Chapter 3
The stomach holds food for
2-4 hours
Sphincters**(know all of them)
A muscular and circular valve in the GI tract that controls the flow of food stuff
Some nutrients such as glucose and amino acids must be absorbed actively through _____.
Active transport
Pepsin *
An enzyme that breaks down proteins
Last sphincter of the body
Anal sphincter
_____ may help indigestion
Antacids and acid controllers
The pancreas also produces ___, which is needed to neutralize chyme
Bicarbonate(very acidic)
Gallbladder stores ___ that is produced in the liver
Bile *
Vomiting
Body's adaptive mechanism Dehydration is a concern. May be self-induced as in eating disorders
Found at the end of the esophagus
Cardiac sphincter
Prevents reflux of stomach content to cause heartburn and ulcers
Cardiac sphincter
"Waste"
Cecum(first part of large intenstine) Ascending colon Transverse colon Descending colon Sigmoid colon
Stimulated by the presence of fat and protein in the duodenum
Cholecystokinin
The ____ passes by the opening of the appendix
Chyme
The stomach adds gastric juices and grinds the bolus to a semi liquid mass called
Chyme *
Saliva
Comes from salivary glands, moistens food
Constipation
Defecation habits are different among people. Many causes are possible. Hemorrhoids may be a problem. Diverticulosis is a condition in which the intestinal walls weaken and bulge. The bulging pockets are called diverticula. Diverticulitis is a worsened condition and requires intervention. Use of laxatives, enemas and mineral oil may not be necessary with lifestyle changes.
By the time food crosses the ____, most nutrients are absorbed
Duodenum
Cholecystokinin originates from the
Duodenum
Chyme
Duodenum Ileum Jejunum
Final stage of digestion
Energy-yielding nutrients are disassembled for absorption. Vitamins, minerals and water can be absorbed. Undigested residues, including some fibers, continue through the digestive tract and form stool. Recycling of usable materials
Some nutrients, such as the water-soluble vitamins, are absorbed by _______.
Facilitated diffusion
T/F The environment in the stomach is poorly acidic due to the hydrochloric acid
False, very acidic
Rectum
Fecal material is stored Stimulates elimination
Choking
Food becomes lodged in the trachea. The larnyx cannot make sounds. The Heimlich maneuver may need to be used.
Diarrhea
Frequent, loose, watery stools Irritable bowel syndrome or colitis is one of the common GI disorders.
Stimulates contraction of gallbladder and flow of bile into the small intestine*
Function of Cholecystokinin
Stimulates the release of enzyme rich pancreatic fluids*
Function of Cholecystokinin
Heartburn and "Acid Indigestion"
Gastroesophageal reflux is the backward flow of stomach contents into the esophagus
The _____ of the stomach wall secrete mucus to protect the walls of the stomach from the high acidity levels that are measured by pH units.
Goblet cells
Strategies of constipation
High-fiber diet Increased fluids Exercise regularly. Respond quickly to the urge to defecate.
Between the small and large intestine
Ileocecal sphincter
Prevents large intestine content (bacteria) back up into the small intestine
Ileocecal sphincter
The Secretions of Digestion
Includes digestive enzymes that act as catalysts in hydrolysis reactions
Millions of bacteria colonize the
Large intesntion
The large intestine
Little digestion occurs
The Stomach is located between the _____ sphincter and _____sphincter
Lower esophageal, pyloric
The Pancreas
Manufactures digestive enzymes
the microscopic hairlike projections on each villi
Microvilli
Food Bolus
Mouth Esophagus Stomach
Accessory Organs
Pancreas Gallbladder Liver
_____is the action pushing the intestinal contents along
Peristalsis**
Between the stomach and small intestine
Pyloric sphincter
Controls the amount of stomach content into the small intestine
Pyloric sphincter
Strategies to avoid diarrhea
Rest Drink fluids Medical help is needed if it persists.
