Download The Digestive System

PowerPoint® to accompany
Medical Assisting
Chapter 31
Second Edition
Ramutkowski  Booth  Pugh  Thompson  Whicker
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
1
The Digestive System
Objectives
31-1 Spell, define, and correctly use the Key Terms in
this chapter.
31-2 List the functions of the digestive system.
31-3 Trace the pathway of food through the alimentary
canal.
31-4 Describe the structure and functions of the mouth,
teeth, tongue, and salivary glands.
31-5 Describe the structure and function of the
pharynx.
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The Digestive System
Objectives (cont.)
31-6 Describe the swallowing process.
31-7 Describe the structure of the esophagus and tell
how it propels food into the stomach.
31-8 Describe the structure and functions of the
stomach.
31-9 List the substances secreted by the stomach and
give their functions.
31-10 Describe the structure and functions of the small
intestine.
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The Digestive System
Objectives (cont.)
31-11 List the substances secreted by the small
intestine and describe the importance of each.
31-12 Explain the structures and functions of the liver,
gallbladder, and pancreas.
31-13 List the substances released by the liver,
gallbladder, and pancreas into the small
intestine and give the function of each
secretion.
4
The Digestive System
Objectives (cont.)
31-14 Describe the structure and functions of the large
intestine.
31-15 Tell what types of nutrients are absorbed by the
digestive system and where they are absorbed.
31-16 Describe the signs, symptoms, causes, and
treatments of various disorders and diseases of
the digestive system.
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Introduction
 Digestion
 The mechanical and chemical breakdown of
foods into forms that your body cells can
absorb
 The organs of the digestive system carry out
digestion.
 Two categories
 Those of the alimentary canal
 The accessory organs
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Alimentary Canal
 Length of the entire canal is about 9 meters (29
feet)
 Mucosa - absorbs
 Serosa - secretes
nutrients
serous fluid to keep
the outside of the
 Submucosa - carry away
canal moist and
absorbed nutrients
prevent it from
 Muscular layer - move
sticking
to
other
materials through the
organs.
canal
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Mouth, Teeth, Tongue, and
Salivary Glands



Mouth takes in food and
reduces its size through
chewing
Salivary glands - saliva
(spit) contains an enzyme
that will break down
carbohydrates
Teeth act to decrease the
size of food particles and
different types of teeth
are adapted to handle
food in different ways
8
Apply Your Knowledge
What is the purpose of the serosa?
9
Apply Your Knowledge -Answer
What is the purpose of the serosa?
Serosa - secretes serous fluid to keep the outside
of the alimentary canal moist and prevent it
from sticking to other organs.
10
Pharynx
The throat - long,
muscular structure that
extends from the area
behind the nose to the
esophagus
 Nasopharynx
 Oropharynx
 Acts to connect the
nasal cavity with
the oral cavity for
breathing through
the nose
 Acts to push food
into the esophagus
 Laryngopharynx
11
Swallowing Process
An involuntary automatic
response (reflex)
1. Soft palate raises causing
the uvula to cover the opening
between the nasal cavity and
oral cavity
2. Epiglottis covers the
opening of the larynx
12
Swallowing Process (cont.)
3. Muscles in the pharynx
contract, forcing food
toward the esophagus
4. Esophagus opens
5. Food is pushed into the
esophagus by the muscles
of the pharynx
13
Esophagus
 Esophagus is a muscular tube about 25
cm long that connects the pharynx to the
stomach
 Esophageal sphincter controls the
movement of food into the stomach
 Opens and closes to allow or prevent
movement of substances out of a tube
14
Stomach
 Below the diaphragm in the
upper left region of the
abdominal cavity
 It functions to receive food
from the esophagus
 Mix food with gastric juice
(secretions of the stomach
lining)
 Start protein digestion
 Move food into the small
intestine
Click for Larger View
15
Stomach (cont.)
16
Stomach Secretions
When a person smells, tastes, or sees
appetizing food, the parasympathetic
nervous system stimulates the gastric
glands to secrete their products.
Gastrin, made by the stomach, also stimulates
gastric glands to become active.
Chief cells - secrete pepsinogen, which
becomes pepsin in the presence of acid.
Pepsin digests proteins.
17
Stomach Secretions (cont.)
Parietal cells –
 secrete hydrochloric acid, that convert pepsinogen
to pepsin.
 secrete intrinsic factor, which is necessary for
vitamin B12 absorption.
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Small Intestine
 Small intestine is a
tubular organ that
extends from the
stomach to the large
intestine
 Carries out most
digestion in the body
and is responsible for
absorbing most of the
nutrients into the
bloodstream
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Small Intestine - Secretions
 Peptidases enzymes that digest
proteins.
 Intestinal lipase - an
enzyme that digests
fats
 Sucrase, maltase,
and lactase - Digest
sugars.
 If a person
cannot produce
lactase, he will not
be able to digest
lactose, which is
the sugar in dairy
products - lactose
intolerance
20
Apply Your Knowledge
Your patients states that she is lactose
intolerant. What does that mean?
21
Apply Your Knowledge -Answer
Your patient states that she is lactose
intolerant. What does that mean?
She cannot produce lactase and cannot digest
lactose, which is the sugar in dairy products; thus,
she is lactose intolerant.
22
Pancreas
Pancreas is located behind the stomach.
Pancreatic acinar cells produce pancreatic juice.
Pancreatic juice contains the following enzymes:
Pancreatic amylase digests carbohydrates
 Pancreatic lipase digests lipids
 Nucleases - digests
nucleic acids


