Chapter 1 digestive system

Digestive System
• provides the nutrients needed by the body
 Ingestion - intake of food
 Mastication - the process of chewing
 Deglutition - swallowing
Peristalsis - wavelike movement that propels the food
 Digestion - breakdown of food
 Absorption - extracting nutrients
 Elimination - removal of waste products

Oral Cavity
• Mechanically breaks down the food through
mastication
• Lubricates the food to ease deglutition (a.k.a.
swallowing

Salivary Glands
• Moistens the food
• Produce salivary amylase (enzyme) to digest carbohydrates
1. Parotid - located near the ear
2. Submandibular - located under the lower jaw
3. Sublingual - located under the tongue

Teeth
• Breaks the food into small pieces
• Consists of
crown
root
• Attached to the gums through the root

Kinds of Teeth
1. Incisor - cut the food; located anteriorly
2. Cuspid - tear the food; located antero-laterally
3. Pre-Molar - Grinds the food; located laterally
4. Molar -Grinds the food; located postero-laterally

Pharynx
• Tube that connects the oral cavity to esophagus
1. Nasopharynx - most superior part located behind the nasal cavity
2. Oropharynx - located adjacent to the oral cavity
3. Hypopharynx - located below the oropharynx

Esophagus
• muscular, mucus-lined tube that
connects the throat to the stomach
• Has a sphincter at the end to
permit passage of food towards the
stomach (Lower Esophageal
Sphincter, Gastroesophageal
Sphincter, Cardiac Sphincter)
• Sphincter - a ringlike muscle that
serves as entrance or exit body
fluids or materials

Stomach
• expandable saclike
vessel located between
the esophagus and the
small intestines
3 Main Functions:
1. Begins the process chemical
digestion of protein by
gastric acids (hydrochloric
acid) and enzymes. [Food
mixed with gastric juices
and enzymes is called
chyme]
2. Aid in the mechanical
digestion of the food
3. Move the chyme to the
small intestine

Stomach
3 Main Sections
1. Fundus - area of the stomach that abuts the diaphragm
2. Body (a.k.a. Corporis) - central part of the stomach
3. Pylorus (a.k.a. gastric antrum) - distal end of the stomach, where the small
intestine begins
Cardia - portion of the stomach that surrounds the esophagogastric connection (so
named because of its proximity to the heart).

Stomach
• Rugae - the appearance of the stomach being lined with many
ridges or wrinkles.

Small Intestine
• Absorbs digested proteins, carbohydrates, and fats
1. Duodenum - “C” shaped structure lying adjacent to the stomach
2. Jejunum - involve in magnesium absorption
3. Ileum - contains Peyer’s patches for immunity; involve in vitamin
B12 absorption

Duodenum
1. Superior
2. Descending
3. Horizontal
4. Ascending

• Eliminates waste products from the body
• Involve in vitamin K synthesis through the help of normal
colonic bacteria
• Involve in water re-absorption
Large Intestine

Large Intestine
• Ileocecal Valve - junction between the small and the large
intestine.
• Cecum - the first part of the large intestine
• Vermiform appendix - wormlike structure in the cecum
[appendicitis, appendectomy]

Large Intestine
Parts of the Colon
• Ascending
• Hepatic Flexure
• Transverse
• Splenic Flexure
• Descending
• Sigmoid
• Rectum - held the feces
temporarily before
elimination

Anus
Internal & External Sphincter - guards the exit of the feces
Defecation - the process of releasing the feces from the body
(a.k.a. Bowel movement)

Accessory Organs
1. Liver
2. Gallbladder
3. Pancreas

Liver
• Divided into 3 lobes: Right, Left & Caudate
• Manufacture bile, which emulsifies, or mechanically breaks down,
fats into smaller particles so that they can be chemically digested
• Bile is composed of bilirubin, the waste product formed by the
normal breakdown of hemoglobin and cholesterol

Gallbladder
• small sac for storage of bile found on the
underside of the right lobe of the liver

Pancreas
• Located in the upper left quadrant
• Involve in the digestion of carbohydrates, proteins, and lipids
• Produces pancreatic enzymes such as pancreatic amylase [digest
carbohydrates], pancreatic lipase [digest fats], and carboxypeptidase
[digest proteins]

Pancreas
• Head
• Neck
• Body
• Tail

Pancreas
• Ampulla of Vater - regulates the release of bile and pancreatic
enzymes
• Sphincter of Oddi - controls the introduction of bile and
pancreatic secretions into the duodenum
Ampulla of Vater
Sphincter of Oddi

Peritoneum
• Forms the lining of the abdominal cavity
• Outer layer is called parietal peritoneum
• Inner layer is called visceral peritoneum

Omentum
 Folds of peritoneum that connects the abdominal organs to each other
or to the abdominal wall
1. Lesser Omentum - attached to the lesser curvature of the stomach and
the liver (a.k.a. Gastrohepatic Omentum)
2. Greater Omentum - hangs from the greater curvature of the stomach
and loops down in front of the intestine (a.k.a. Gastrocolic Omentum)

Medical Terminology related to
Digestive System
Ascites – excessive intraperitoneal fluid

Digestive System
Diarrhea = Abnormal discharge of watery,
semisolid stools

Digestive System
Dysphagia = Difficulty with swallowing that may
be due to an obstruction or spasm.

Digestive System
Eructation = Release of air from the stomach through
the mouth. Eructation may be caused by rapid
eating or by intentionally or unintentionally
swallowing air (aerophagia). Also called
burping or belching.

Digestive System
Flatulence = Gas expelled through the anus.
Also called flatus.

Digestive System
Gastralgia = Abdominal pain. Also called
gastrodynia.