Salivary envymes
Salivary amylase Lingual lipase
Stimulated by the presence of acidic chyme and the presence of peptones in the duodenum
Secretin
Hormones
Secretin Cholecystokinin
Function of the stomach
Secretion of hydrochloric acid and gastric enzymes, mainly pepsin *
Some nutrients, such as water and small lipids, are absorbed by _______.
Simple Diffusion
Nutrients can be absorbed through
Simple diffusion Facilitated diffusion Active transport
Strategies to avoid choking
Small bites Chew thoroughly. Don't talk or laugh with food in the mouth. Don't eat when breathing hard.
Controls the amount of bile into the small intestine
Sphincter of Oddi
Function of secretin *
Stimulates the secretion of bicarbonate from the pancreas
Belching and Gas
Strategies Eat slowly. Chew thoroughly. Relax while eating. Watch bothersome foods.
______ has the strongest muscles in the GI tract
The Stomach
____ transports bile from the gallbladder into the small intestine
The common bile duct
_____is the flexible muscular tube from mouth to anus
The gastrointestinal (GI) tract
Beginning of the digestive system
The mouth
Chyme *
The semiliquid mass of food
The esophagus
Tube that leads the bolus to the stomach. There is a sphincter at the upper and lower (also known as the cardiac sphincter) ends of the esophagus.
the fingerlike projections within the folds of the small intestine that move in a wave-like pattern to trap nutrients
Villi
intrinsic factor
Vital for vitamin B12 absorption Secreted by the stomach
________ are absorbed in the large intestine
Water, sodium and potassium
The Circulatory System
Water-soluble nutrients and small fats enter the bloodstream, are routed to the liver before being transported to the cells
The Muscular Action of Digestion is under ____ control
autonomic
Small mouthful of food that are swallowed are called a
bolus *
Pancreatic lipase *
breaks down lipids
Pancreatic protease *
breaks down proteins
Pancreatic amylase *
breaks down starch
Salivary amylase *
breaks down starch into
Results in the formation of ____
chyme *
Stomach action involves
circular, longitudinal, and diagonal muscles
The epiglottis *
closes to prevent food from entering the pharynx(lungs)
Gastric juice
comes from the gastric glands and includes hydrochloric acid
Segmentation
contractions by circular muscles that contract and squeeze contents to promote mixing with digestive juices Mainly occurs in the intestine
The hepatic portal vein
directs blood from the GI tract to the liver
Secretin originates from the
duodenum
Hiccups are triggered by
eating or drinking too fast.
Function of Fat-soluble nutrients*
enter the lymphatic system*, bypass the liver at first and eventually enter the vascular system.
What does the enormous surface area of the small intestine do?
facilitates nutrient absorption
The small intestine receives digestive juices from the
gallbladder and the pancreas
The pancreas produces
glucagon and insulin
The large intestine (colon) begins at the _____ and ends at the_____.
ileocecal valve, rectum and anus
Pancreatic juice contains
intestinal enzymes (carbohydrase, lipase, protease) and bicarbonate
Bile is produced by the ___, stored in the _____, and acts as an emulsifier to suspend fat
liver, gall bladder
Digestion in the mouth involves
mastication (chewing), the stimulation of taste buds, and swallowing.
Lingual lipase
more effective in breaking down milk fats in infants
Function of sphincter contractions
open and close passageways. This prevents reflux and controls the passage of contents
Mucus layer
prevents autodigestion
Bile
produced by the liver, stored in the gall bladder, and acts as an emulsifier to break down fat
The pyloric sphincter
regulates the flow of partially digested food into the small intestine.
Cholecystokinin *
stimulates release of bile from the gallbladder
The hepatic vein
takes blood from the liver to the heart.
The three segments of the small intestine
the duodenum, the jejunum and the ileum.
Digestion
the process of breaking down foods into nutrients to prepare for absorption
Crypts
the tubular glands that lie between the intestinal villi Digestible secretions
Bacteria produce
vitamins - biotin and vitamin K
Capacity of the stomach
~4 cups