Transcript Chapter 11 A & P of the Human Body

CHAPTER
11
Anatomy and
Physiology of the
Human Body
UNIT
10
The Digestive System
11 - 2
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Defining Digestion


Digestion is the activity performed by the
organs of the digestive system.
Digestion is defined as the process by
which food is broken down, mechanically
and chemically, in the gastrointestinal
tract into enzymes that are usable by the
cells of the body.
11 - 3
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The 4 Phases of the Digestive Process
1.
2.
3.
4.
Ingestion: taking in food and water
Digestion: breaks food down into
nutrients
Absorption: enzymes used in the
intestines
Elimination: urination or defecation of
waste
11 - 4
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Raw Materials Required
for a Healthy Body




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Carbohydrates provide energy.
Proteins build and repair cells and tissue.
Fats are a secondary energy source.
Minerals
(continued)
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Raw Materials Required
for a Healthy Body



Vitamins are chemicals needed for
growth and to control bodily activities.
Water regulates temperature, adds
moisture to waste, and lubricates.
Roughage speeds up the digestive
process.
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The Pathway of Food through
the Gastrointestinal (GI) Tract
11 - 7
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The Structures of the Mouth
Teeth


Break up food to make it
easier to swallow and
prepare it to become
digestive enzymes
Tongue


Moves food around within
the mouth to bring it into
contact with the teeth
Salivary glands


3 glands that begin the
chemical process of
breaking down food
11 - 8
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The Digestive Process That
Occurs in the Mouth



Teeth chop and grind down the food.
The salivary glands secrete the enzyme
ptyalin to break down carbohydrates into
sugars.
The saliva also cleans the teeth; the
combination of mashed foods and saliva
is called a bolus.
11 - 9
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The Process of Swallowing

The bolus can go in three directions:
1.
2.
3.

11 - 10
Up the nose
Down and forward into the trachea
Down into the esophagus
The bolus raises the soft palate as it is
swallowed and closes off the nasal
cavity.
(continued)
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The Process of Swallowing



The epiglottis moves across the opening
to the larynx as the tongue pushes the
bolus against the palate.
At the moment of swallowing, the larynx
moves upward against the epiglottis to
close the opening off to the larynx.
The bolus enters the esophagus.
11 - 11
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How the Esophagus Works


Involuntary muscle action, called
peristalsis, moves the bolus down the
esophagus by alternately contracting and
relaxing against the bolus.
The bolus then moves down into the
stomach.
11 - 12
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The Structure and Function
of the Stomach


11 - 13
The upper opening to the stomach is
called the cardiac sphincter.
This sphincter opens to allow the bolus
to enter, and closes to prevent the bolus
from going back up into the esophagus.
(continued)
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The Structure and Function
of the Stomach



11 - 14
The stomach is an organ made up of
three layers of strong muscle tissue.
The stomach has folds, called rugae, that
allow it to expand as the bolus enters.
The stomach begins to contract when the
bolus enters and the bolus is mixed with
gastric enzymes and hydrochloric acid as
the chemical process of breaking down
food continues.
(continued)
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The Structure and Function
of the Stomach


The bolus of partially digested food is
changed into a semiliquid solution called
chyme.
When the consistency of the chyme is
right, the pyloric sphincter muscle at the
end of the stomach opens and allows the
chyme to enter the small intestine.
11 - 15
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The Structure and Function
of the Small Intestine


The small intestine absorbs the nutrients
from the chyme.
At 20 feet in length, the small intestine
has 3 sections:
1.
2.
3.
Duodenum
Jejunum
Ileum
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The Duodenum


The duodenum
receives the highest
concentration of
acids from the
stomach.
It is especially prone
to the development
of ulcers.
11 - 17
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The Functions of the Liver



11 - 18
The largest gland in the body
Secretes bile, which is required to digest
fats
Stores glycogen to be used when the
body needs additional blood sugar.
(continued)
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The Functions of the Liver



