Download Digestive System

Chapter 5
Digestive System
Oral cavity.
Fig. 5-1
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Upper permanent teeth with the dental arch.
Fig. 5-2
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Anatomy of a tooth.
Fig. 5-3
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Salivary glands.
Fig. 5-4
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3 functions of Digestive System
• 1. Digestion
• 2. Absorption
• 3. Elimination
Digestive System
• Pharynx/throat- muscular tube lined with a
mucous membrane and serves as a
common passageway for air traveling to
nasal cavity, trachea, and food going to the
esophagus
• Epiglottis- flap in back of throat that covers
trachea so food can’t enter trachea
Digestive System
• Esophagus- eso=inward, phag/o=to swallow; it
is a 9”-10” tube that extends from pharynx to
stomach.
• **Rhythmic contractions of muscles propels food
towards the stomach
– Peristalsis- peri=surrounding, -stalsis=contraction:
is the involuntary contraction of the esophagus
• Ileus- failure of peristalsis
• Achalasia= (-chalasia= relaxation); failure of the
lower esophagus sphincter to relax so food
cannot pass
• Dysphagia- (dys=bad; phagia=eat or swallow);
difficulty in swallowing/eating
Digestive System
• Bolus- semisolid food going through esophagus
into upper portion of stomach called the fundus.
Food then goes to the body of the stomach or the
middle section, and then the lower portion called
the antrum.
• Sphincter- muscle rings controlling the openings
into and out of the stomach: Pyloric sphincterring at distal end of stomach that allows food to
leave stomach. Cardiac sphincter- ring at
superior portion of stomach- relaxes and
contracts food from esophagus into the stomach.
Parts of the stomach.
Fig. 5-7
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Stomach
• *Mucous lines the stomach in folds called
rugae which contains digestive glands that
produce pepsin enzymes and hydrochloric
acid . This begins the process of digestion.
Food digests in about 1-4 hours where it is
chemically and mechanically prepared for
the sm intestine to digest and absorb into
the blood stream.
The gastrointestinal tract.
Fig. 5-6
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Small Intestine
• Small Intestine (3 parts)- millions of tiny
villi line walls of sm intestines; these tiny
villi absorb the digested nutrients into the
bloodstream and lymph vessels
– Duodenum- receives food from the
stomach as well as bile from the liver, gall
bladder, and pancreas
– Jejunum
– Ileum (leads to the lg intestines)
Villi in the lining of the small intestine.
Fig. 5-8
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Large Intestines
• Large Intestines (6 parts): goes from the end of ileum to
anus; receives waste products of digestion (not able to be
absorbed into bloodstream) and then stores them until they
are released as feces/defecation.
• Cecum- pouch on rt side and connects to ileum
• (appendix hangs from the cecum)
• Ascending colon- going from cecum to liver; it then turns left
and becomes:
• Transverse colon- then passes horizontally towards spleen
and becomes:
• Descending colon
• Sigmoid colon- “s” shaped; lies at distal end and leads to the
• Rectum- (then goes to the anus)
The gastrointestinal tract.
Fig. 5-6
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Pathway of food thru GI track
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Oral cavity
Pharynx
Esophagus
Stomach
Duodenum
Jejunum
Ileum
Cecum
Ascending Colon
Transverse Colon
Descending Colon
Sigmoid Colon
Rectum
Anus
Accessory organs of Digestion:
Liver (hepat/o)- manufactures bile which contains
cholesterol, acids, and pigments such as bilirubin;
regulates glucose in blood and stores it as glycogen.
(Cirrohosis is liver disease resulting from alcoholism
and malnutrition); bile leaves the liver via the hepatic
duct which goes to the cystic duct leading to the
gallbladder
• Gallbladder (cholecyst/o)- contracts to force out bile
to the cystic duct into the common bile duct (which
carries bile into the duodenum)
• Pancreas (pancreat/o)- secretes enzymes and the
hormone insulin that travel through the pancreatic
duct to duodenum. It is here that bile breaks apart
large fat globules which is called emulsification.
