Transcript Chapter 25 Digestive system infections

Chapter 25
Digestive system infections
Medgar Evers College, CUNY
Bio 261
Prof. Santos
Basic anatomy of the human
digestive system
Salivary
glands
Salivary
glands
Cardiac
orifice
Tongue
Oral cavity
Parotid gland
Sublingual gland
Mouth
Pharynx
Submandibular gland
Esophagus
Esophagus
Pyloric
sphincter
Liver
Ascending
portion of
large intestine
Stomach
Gallbladder
Gallbladder
Liver
Pancreas
Small intestine
Duodenum of
small intestine
Large intestine
Rectum
Cecum
Small
intestines
Pancreas
IIeum
of small
intestine
Appendix
Stomach
Anus
Large
intestines
Rectum
Anus
A schematic diagram of
the human digestive system
• Food is pushed along the digestive tract
by peristalsis
– Rhythmic waves of contraction of smooth
muscles in the wall of the canal
• In the oral cavity, food is lubricated and
digestion begins
– And teeth chew food into smaller particles that
are exposed to salivary amylase, initiating the
breakdown of glucose polymers
• The region we call our throat is the
pharynx
– A junction that opens to both the esophagus
and the windpipe (trachea)
• The esophagus
– Conducts food from the pharynx down to the
stomach by peristalsis
• The stomach stores food
– And secretes gastric juice, which converts a
meal to acid chyme
• Gastric juice
– Is made up of hydrochloric acid and the
enzyme pepsin
• The lining of the stomach
– Is coated with mucus, which prevents the
gastric juice from destroying the cells
• The small intestine
– Is the longest section of the alimentary canal
– Is the major organ of digestion and absorption
• The first portion of the small intestine is
the duodenum
– Where acid chyme from the stomach mixes
with digestive juices from the pancreas, liver,
gallbladder, and intestine itself
• The pancreas produces proteases,
protein-digesting enzymes
– That are activated once they enter the
duodenum
Pancreas
Membrane-bound
enteropeptidase
Inactive
trypsinogen
Other inactive
proteases
Lumen of duodenum
Trypsin
Active
proteases
• The small intestine has a huge surface
area
– Due to the presence of villi and microvilli that
are exposed to the intestinal lumen
• The enormous microvillar surface
– Is an adaptation that greatly increases the
rate of nutrient absorption
• The large intestine, or colon
– Is connected to the small intestine
• A major function of the colon
– Is to recover water that has entered the
alimentary canal
• The wastes of the digestive tract, the feces
– Become more solid as they move through the
colon
– Pass through the rectum and exit via the anus
Normal microbiota of the digestive
system
• Different species colonize the mouth
depending on their ability to attach to
specific receptors.
• Dental plaque consists of many bacteria of
different species attached to the teeth or
each other.
• Anaerobic bacteria are also present.
Bacterial infections of upper
digestive system
symptoms pathogene treatment
sis
Disease
Cause
Dental
caries or
tooth
decay
*incubation
Streptococcus Severe pain,
mutans
discoloration
period is 1 to
24 months
of tooth or
breakage
Glucan is
produced
from
sucrose.
This is
needed for
dental
caries
production
Restrict
sugar,
fluoride in
toothpaste
see
dentist
regularly
Bacterial infections of upper
digestive system
Disease
Cause
symptoms pathogene treatment
sis
Periodontal
disease
Dental plaque
Bleeding,
sensitive gums,
bad breath,
loosening of the
tooth,
Bacteria
produces
inflammatory
response,
plaque forms,
widens and
anaerobic
bacteria grow,
toxins and
enzymes
degrade tissue
Avoid buildup of
plaque and
surgery if
needed
Bacterial infections of upper
digestive system
symptoms pathogene treatment
sis
Disease
Cause
Trench
mouth
(acute
necrotizing
ulcerative
gingervitis)
A spirochete Fever,
of genus
painful
Treponema bleeding
gums, foul
mouth odor
Tissue
destruction,
ulceration
and tissue
invasion by
spirochete.
Antibiotic
treatment
Bacterial infections of upper
digestive system
Disease
Cause
Helicobacter H. pylori
pylori
gastritis
symptoms pathogene treatment
sis
Vomiting,
belching,
abdominal
pain and
tenderness
and bleeding
if ulcer or
cancer
associated
Pathogen
survives
acidity of
stomach,
penetrates
mucus,
inflammatory
response,
thinning of
mucus can
occur if ulcer
forms
Antibiotics
and
medication
to suppress
acid
formation
H. pylori
•
•
•
•
Gram –
Microaerophile
Multiple polar flagella for motility
Produces urease to neutralize acidity of
stomach
• Buries itself on the mucus layer to survive
Viral infections of upper digestive
system
Disease
Cause
symptoms pathogene treatment
sis
Herpes
HSV
Type 1
Fever,
sore
throat,
pain in
lip
followed
by
blisters
Virus
replicates in
the
epithelium,
an immune
response
follows, but
virus hides
in sensory
nerves
Anti viral
medicatio
n such as
acyclovir,
penciclovir
Viral infections of upper digestive
system
Disease
Cause
symptoms pathogene treatment
sis
Mumps
*incubation
period is 15
to 21 days
Mump virus
Fever,
headache,
loss of
appetite,
painful
swollen
parotid
glands,
painful
enlarged
testicles,
pelvic pain
in women
Virus
replicates in
the upper
respiratory
tract and
then travels
to parotid
glands,
inflammatory
response
occurs
An effective
attenuated
vaccine
since 1967
has been in
place since
then.
