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Case Study: A stomach cancer patient that had a feeding tube inserted asks…
Case Study:
A
stomach cancer
patient that had a
feeding tube
inserted asks how this will affect his diet & digestive process.
Background
The Digestive System
Alimentary canal (AKA GI tract)
The continuous tube from the mouth -> anus
Organs
Mouth
4 Digestive processes involved
Function
Swallowing initiates propulsion
Ingests
Some chemical digestion w/ carbs
Mechanical breakdown begins
Pharynx
Fun: Sevres to allow food passage down
oropharynx -> laryngopharynx
Esophagus
Fun: Muscular tube to get food -> stomach
Tissue
Nonkeratinized Stratified squamous
At esophagus-stomach junction
Simple columnar
Muscularis externa
Mixture of
Skeletal
Smooth
Fibrous adventitia
instead of serosa
Composed of
connective tissue
(allows bending)
Stomach
Functions
Digestive processes
Digestion
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Mechanical breakdown
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Propulsion
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Absorption
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Uses acid to kill bacteria
After food is stored, its -> chyme -> Small intestine
Sections involved
Cardiac sphincter
Fundus
Cardia
Body
Pyloric sphincter
Lumen
Rugae
Pyloric canal
Pyloric atrium
Tissue
Simple columnar
Contains
Gastric pits
Lead to gastric glands that produce
gastric juice
Cells
in fundus & body
Parietal cells (Fuzzy pitchforks)
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Chief cells
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Enteroendocrine cells
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Mucosal barrier
3 factors that create it
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Small intestine
Main functions
Chemical digestion
Swallowed contents turn into chyme
Absorption
Motility
Segmentation
Peristalsis
Tissue
Simple columnar
Contains 3 subsections
Jejunum (intraperitoneal)
ileum (intraperitoneal)
Duodenum
Mostly retroperitoneal
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illeocecal sphincter
Contains
Circular folds
Deep folds of mucosa & submucosa
Villi
Fingerlike projections of mucosa
Specialized for absorption
5 cells found here
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Microvilli
Have a small fuzzy appearence
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Large intestine
Function
Absorb much of remaining H2O
To prevent dehydration
Bacteria help digest things that haven't been broken down
To allow for more vitamin absorption
Store residues temp. & eliminate them
Mostly retroperitoneal
Motility
Haustral contractions occur
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Involves
Ascending colon
Hepatic flexure
Cecum
& Appendix
Transverse colon
Spleenic flexure
Descending colon
Rectum
Internal & external sphincters
Anus
Other features
Haustrum
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Epiploic appendages
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Tissue
Simple columnar
Stratified squamous (anal area)
GI track has 4 layers & is usually surrounded by peritoneum
Visceral peritoneum
Covers external surfaces
Parietal peritoneum
Lines body wall
Mesentery
Contains
Double membrane peritoneum
2 Serous membranes fused
Function
Provide routes for
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Hold organs in place
Store fat
Alimentary organs
NOT suspended by mesentery
Retroperitoneal
Lost their mesentary during development
Most of pancreas
Duodenum
Parts of large intestine
They have both adventitia & serosa
Intraperitoneal
or peritoneal organs
Def: Organs that keep their mesentary yet remain in peritoneal cavity
Such as stomach
Structures of alimentary canal
The 4 Tunics of GI tract (Ess. # 3)
1) Mucosa
Innermost mucous (epithelial) membrane
Lines lumen from mouth -> anus
It is an ENDOCRINE organ & part of digestive sys.
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Sub-layers
Epithelium
Simple columnar
Lamina propria
Loose areolar connective
Capillaries nourish epithelium
Muscularis mucosae
Enhance absorption & secretion
2) Submucosa
Areolar connective
Rich w/ nerves, blood & lymphatic VESSELS
Elastic fibers allow stomach to regain shape after meal
Much
ABSORPTION
occurs
3) Muscularis Externa
Composed of
Circular layer
Inner layer & form sphincters
Longitudinal layer
Outer layer
Responsible for
SEGMENTATION
&
PERISTALSIS
4) Serosa
Outermost layer of the intraperitoneal organs
Its the visceral peritoneum
Composed of
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In the esophagus, serosa is replaced w/
adventitia
Ordinary dense connective that binds esophagus -> surrounding structures
Blood supply -> alimentary canal
2 Main pathways
Splanchnic circulation
Supply from
aorta -> Digestive organs
This feeds digestive organs & the
hepatic portal circulation
nutrients & O2
Hepatic portal circulation
Blood from
aorta goes out -> stomach -> liver
, intestines, & spleen (celiac truck)
This blood then picks up nutrients
& Is sent to the
liver to "BREAK toxic chemical into less toxic chemicals"
Has lots of enzymes to act on things in blood after absorbing nutrients
This sys. helps to
keep you from getting intoxified
The GI tracts NS
Stimuli & controls of the digestive sys.
