parts of the large intestine

duodenum jejunum, and ileum

What are the three segments of the small intestine?

segmentation and peristalsis

What are the two layers of muscle in the GI tract that produce action?

simple diffusion, facilitated diffusion, active diffusion

What are the types of absorption techniques used in the small intestine?

IBS, colitis, and celiac disease. Treatment begins with rehydration

What are three digestive conditions where diarrhea is a common symptom

chylomicrons

What carries fats through the body because they are insoluble in water?

Bacterial infection Anti-inflammatory drugs Excessive gastric acid secretion

What causes and ulcer

fat or protein in the small intestine

What does cholecystokinin respond to

food in the stomach

What does gastrin respond to?

stomach glands

What does gastrin stimulate

acidic chyme in the small intestine

What does secretion respond to?

stress, drugs, and illness

What factors interfere with GI tract contractions?

a result of lifestyle, some medications cause constipation, fiber, fluid, and physical activity help prevent constipation

What is constipation

fermentation by bacteria occurs in the large intestine; gas production is mainly caused by sugars, fiber, and starch

What is the cause of intestinal gas

mouth,esophagus, stomach, small intestine, large intestine, rectum, and anus

What is the oder of body parts that food passes through

strong acidity prevents bacterial growth and kills most bacteria that enter the body with food

What is the purpose of the stomach's pH

Signal nerves embedded in the gut. contract/ relax muscles. increase or decrease fluid secretions. change blood flow

What is the role of neurotransmitters in GI movement?

liquefy chyme with gastric juices and force chyme downward

What is the role of the stomach muscles

an adaptive body mechanism that can often result in dehydration

What is vomiting and a common side affect

circular, longitudinal, and diagonal muscles

What muscles make up the stomach?

salivary gland, stomach, pancreas, liver (via gallbladder), and the small intestine

What organ aid in the breakdown of food into nutrients through secretions

• Take medicine as prescribed by your physician. • Avoid coffee and caffeine- and alcohol-containing beverages. • Avoid foods that aggravate your ulcer. • Minimize aspirin, ibuprofen, and naproxen use. • Refrain from smoking cigarettes.

What should be done to prevent an ulcer?

Eat slowly. Chew thoroughly. Relax while eating

What should be done to prevent belching?

cut food into small pieces, chew thoroughly before swallowing, don't talk or laugh with food in your mouth, and don't eat when breathing hard

What should be done to prevent choking?

Eat a high-fiber diet. Drink plenty of fluids. Exercise regularly. Respond promptly to the urge to defecate.

What should be done to prevent constipation

Avoid strenuous activity. Rest. Drink fluids to replace losses. Call for medical help if diarrhea persists.

What should be done to prevent diarrhea?

• Eat small meals. • Drink liquids between meals. • Sit up while eating; elevate your head when lying down. • Wait 3 hours after eating before lying down. • Wait 2 hours after eating before exercising. • Refrain from wearing tight-fitting clothing. • Avoid foods, beverages, and medications that aggravate your heartburn. Common irritants include foods that are fried or high in fat; chocolate and peppermint; coffee, alcoholic beverages, and carbonated beverages; mustard, ketchup, and tomato sauces; acidic substances such as vinegar, citrus juices, and citrus fruits. • Refrain from smoking cigarettes or using tobacco products. • Lose weight if overweight.

What should be done to prevent heartburn

Eat bothersome foods in moderation

What should be done to prevent intestinal gas

heimlich maneuver

What should be performed to save a choking person

gallbladder, pancreas

What stimulates the release of cholecystokinin?

pancreas

What stimulates the secretion of secretin

Fat in the intestine stimulates cells of the intestinal wall to release the hormone cholecystokinin (CCK). This hormone travels by way of the blood to the gall- bladder and stimulates it to contract, which releases bile into the small intestine. Cholecystokinin also travels to the pancreas and stimulates it to secrete its juices, which releases bicarbonate and enzymes into the small intestine. Once the fat in the intestine is emulsified and enzymes have begun to work on it, the fat no longer pro- vokes release of the hormone, and the message to contract is canceled. (By the way, fat emulsification can continue even after a diseased gallbladder has been surgically removed because the liver can deliver bile directly to the small intestine.)

When fat is present in the intestine, the gallbladder contracts to squirt bile into the intestine to emulsify the fat. How does the gallbladder get the message that fat is present?

The pyloric sphincter opens to let out a little chyme, then closes again. How does it know when to open and close?

When the pyloric sphincter relaxes, acidic chyme slips through. The cells of the pyloric muscle on the intestinal side sense the acid, causing the pyloric sphincter to close tightly. Only after the chyme has been neutralized by pancreatic bicarbonate and the juices surrounding the pyloric sphincter have become alkaline can the muscle relax again. This process ensures that the chyme will be released slowly enough to be neutralized as it flows through the small intestine. This is important because the small intestine has less of a mucous coating than the stomach does and so is not as well protected from acid

small intestine

Where does most absorption take place?

stomach wall

Where is gastrin secreted from

duodenal wall

Where is secretion secreted from?

older adults, alzheimers disease, Parkinsons disease, or pneumonia

Who is most vulnerable to choking?

The pancreas protects itself from harm by producing an inactive form of the enzymes.* It releases these proteins into the small intestine, where they are activated to become enzymes. In pancreatitis, the digestive enzymes become active within the infected pancreas, causing inflam- mation and damaging the delicate pancreatic tissues.