Bacterial infections of lower
digestive system
Disease
Cause
symptoms pathogene treatment
sis
Cholera
Vibrio
cholerea
Massive
diarrhea,
vomiting,
muscle
cramps
Exotoxins that
cause
excessive
excretion of
electrolytes by
the intestinal
epithelium;
leads to
dehydration
and shock
Purification of
water supply,
rehydration
with
electrolyte
and glucose
mumps
• Only one antigenic type of the mumps is
known.
Bacterial infections of lower
digestive system
Disease
Cause
symptoms pathogene treatment
sis
Shigellosis
Species of
shigella
Fever,
dysentery,
vomiting
headache,
stiff neck,
painful joints
Pathogen
invades and
multiplies
within the
intestinal
epithelium
Antibiotics
such as
ampicillin,
sanitary
measures,
Bacterial infections of upper
digestive system
Disease
Cause
symptoms pathogene treatment
sis
Gastroenteritis
E. coli
Vomiting
and
diarrhea,
sometimes
dysentery
(crampy
abdominal
pain and
bloody
diarrhea)
caused by
E.coli
Attachment,
toxins,
invasion of
intestinal
epithelium,
loss of
microvilli
Bismuth
compound
treatment,
sanitary
conditions,
replacement
of fluids loss
Bacterial infections of lower
digestive system
Disease
Cause
symptoms pathogene treatment
sis
Salmonellosis
Salmonella
enterica
Diarrhea,
vomiting,
Invasion and
penetration
of tissue,
inflammatory
response
No
treatment
unless
tissue
invasion
then
antimicrobial
agent
Bacterial infections of lower
digestive system
Disease
Cause
symptoms
pathogenesi
s
treatment
Campylobac
teriosis
Campylobacter
jejuni
Diarrhea,
fever,
abdominal
cramps,
nausea,
vomiting,
bloody stool
Low
infecting
dose,
pathogen
multiplies
within and
beneath the
epithelial
cells,
inflammatory
response
Sanitary
measures,
and no
antimicrobial
treatment
Viral infections of lower digestive
system
Disease
Cause
symptoms pathogene treatment
sis
Hepatitis A
(acute and
rarely leads
to long term
liver or
permanent
damage)
Nonenveloped
ss RNA picorna
virus
Fatigue, fever,
loss of appetite,
nausea, right
sided
abdominal pain,
dark colored
urine
Viral replication Inactivated
and damage
vaccine
restricted to
liver. How it
gets there is still
being
investigated
Viral infections of lower digestive
system
Disease
Cause
symptoms pathogene treatment
sis
Hepatitis B
Enveloped ds
DNA
hepadnavirus
More severe
than A,
progressive
liver damage,
can lead to
cirrhosis and
cancer
(infected
blood or
body
fliud/oral)
HBV is carried Combined
to liver by
Hepatitis A
bloodstream, and B vaccine
attaches and
invades liver
cells
Viral infections of lower digestive
system
Disease
Cause
symptoms pathogene treatment
sis
Hepatitis C
(most
commonly
transmitted
by sharing
needles)
Enveloped
ss RNA
flavivirus
Few or no
symptoms,
progressive
liver damage
or cancer in
10 to 20% of
cases
Liver cells
are infected
and
replication
occurs,
inflammatory
response
occurs
No vaccine
but one
should avoid
alcohol use
and anti viral
medication if
needed
2 other viral infections of the
lower
• 1- rotaviral gastroenteritis, most common
cause of viral gastroenteritis in children
and infants
• 2- noroviral gastroenteritis, most common
cause of viral gastroenteritis in the USA
Protozoan infections of lower
digestive system
Disease
Cause
symptoms pathogene treatment
sis
Giardiasis
Giardia
lamblia, a
pear shaped
protozoan
Flatulence,
nausea,
vomiting,
diarrhea,
abdominal
cramps,
weight loss
Host
immune
response to
attachment
of pathogen
to epithelial
lining
Antimicrobial
medications
such as
atabrine or
flagyl
Protozoan infections of lower
digestive system
Disease
Cause
symptoms pathogene treatment
sis
Cryptosporidiosis
Cryptosporidium
parvum
Fever, loss of
appetite, nausea,
crampy abdominal
pain, watery
diarrhea lasting 10
to 14 days
Invasion of
epithelial cells,
inflammatory
response
No effective
treatment exists
but sanitary
conditions should
be kept,
pasteurization of
beverages
Protozoan infections of lower
digestive system
Disease
Cause
symptoms pathogene treatment
sis
Cyclosporiasis
Cyclospora
cayetanensis
Fatigue, loss Very little is
of appetite,
known
vomiting,
watery
diarrhea,
weight loss
Bactrim,
Septra
antimicrobial
agents, boil
water before
drinking
Protozoan infections of lower
digestive system
Disease
Cause
symptoms pathogene treatment
sis
Amebiasis
Entamoeba
histolytica
Diarrhea,
abdominal
pain, blood in
feces
Ingested cysts Metronidazole
liberate the
or
pathogen,
paromomycin
reach large
intestine, feed
on mucus and
cells lining the
intestine, and
sometimes
they penetrate
the lining by
using
enzymes