Download Diapositiva 1

Digestive Tract
Some Definitions
• Enzymes-proteins that help control a
biochemical reaction
• Gland-an organ that produces
specific enzymes or hormones
• Duct-a type of tube
• Gastric-related to the stomach
• Metabolism-breaking down big
molecules into smaller molecules
• Pathology-study of the
characteristics, causes, and effects
of diseases
Oral Cavity
Oral Cavity Functions
• Teeth help break food into smaller
pieces
• Tongue helps form bolus of food
• Salivary glands provide moisture
for the bolus
• Salivary glands produce an
enzyme (amylase) to start
breaking down starch into sugars
Tongue Pathologies
•
•
•
•
•
•
Hairy Tongue
Geographical Tongue
Leukoplakia
Glossodynia
Painful papillae
Yellow Tongue
Hairy Tongue
Leukoplakia of the Tongue
Glossodynia of the Tongue
Salivary Gland Pathologies
• Salivary gland infections
• Salivary gland stones
• Salivary gland tumors
Pharynx
• Initial point of entry for the
bolus of food
• Epiglottis prevents food from
going down the respiratory
tract (trachea).
Location of Pharynx
Pharynx
Epiglottis
Location of the Esophagus
Esophageal Functions
• Pathway for the bolus into the
stomach
• Very muscular to help food get
into the stomach
• Esophagus moves in waves
(peristaltic action) to force bolus
downward
Esophageal Pathologies
• Gastroesophageal reflux
disease (GERD)
• Heartburn
• Esophageal cancer
Esophageal Cancer
Cancer
Stomach
• Storage site for ingested food
(bolus)
• Produces acid and gastric enzymes
• Entry and exit of stomach is
controlled by sphincters (cardiac
on top and pyloric on bottom)
• Very muscular gland to help mix
and break up bolus
• Action of acid and enzymes convert
bolus in chyme
Stomach
Stomach (Gastric) Pathologies
•
•
•
•
•
Indigestion
Heartburn
Peptic ulcers
GERD
Gastric tumors
Early Gastric Tumor
Small Intestine
• Comprised of duodenum,
jejunum, and ileum
• Duodenum contains the entry
site for the bile duct and
pancreatic duct
• Proteins, Fats, and
Carbohydrates are metabolized
in the small intestine
Small Intestine (cont.)
• Proteins are broken down into
peptides and amino acids
• Fats are broken down into fatty
acids and glycerol
• Carbohydrates are broken down
into simple sugars
• Harmful acid from the stomach
is neutralized by bicarbonate in
the small intestine
Small Intestine (cont.)
• Fine capillaries are found in
structures called the microvilli
which allow absorption of
nutrients into the blood stream
• Some water is also absorbed
by the small intestine
Small Intestine Components
Small Intestine Pathologies
•
•
•
•
•
•
•
•
Bleeding
Celiac disease
Crohn's disease
Infections
Intestinal cancers
Intestinal obstructions
Irritable bowel syndrome
Peptic ulcers
Crohn’s Disease
Cancer of the Small Intestine
Peptic Ulcer
Ulcer
Large Intestine
• Comprised of cecum, ascending
colon, transverse colon,
descending colon, sigmoid
colon, and rectum
• Major site for reabsorption of
water
• Majority of food metabolism has
occurred
Large Intestine (cont.)
• Possibly up to 700 different species
of “normal” bacteria occupy the
large intestine
• Normal bacteria help break down
some undigested food into smaller
molecules as well as gas formation
(carbon dioxide and nitrogen and
some methane, hydrogen sulfide,
and hydrogen
Large Intestine Components
Large Intestine Pathologies
•
•
•
•
•
•
•
•
•
•
Constipation
Diarrhea
Celiac disease
Colon polyps
Diverticulitis
Irritable bowel syndrome
Intestinal parasites
Lactose intolerance
Ulcerative colitis
Appendicitis
Colon Polyps
Diverticulitis
Ulcerative Colitis
Appendicitis
Liver
• Large organ comprised of four
lobes
• Large amount of blood flow
throughout this organ
• Controls both metabolic (larger
to smaller molecules and
anabolic reactions (smaller to
larger molecules
Liver Biochemical Reactions
•
•
•
•
•
•
•
•
•
•
•
•
•
Amino acid synthesis
Carbohydrate metabolism
Cholesterol synthesis
Lipogenesis (making of fats)
Synthesis of blood clotting factors
Makes red blood cells (in the fetus)
Bile synthesis (emulsifies fats)
Makes many enzymes and hormones
Breaks down hemoglobin (makes pigment
in bile)
Converts ammonia to urea (to be excreted
in the urine)
Makes albumin for blood serum
Stores vitamins and minerals
Alters toxicity of chemicals (e.g., drug
metabolism)
Liver
Liver Pathologies
•
•
•
•
•
•
Liver cancer
Cirrhosis of the liver
Jaundice
Hepatitis
Liver parasites
Variety of metabolic disorders
Liver Cancer
Cirrhosis of the Liver
Liver Parasites (E. histolytica)
Abscess
Gall Bladder
• Stores the bile that is made in the
liver
• Bile is introduced into the small
intestine (duodenum) by the
common bile duct
• Bile contains biliary salts that
emulsify fats (make them more
soluble in water; can be used as
detergents)
• Many of the bile chemicals are
pigmented and add color to the
content of the small and large
intestines)
Gall Bladder
Bile Duct
Gall Bladder
Gall Bladder Pathologies
• Gall stones
• Spastic bile duct
• Gall bladder cancers
Gall Stones
Stones
Pancreas
• Produces both digestive enzymes and
hormones
• Pancreatic hormones include insulin
(removes glucose) and glucagon (releases
glucose)
• Insulin is made in specialized cells called
the islets of Langerhans
• Releases pancreatic juice which is a
mixture of enzymes that breaks down the
proteins, fats, and carbohydrates in the
chyme
• Pancreatic juice travels from the pancreas
through the pancreatic duct into the
duodenum of the small intestine
Location of Pancreas
Pancreatic Pathologies
• Pancreatitis
• Pancreatic cancer
• Diabetes
Pancreatic Cancer
Cancer
The End of the Digestive Tract