Trypsin, chymotrypsin,
and carboxypeptidase digest proteins
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Liver




Reddish-brown in color
Large organ that fills most of the upper right
abdominal quadrant
Has a large right lobe and a small left lobe separated into smaller divisions called hepatic
lobules. Hepatic lobules contain macrophages
that destroy bacteria and viruses in the blood
Stores vitamins and iron
24
Liver (cont.)
 Each hepatic lobule contains many cells
called hepatocytes
 Process the nutrients in blood and make bile, which
is used in the digestion of fats
 Bile leaves the liver through the hepatic duct
25
Gallbladder



Small sac-like structure
located beneath the liver
Only function is to store
bile
Cholecystokinin causes
the gallbladder to release
bile
Gallbladder
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Large Intestine
Large intestine
extends from
the ileum of the
small intestine
to where it
opens to the
outside world as
the anus
27
Large Intestine (cont.)


Lining of the large
intestine - secretes
mucus to aid in the
movement of
substances
Large intestine
absorbs water and a
few electrolytes from
chyme; the left over
forms feces
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The Absorption of Nutrients
Nutrients are defined as necessary food
substances and are absorbed in the small
intestine






Carbohydrate
Proteins
Lipids
Vitamins
Minerals
Water
29
Apply Your Knowledge
Why can a person live without their
gallbladder?
30
Apply Your Knowledge -Answer
Why can a person live without their
gallbladder?
It’s only purpose is to store bile. As long as a
person is still making bile in the liver, they can still
digest fats.
31
Diseases and Disorders of the
Digestive System
Appendicitis - an inflammation
of the appendix
Causes
 Blockage of appendix with feces
 Blockage of appendix with tumor
Treatments
 Surgery to remove appendix
 Antibiotics to prevent infection
Signs and
symptoms – lack of
appetite, pain in and
around the navel
area or in the
abdomen, nausea,
slight fever, pain in
the right leg, and
increased white
blood cell content
32
Diseases and Disorders
of the Digestive System
 Cirrhosis - a long lasting liver disease in which
normal liver tissue is replaced with nonfunctional
scar tissue
 Causes - Excessive alcohol consumption
 Hepatitis C infection
 Hepatitis B infection
 Treatment - Liver transplant
 Lifestyle changes to stop medications or use of
alcohol
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Diseases and Disorders
of the Digestive System (cont.)
 Colitis - defined as inflammation of the large
intestine
 Causes - caused by viral or bacterial infection or the
use of antibiotics. Ulcers in the large intestine,
Crohn’s disease, various other diseases, and stress
may contribute.
 Treatments