Why don't the digestive enzymes damage the pancreas?

peptic ulcer

a lesion in the mucous membrane of either the stomach (gastric ulcer) or the duodenum (duodenal ulcer)

Ulcer

a lesion of the skin or mucous membranes characterized by inflammation and damaged tissues

appendix

a narrow blind sac extending from the beginning of the colon that contains bacteria and lymph cells

villi function

absorb nutrients

Large intestine (Colon)

absorbs water and minerals; passes waste (fiber, bacteria, and unabsorbed nutrients) along with water to the rectum

colon

absorbs water and recycles dissolved salts

Bile function

acts as emulsifier that disperses fat in watery solutions

chyme

after bolus is digested in the stomach, the semiliquid food that moves to small intestine

ileocecal valve function

allow contents of small intestine to empty into large intestine

Esophageal sphincters

allow passage from mouth to esophagus and from esophagus to stomach/ prevent back flow from stomach to esophagus and from esophagus to mouth

Trachea

allows air to pass to and from lungs

celiac disease

an intestinal disorder in which the inability to absorb gluten results in an immune response that damages intestinal cells; also called celiac sprue, nontropical sprue, or gluten-sensitive enteropathy.

Microbes in the GI tract....

are influenced by prebiotics and probiotics, thus by one's diet

Digestion

breaks down food into nutrients, which can then be broken down further into energy

Stomach

churns, mixes, and grinds food to a liquid mass; adds acid, enzymes, and fluid

pyloric sphincter

circular muscle that separates the stomach from the small intestine and regulates the flow of partially digested food into the small intestine

Lymph

clear fluid that contains infection fighting white blood cells

Saliva

contain water, salts, mucus, and enzymes to start digestion of carbohydrates/ protect teeth and linings of mouth, esophagus, and stomach

vomiting

contents of stomach propelled through esophagus to the mouth and expelled

Pharynx

directs food from mouth to esophagus, the passageway leading from the nose and mouth to the larynx and esophagus

undigested residues

exercise intestinal muscles

Bacteria

ferment some fibers

villi

fingerlike projections from the folds of the small intestine

Liver function

first to receive nutrients absorbed from the GI tract/ defends body by detoxifying substances that might cause harm and prepares waste products for excretion

prebiotics

food components (such as fiber) are not digested by the human body but are used as food by the GI bacteria to promote their growth and acitivty

Pyloric sphincter function

holds chyme in stomach long enough to mix with gastric juice and liquefy/ prevent intestinal contents from backing up into stomach

anus

holds rectum closed, opens to allow elimination/ the terminal outlet of the GI tract

segmentation

inner circular muscles contract and relax in a way that churns the chyme mixing it with digestive juices

Lumen

inner space of intestines

probiotics

living microorganisms found in foods and dietary supplements that when consumed in sufficient quantities are beneficial to health

ileocecal valve

located at the beginning of the large intestine (colon)/ separates the small and large intestine

Pancreas

manufactures enzymes to digest all energy-yielding nutrients and releases bicarbonate to neutralize acid chyme that enters the small intestine

Bolus

mass of chewed swallowed food

yogurt

milk products produced by fermentation of lactic acid

Lymphatic system

network of tissues and organs that transport fluids toward the heart or carry products of fat digestion into the bloodstream

Active Transport

nutrients such as glucose and amino acids require energy to move against a concentration gradient

Facilitated transport

nutrients such as water soluble vitamins need a specific carrier to transport them from one side of the cell membrane to the other

Upper Esophageal sphincter function

opens in response to swallowing

peristalsis

outer longitudinal muscles that rhythmically contract in a wavelike motion that move chyme forward

flatulence

passage of excessive amounts of intestinal gas

Rectum function

prevents continuous elimination

Lower Esophageal sphincter function

prevents reflux of stomach contents

Mouth

process of digestion begins, chew and mixes food with saliva

Benefit of bacteria in GI tract

produce several vitamins, digest and metabolize fibers

Bile

produced by the liver, stored in gallbladder, and flows into duodenum

Epiglottis

protects airway during swallowing/ cartilage in the throat that guards the entrance to the trachea and prevents fluid or food from entering it when a person swallows

Fiber

retains water

diverticulosis

sacs or pouches develop in weakened areas of the intestinal wall that are inflammed. common in colon

small intestine

secretes enzymes that digest all energy-yielding nutrients to smaller nutrient particles; cells of wall absorb nutrients into blood and lymph

Diaphragm

separates the abdomen from the thoracic cavity

Simple diffusion

small nutrients (water and small lipids) cross into intestinal cells freely

capillaries

small vessels that connect arteries to veins/ exchange of oxygen nutrients and wastes

Gallbladder

stores bile until needed

rectum

stores waste prior to elimination/ the muscular terminal part of the intestine, extending from the sigmoid colon to the anus

laxatives

substances that loosen bowels and prevent or treat constipation

Intestinal glands: Target Organ, secretion, and action

target organ: small intestine/ secretion: intestinal juice/ action: intestinal enzymes break down carbohydrate, fat, and protein fragments; mucus protects the intestinal wall

Esophagus

the food pipe, the conduit from the mouth to the stomach

thoracic duct

the main lymphatic vessel that collects lymph and drains into the left subclavian vein

Hepatic portal vein

the vein that collects blood from the GI tract and conducts it to the liver

subclavian vein

the vein that provides passageway from the lymphatic system to the vascular system

arteries

vessels carry blood from the heart to the tissues

veins

vessels carry blood to the heart

categorized by frequent watery stools. intestinal contents move too quickly to allow water resportion.

what is diarrhea

antacids and acid controlers

what should be taken to provide relief to GERD

intestinal wall

where is cholecystokinin secreted from