Without bile, most fat would be undigested. The
pancreas produces enzymes to digest starch called
amylase. Lipase digests fats; pepcin digests proteins.
•
Ducts
• Hepatic duct- takes bile from the liver and
travels to the cystic duct
• Cystic duct- leads to/from gallbladder
• *After food is in the stomach the
gallbladder contracts forcing bile from the
cystic duct into the common bile duct;
meanwhile the pancreas secretes enzymes
into the pancreatic duct
• Common Bile duct- carries bile from liver
and gallbladder to the duodenum
Liver, gallbladder, and pancreas
Fig. 5-9
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Pathways of food through the gastrointestinal tract.
Fig. 5-12
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Terms and Procedures
• Crohn’s Disease- Chronic inflammation of the intestinal tract;
IBD (inflammatory bowel disease)
• *Cholelithiasis- gallstones
• *Ascites- abnormal accumulation of fluid in abdomen
• Hepatitis A- viral; spread by contaminated food or water;
complete recovery
• Hepatitis B- viral; transmitted by blood transfusion, sexual
contact, or use of contaminated needles; severe infection can
cause destruction of liver cells, cirrhosis, or death. *A vaccine
is provided for healthcare workers
• Hepatitis C- viral; transmitted by blood transfusions or needle
inoculations and may cause chronic hepatitis
• Hemorrhoids- swollen, twisted, varicose veins in the rectal
region
Terms and Procedures
• Ulcerative Colitis- chronic inflammation of the colon with
presence of ulcers; chronic, idiopathic recurrent diarrheal
disease
• Peritonitis- inflammation of the peritonium
• IBS- Irritable Bowel Syndrome; group of gastrointestinal
symptoms associated with stress and tension
• Stool Guaiac or Hemoccult- test for blood in feces
• Barium Swallow- upper GI; x-ray images of the esophagus,
stomach, and small intestine obtained after administering
barium by the mouth
• Barium Enema- lower GI; x-ray images of the colon and
rectum obtained after injection of barium into the rectum
• Oral leukoplakia- white plaques or patches on the mucosa of
the mouth
Sigmoid colostomy.
Fig. 5-14AB
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A) Three types of anastomoses= surgical opening b/w organs in body
B) Mesentery= membrane in the middle of intestines holding together
Fig. 5-15AB
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Ascites=abnormal accumulation of fluid in abdomen when fluid seeps out
of bloodstream and collects in peritoneal cavity
Fig. 5-16
(From Lewis SM, Collier IC, Heitkemper MM: Medical-Surgical Nursing,
4th edition, St. Louis, Mosby, 1996, page 1274.)
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A)Anal fistula and two types of polyps
B) Multiple polyps of the colon (polyposis)
Fig. 5-18AB
(Part B from DAmjanov I: Pathology for the Health-Related Professions,
Philadelphia, WB Saunders, 1996, page 281.)
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A) Diverticula=abnormal side pockets in intestinal wall traps
bacteria
B) Esophageal varices= swollen tortuous vein
A
B
Fig. 5-20AB
(Part B from DAmjanov I: Pathology for the Health-Related Professions,
Philadelphia, WB Saunders, 1996, page 261.)
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Hernias.
Fig. 5-21
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Intussusception =telescoping of intestines
volvulus= twisting of intestines upon itself
Fig. 5-22
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A) Liver with alcoholic cirrhosis
B) Cholesterol Gallstones
A
B
(Part A from Damjanov I: Pathology for the Health-Related Professions, Philadelphia,
WB Saunders, 1996, page 301; Part B from Kumar V, Cotran RS, and Robbins S:
Basic Pathology, 6th ed., Philadelphia, WB Saunders, 1997, page 551.)
Copyright © 2001 by W. B. Saunders Company. All rights reserved.
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Fig. 5-23AB
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