Processes proteins that burn fats as fuel
or store fats
Manufactures substances required for
the process of clotting blood
Produces antibodies to counteract
certain disease organisms
11 - 19
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The Portal Circulation
Connection and the Liver

The portal vein conveys absorbed
nutrients and other substances from the
abdominal organs for processing by the
liver.
11 - 20
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The Role of the Gallbladder

The sole purpose of the gallbladder is to
concentrate and store bile to aid in the
digestion of fats.
11 - 21
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The Association of the
Gallbladder and the Liver

The hepatic duct and the common bile
duct, which branches off the gallbladder,
must remain intact and functional for the
liver to function.
11 - 22
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The Location and Function
of the Pancreas


The pancreas lies beneath the stomach
with its head in the curve of the
duodenum.
The pancreas has 2 functions as a gland:
1.
2.
Exocrine gland: secretes pancreatic juices
directly into the duodenum
Endocrine gland: secretes insulin directly
into the bloodstream
11 - 23
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How and Where Nutrients
Are Absorbed




Absorption occurs in the millions of villi that
line the major part of the small intestine.
The swinging motion of the villi keeps the
chyme mixed with digestive juices.
The external cells of the villi absorb nutrients,
minerals, and water from the chyme.
With useful nutrients and other substances
absorbed from the chyme, waste enters the
large intestine.
11 - 24
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The Sections of the Colon




The large intestine is also called the
colon.
The ascending colon continues upward
along the right side of the abdomen.
The transverse colon extends in a loop
across the abdominal cavity.
The descending colon extends down the
left side of the abdomen until it reaches
the edge of the pelvic cavity.
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The Function of the Colon



The large intestine absorbs excess liquid
from the chyme.
This water, plus some salts and proteins,
are filtered out of the blood to be
eliminated in urine.
This waste forms feces to be eliminated
through the rectum.
11 - 26
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The Function of the Rectum

The rectum serves as a collecting area
for feces, the remains of digestion.
11 - 27
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The Structure and Function
of the Anal Canal


The anal canal is a narrow passageway
that extends from rectum to anus.
This passageway is a voluntarily
controlled muscle that is used to empty
the rectum.
11 - 28
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The Structure and Function
of the Anus

The anus is the opening of the anal canal
to the outside of the body.
11 - 29
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Diagnostic Exams
11 - 30
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Colonoscopy



An exam that uses a fiber optic scope to
view the entire large intestine
This exam requires patient preparation to
clear the intestine of feces.
This is indicated in patients with
complaints of diarrhea, constipation,
bleeding, or pain.
11 - 31
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Gastrointestinal X-Rays

Barium swallow


Upper GI

11 - 32
Uses a fluoroscope to view the action of the
esophagus as the patient swallows a
radiopaque liquid called barium
After the barium swallow, additional barium
is swallowed and the passage of the barium
throughout the small intestine is observed.
(continued)
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Gastrointestinal X-Rays

Lower GI

The barium mixture is administered as an
enema and outlines the structure of the
large intestine.
11 - 33
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Gastroscopy


A fiber optic scope is used to view the
esophagus, stomach, and upper
duodenum.
This procedure can also be used to
remove small foreign objects that may be
blocking the air passage.
11 - 34
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Occult Blood Test

This test is performed on feces to detect
the presence of hidden blood in the stool.
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Proctoscopy

An examination of the lower rectum and
anal canal; it’s preceded by a digital
exam that evaluates the condition of the
anal sphincter.
11 - 36
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Sigmoidoscopy


Uses a sigmoidoscope to view the lower
portion of the sigmoid colon and the
rectum
This exam aids in the diagnosis of
inflammation, infection, or ulcerative
conditions.
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Diseases and Disorders
11 - 38
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Anorectal Abscess and Fistula

Anorectal abscesses


Painful, throbbing lumps that are a collection
of exudate.
Fistulas

The escape tracts that exudate may develop
into the rectum.
11 - 39
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Appendicitis and Cirrhosis