Enteric NS (Gut brain)
Contains enteric neurons
Consists of 2 intrinsic nerve plexuses
Submucosal nerve plexus
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Function
Monitors what is going through digestive sys. whether full or empty
& Makes its own decisions
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Causes of Digestive sys. activation
Mechanical & chemical stimulation
Effectors of this activity are
Glands
Secrete the acids & enzymes
Smooth muscles
Mix lumen contents to move contents
Rec. respond -> stimuli such as
Stretching of stomach
Changes in pH
All controlled by the NS
Intrinsic neurons
Short reflexes
from the
gut brain
Extrinsic neurons
Long reflexes
controlled by
brain
Hormonal controls
Hormones that activate the digestive tract
Motilin
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Secreton
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Ghrelin
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Accessory digestive system
Include
Gallbladder
Stores bile & concentrates it by absorption of some of its H2O & ions
Salivary glands
Submandibular
Below jar
Sublingual
Below tongue
Parotid
On cheeks
Tongue
Liver
Creates bile (To emulsify fats)
In order to mix w/ H2O
So it can be absorbed
Does
NOT FILTER ANYTHING
!!!
Largest gland in body
Teeth
Pancreas
Endocrine function
To release insulin & glucagon
Has many endocrines glands called
pancreatic ISLETS
Exocrine function
Digestive function
Most is retroperitoneal
Supplies most of the enzymes that digest chyme & bicarbonate (neutralizes stomach acid)
Contains
Acini
Clusters of secretory acinar cells
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Ducts
A system of ducts that transports the secretions
Functions
Digests food
Absorbs fragments through lining into blood
Including 6 activities
Mechanical breakdown
Increases surface area of ingested food
Includes
Chewing
Churning in stomach
Segmentation in small intestine
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Digestion
Catabolic process where enzymes secreted in lumen break down food ->
chemical building blocks
Propulsion
Moves the food through
Includes
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Absorption
Passage of digested end products from lumen w/ vits, minerals, & H2O ->
mucosal cells by transport ->
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Ingestion
Taking food in
Defecation
Eliminates indigestible substances
Enzymes Responsible for Digestion
Nutrients
Carbohydrates
Enzymes
Salivary
amylase
Location: Mouth
Pancreatic
amylase
Location: Duodenum
Proteins
Enzymes
Proteases
Examples
Pepsin
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Pancreatic enzymes
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Lipids
Enzymes
Lingual
lipase
Location: Mouth
Gastric
lipase
Location: Stomach
Pancreatic
lipases
Hepatopancreatic sphincter -> Duodenum
Nucleic acid
No nutritional value here
Basic Nutrients the Body Requires
Macronutrients
Carbs
Uses in body
The mono, C6H12O6, is used for fuel
Any C6H12O6 left, is -> glycogen or fat
Recommended intake
45-65% of calorie intake
W/whole grains & veggies
Lipids
Such as
Saturated
Meat
Dairy foods
Unsaturated
Seeds
Nuts
Olive & veggie oils
2
ESSENTIAL fatty
acids the liver cannot produce
Linoleic acid
Omega-6
Linolenic acid
Omega-3
Proteins
Eggs, milk, & most meats are
complete proteins
Nitrogen balance
(-) nitrogen balance
Protein breakdown exceeds amount being produced
(+) nitrogen balance
Rate protein synthesis = Rate protein breakdown
Essential amino acids
Phenylalanine
Leucine
Threonine
Isoleucine
Valine
Lysine
Methionine
Histidine (infants)
Tryptophan
Arginine (infants)
Micronutrients
Vitamins
They are
organic compounds
Without vits. all carbs, fats, & proteins would be useless
Most are coenzymes (act w/an enzyme)
They are either
Water soluble
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Fat soluble
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Minerals
Body requires moderate amounts of 7 minerals
S
Na+
K+
Cl-
P
Mg2+
Ca2+
Trace amounts of 12 others
Minerals make up ~ 4% body weight
Mineral rich foods
Veggies
Milk & some meats
Legumes
They are like vits. NOT used as a fuel, yet work w/other nutrients to ensure body functioning
Ex: NaCl are important electrolytes in blood
Upstream Effects
Indirect
Nutrients necessary for patient's feeding tube
Why
Lipids
are essential to diet
Prostaglandins
Regulatory moles which are involved in
Smooth muscle contraction
Blood pressure
Inflammation
Triglycerides
Fuel for skeletal muscle & hepatocytes
Fats help body absorb fat-soluble vitamins
Phospholipids
Important for myelin sheaths & cell membranes
Fat deposits in adipose
Provides
Protective cushioning around the bodies organs