Digestive System
Hepatomegaly = Enlargement of the liver.

Digestive System
Jaundice = Yellowing of the skin and sclerae
(whites of the eyes) caused by elevated
levels of bilirubin. Also called icterus.

Digestive System
Nausea = Sensation that accompanies the
urge to vomit but does not always lead
to vomiting.

Digestive System
Pyrosis = Painful burning sensation in esophagus, usually
caused by reflux of stomach contents,
hyperactivity, or peptic ulcer. Also known as
heartburn

Digestive System
Vomiting = Forcible or involuntary emptying of
the stomach through the mouth. The
material expelled is called vomitus or
emesis.

Digestive System
Ankyloglossia = An inability to move the tongue freely as a result
of a congenital shortened frenulum. Also referred to
as being “tongue-tied”.

Digestive System

Digestive System
cleft palate = Failure of the palate to close during embryonic
development, creating an opening in the roof of the
mouth. Cleft palate often is accompanied by a cleft lip.

Digestive System
Esophageal atresia = Esophagus that ends in a blind pouch
and therefore lacks an opening into the
stomach.

Digestive System
Gastroschisis = A congenital opening in the anterior
abdominal wall.

Digestive System
Hirschsprung’s disease = Congenital absence of normal nervous
function in part of the colon, which results in an absence of
peristaltic movement, accumulation of feces, and an
enlarged colon. Also called congenital megacolon

Digestive System
Omphalocele = A congenital herniation at the umbilicus.
Also called exomphalos.

Digestive System
pyloric stenosis = Condition in which the muscle between
the stomach and the small intestine narrows
or fails to open adequately to allow partially
digested food into the duodenum.

Digestive System
Anodontia = Either complete or partial lack of teeth. Also
referred to as edentulous.

Digestive System
aphthous stomatitis = Recurring condition characterized by small
erosions (ulcers), which appear on the mucous
membranes of the mouth. Also called a canker sore.

Digestive System
Cheilitis = Inflammation of the lips.

Digestive System
dental caries = Plaque disease caused by an interaction
between food and bacteria in the mouth, leading to
tooth decay. Also called cavities.

Digestive System
Glossitis = Inflammation of the tongue.

Digestive System
oral mucositis = Inflammation of the mucous
membranes of the mouth. Gastrointestinal
mucositis may be an adverse effect of
chemotherapy and can occur throughout
the GI tract.

Digestive System
oral leukoplakia = Condition of white patches that may
appear on the lips and buccal mucosa. It usually is
associated with tobacco use and may be
precancerous.

Digestive System
Ptyalism = Condition of excessive salivation.

Digestive System
Sialoadenitis = inflammation of a salivary gland.

Digestive System
Sialolithiasis = Condition of stones in a salivary gland or
duct.

Digestive System
Achalasia = Impairment of esophageal peristalsis along with the lower
esophageal sphincter’s inability to relax. Also called cardiospasm,
esophageal aperistalsis, and megaesophagus.

Digestive System
Esophagitis = Inflammation of the esophagus.
Gastritis = Acute or chronic inflammation of the stomach that may
be accompanied by anorexia (lack of
appetite),nausea, and vomiting, or indigestion.

Digestive System
Gastroesophageal reflux disease (GERD)
= Flowing back, or return, of the contents of the
stomach to the esophagus caused by an inability of the
lower esophageal sphincter (LES) to contract normally;
characterized by pyrosis with or without regurgitation of
stomach contents to the mouth.

Digestive System
peptic ulcer disease (PUD) = An erosion of the protective
mucosal lining of the stomach or
duodenum. Also called a gastric or
duodenal ulcer, depending on the site.

Digestive System
Appendicitis = Inflammation of the vermiform appendix.
May be acute or chronic, with or without
peritonitis.

Digestive System
hiatal hernia = Protrusion of a portion of the stomach
through the diaphragm. Also known as a
diaphragmatic hernia and diaphragmatocele.

Digestive System
Crohn’s disease = Inflammation of the ileum or the colon that is of
idiopathic origin
ulcerative colitis = Chronic inflammation of the colon and rectum
manifesting with bouts of profuse, watery
diarrhea.

Digestive System
anal fissure = Cracklike lesion of the skin around the anus.

Digestive System
anorectal abscess = Circumscribed area of inflammation in
the anus or rectum, containing pus.

Digestive System
Diverticulosis = Development of diverticula, pouches
in the lining of the intestines both large and small.
Diverticulitis = Inflammation occurring secondary to the
occurrence of diverticulosis.

Digestive System
Ileus = Obstruction. Paralytic ileus is lack of peristaltic movement in
the intestinal tract. Also called adynamic ileus

Digestive System
Intussusception = Inward telescoping of the intestines.

Digestive System
polyp of colon = Benign growth on the mucous membrane
of large intestine.

Digestive System
Proctitis = Inflammation of the rectum and anus. Also
called rectitis.

Digestive System
Proctoptosis = Prolapse of the rectum outside of the
anus.

Digestive System
Volvulus = Twisting of the intestine.

Digestive System
Cirrhosis = Chronic degenerative disease of the liver, commonly
associated with alcohol abuse, chronic liver disease, and
biliary tract disorders.

Digestive System
Cholangitis = Inflammation of the bile vessels.

Digestive System
Cholecystitis = Inflammation of the gallbladder, either
acute or chronic. May be caused by
choledocholithiasis or cholelithiasis.

Digestive System
Choledocholithiasis = Presence of stones in the common bile
duct.
Cholelithiasis = Presence of stones (calculi) in the gallbladder,
sometimes characterized by right upper quadrant
pain (biliary colic) with nausea and vomiting.

Chapter 1 digestive system

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Chapter 1 digestive system