Appendicitis


An acute inflammation of the appendix
Cirrhosis

Chronic liver disease that causes
destruction of liver cells; interferes with the
life-preserving functions of the liver
11 - 40
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Colitis and Colostomy

Colitis


Inflammation of the colon; causes
tenderness and discomfort
Colostomy

Surgical creation of an artificial opening of
the colon, allowing fecal material to be
excreted from the body through the
abdominal wall
11 - 41
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Colorectal Cancer and Constipation

Colorectal cancer


Malignancy of the colon or rectum
Constipation

Sluggish bowel action that results in dry,
hard, infrequent bowel movements
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Crohn’s Disease and Diarrhea

Crohn’s disease


Inflammation of any portion of the GI tract
Diarrhea

Repeated passage of unformed waste
characterized by frequent, liquid stools
11 - 43
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Diverticulosis and Esophageal Varices

Diverticulosis


Presence of bulging pouches in the walls of
the GI tract where the lining has pushed into
the surrounding muscle
Esophageal varices

Dilated, tortuous veins in the lower section
of the esophagus that result in fluids
entering the abdominal cavity
11 - 44
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Anal Fissures and Gastroenteritis

Anal fissures


Cracks or tears in the lining of the anus
Gastroenteritis

Inflammation of the stomach and intestines
that causes fever, nausea, abdominal
cramping, diarrhea, and vomiting
11 - 45
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Gastroesophageal Reflux Disease
and Hemorrhoids

Gastroesophageal reflux disease
(GERD)


Results from a backflow of gastric and
sometimes duodenal contents into the
esophagus through the sphincter just above
the stomach
Hemorrhoids

Veins in the folds of the anal canal become
dilated, causing them to bulge or protrude
outside the body
11 - 46
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Hepatitis

Liver infection that can result in cell
destruction and death

Type A


Transmitted through the fecal-oral route when
waste organisms get into food
Type B

Transmitted through blood and sexual contact
with an infected person
11 - 47
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Hernia

Hernia: protrusion of an internal organ
through a natural opening in the body
wall

Hiatal hernia


A portion of the stomach slips through the
diaphragmatic opening at the end of the
esophagus
Inguinal hernia

Spermatic cords pass through the lower
abdominal walls
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Ileostomy

Surgical opening of the ileum to allow the
chyme of the small intestine to empty
through the abdominal wall
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Irritable Bowel Syndrome


Chronic or periodic diarrhea and
alternating constipation
This condition is also called spastic
colon.
11 - 50
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Oral Cancer


About 90% of oral cancers are
squamous cell cancers that develop in
the tissue linings of the mouth, lip,
tongue, and throat.
The use of snuff or tobacco, alcohol
abuse, and overexposure to the sun are
the primary risk factors for oral cancers.
11 - 51
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Pancreatitis and Paralytic Ileus

Pancreatitis



Chronic or acute inflammation of the pancreas
Enzymes that are normally produced and
excreted into the pancreatic duct remain and
digest pancreatic tissue
Paralytic ileus


Physiological intestinal obstruction that usually
occurs in the small intestine
Peristalsis is either dramatically reduced or totally
absent.
11 - 52
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Peptic Ulcer

Encircled lesions in the mucous
membrane lining of the stomach, lower
esophagus, duodenum, or jejunum
11 - 53
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Polyps and Pruritus Ani

Polyps


Mass of tissue that results from an
overgrowth of upper epithelial cells in the
mucosal membrane of the GI tract
Pruritus ani

Itching of the areas surrounding the anus;
often associated with irritation and burning
11 - 54
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Pyloric Stenosis and Ulcerative Colitis

Pyloric stenosis


A narrowing of the pyloric sphincter muscle;
interferes with the emptying of the stomach
Ulcerative colitis

An often chronic inflammatory disease that
affects the mucosa of the colon, beginning in
the sigmoid colon and extending upward into
the whole colon
11 - 55
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Unit Summary


List the organs, in order, of the GI tract
through which food passes.
Why is the duodenum vital to digestion?
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