Stored energy
Cholesterol
Precursor from which bile salts, steroid hormones, & other molecs are formed
Stabilizing component for plasma membranes
Recommended intake
20-35%
of total calorie intake
He should consume unsaturated fats
Such as
Dairy products
Soy
Eggs
Why
Carbs
are essential to diet
Many cells use fats from these nutrients as an energy source
Neurons & red blood cells rely the most on C6H12O6
A temp. shortage of blood-C6H12O6
Can lead to
Neuron death
Severely cause brain damage
Recommended intake
45-65%
of total calorie intake
Types
Complex carbs
Veggies
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Whole grains
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Why
Proteins
are essential to diet
Uses in the body
Important for
Collagen & elastin in connective tissue
Muscle
Enzymes
Hormones
Keratin in skin
Recommended intake
0.8 g
per kilogram of weight
Depending on whether the patient is in
(+) nitrogen balance
Examples
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Micronutrients needed
Vitamins
Water-soluble
B1
B2
B3
B5
B6
B7
B9
B12
Vit C
Fat-soluble
Vit A
Vit D
Vit E
Vit K
These are absorbed w/other lipids
Its
vital
the patient has
vitamins in his diet
b/c
Vit are coenzymes
W/out
vit. all
carbs, proteins & fats are useless
Minerals
Recommended intake
Greater than 200mg per day
K
Nerve function & acid-base balance
Cl
Osmotic balance
S
Component of certain aminos
Na
Blood pressure, H2O balance
P
Bone, Acid-base balance
Mg
ATP bioenergetics
Ca
For bone, blood clotting, & nerve function
These along w/
trace amounts
such as Fe, F, Zn. Cu, Mn, I, Co, Se, Cr, & Mo should be taken in addition
Important
for patient to have in diet
B/c
minerals are synergistic w/ other nutrients
to ensure proper body functioning
Direct
Events unable to take place in patient's digestive sys.
1)
Unable to ingest
food through the
mouth
2) Being that
swallowing initiates propulsion
, this is possibly
slowed
Propulsion
of the esophagus does not take place
Halted
peristalsis
of
Esophagus
Duodenum
Stomach
3)
Mechanical breakdown
does not occur in the mouth, stomach, and duodenum
Depending on the precise location of the feeding tube, there is a possibility that
segmentation
of the
jejunum & ileum
may occur
Being that food is bypassing the stomach & duodenum (Main site of enzymatic release) The
liver
may
not produce bile
in the usual way
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Being that
HCl
is not present due to the bypass, the
food he can take into the tube should be mostly soft
Salivary glands
Such as
Parotid gland
is not secreting as much ions, enzymes, & mucin
No
salivary amylase
is secreted
For the catabolism of carbs
Upstream Causes
Direct
Feeding tube
was placed in the
alimentary canal
of an
elderly male
He also had his
gall bladder removed
Indirect
Possible reasons for patients digestive issues
Not maintaining a
healthy diet
throughout his life
This could possibly contribute to
gut imbalances
This can cause
long-term inflammation
in the stomach
Especially if there was an increase in the
H. Pylori bacteria
The bacteria
destroy the mucosal layer
Potentially leading to
gastric cancer
Gastric ulcers
could further disrupt the stomachs mucosal layer
Family history
of the cancer
Severe
anxiety
#
Constant
smoking
Working w/
harmful chemicals
*Organs, chemicals, & enzymes
unable to participate in the digestive process*
Stomach
Caridia
Fundus
Body
Pyloric sphincter
Lumen
Rugae
Pyloric atrium
Pyloric canal
Enzymes involved
CCK
Inhibits stomach's secretory activity
Gastrin
Increases HCl secretion
Histamine
Activates parietal cells to release HCl
Secretin
Inhibits gland secretion & motility
Somatostatin
Inhibs gastric secretion of ALL products
Small intestine
Duodenum
Enzymes involved
Eneropeptidase
Activates trypsinogen -> Trypsin
Activating carboxypeptidase & chymotrypsin
Gastrin
Stimulates peristalsis
Somatostatin
Inhibits GI flow, inhibiting absorption
Vasoactive intestinal peptide (VIP)
Stimulates buffer secretion
Relaxes smooth muscle
Motilin
Stimulates smooth muscle contractions
Esophagus
Cariac sphincter
Mouth
Pharynx
Oropharynx
Laryngopharynx
Liver
Enzymes involved
#
Cholecystokinin (CCK)
Potentiates secretin's actions
Secretin
Increases bile output
Pancreas
Pancreatic juice
Such as
proenzymes
(Secretions of acini cells transported by ducts)
Which contain
inactive enzymes
Other enzymes
Pancreatic
Proteases
Lipases
Amylase
Nuceases
Somatostatin
Inhibits secretion
Secretin
Increases pancreatic juice output
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Gall bladder
Enzymes involved
Somatostatin
Inhibits contraction & bile release
Cholecystokinin (CCK)
Stimulates organ to contract & expel stored bile
Secretin
Increases bile output