Treating underlying causes
Changing antibiotics
Fluids
Repair of ulcers
34
Diseases and Disorders
of the Digestive System (cont.)
 Colorectal cancer usually comes from the lining of the
rectum or colon.
 Causes - mostly unknown. Polyps in colon or rectum can
become cancerous.
 Signs
 Changes in bowel movement
 Blood in feces
 Anemia
 Abdominal pain
 Weight loss
 Narrow feces
35
Diseases and Disorders
of the Digestive System (cont.)
 Crohn’s disease - a common type of inflammatory
bowel disease and is an autoimmune disorder that
typically affects the end of the small intestine
 Causes - this is an autoimmune disorder.
 Treatment




Medications to reduce inflammation
Antibiotics
Surgery to remove affected part of intestine
Changes in diet
36
Diseases and Disorders
of the Digestive System (cont.)
 Diverticulitis - inflammation of diverticuli in the intestine.
Diverticuli are abnormal dilations in the intestinal wall
 Causes – mostly unknown. Lack of fiber in diet and bacterial
infection of the diverticuli.
 Signs
 Abdominal pain
 Constipation
 Diarrhea & nausea
 Fever
 Blood in feces
 High white blood cell count
37
Diseases and Disorders
of the Digestive System (cont.)
 Gastritis - an inflammation of the stomach lining
 Causes - bacteria or viruses, some medications,
alcohol, spicy foods, excessive eating poisons, and
stress.
 Treatment
 Cook food properly to kill bacteria/viruses
 Avoid foods/medications that irritate stomach
linings
 Begin acid reducing medications
38
Diseases and Disorders
of the Digestive System (cont.)
 Heartburn - called gastroesophageal reflux disease (GERD) occurs when stomach acids are pushed into the esophagus
 Causes – alcohol, some foods, defective esophageal sphincter,
pregnancy, obesity, hiatal hernia, and repeated vomiting.
 Treatment
 Reducing weight
 Diet changes
 Reduce alcohol consumption
 Medications
 Not lying down after meal
39
Diseases and Disorders
of the Digestive System (cont.)
 Hemorrhoids - varicose veins of the rectum
or anus
 Causes – constipation, excessive straining
during bowel movements, liver disease,
pregnancy, and obesity.
 Treatment




Eating high fiber
Stool softeners
Medications
Surgery
40
Diseases and Disorders
of the Digestive System (cont.)
 Hepatitis - inflammation of the liver.
 Causes - bacteria, viruses, parasites, immune
disorders, the use of alcohol and drugs, and
overdose of acetaminophen.
 Treatment
 Avoid drugs and alcohol
 Prescribed medications
41
Diseases and Disorders
of the Digestive System (cont.)






Hiatal hernia - occurs when a portion of the stomach
protrudes into the chest through an opening in the
diaphragm.
Inguinal hernias - occurs when a portion of the large
intestine protrudes into the inguinal canal.
Oral cancer - usually involves the lips or tongue, but can
occur anywhere in the mouth.
Pancreatic cancer – 4th leading cause of death in the
U.S.
Stomach cancer - most common in the upper part of the
stomach.
Stomach ulcers - occur in the lining of the stomach
42
Apply Your Knowledge
Your patient has been diagnosed with
Crohn’s disease. What is the usual
treatment for this disease?
43
Apply Your Knowledge -Answer
Your patient has been diagnosed with
Crohn’s disease. What is the usual
treatment for this disease?
Treatment for Crohn’s disease includes
medications to reduce inflammation,
antibiotics, surgery to remove affected part of
intestine and/or changes in diet
44
Summary
Medical Assistant
Knowledge of the
digestive system will
assist you in providing
care for the patient with
diseases and disorders of
the digestive system.
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End of Chapter
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