Download Digestive System

Digestive System
Anatomy of the Digestive System
 GI tract (alimentary canal) = Continuous tube
running through the ventral body cavity, mouth to
anus
 Accessory structures, Teeth, Tongue, Salivary glands,
Liver, Gallbladder, Pancreas
Digestive Process
 Ingestion
 Movement = peristalsis
 Secretion ( water, HCI, buffers, enzymes)
 Digestion = process of breaking down large food
particles into molecules which are small enough to
enter body cells
 Mechanical digestion = chewing, churning, mixing
with secretions
Digestive Process
 Chemical digestion = series of catabolic (hydrolysis)
reactions that break down large carbohydrates, lipid,
& protein food particles into smaller molecules that
can be used by body cells
 Absorption = moving these nutrient molecules from
GI tract into blood / lymph
 Defecation = emptying of the rectum, to remove
indigestible substances
Digestive Process
 Mouth = buccal cavity
 Uvula = muscular process which hangs from the
back of the soft palate
 Tongue = forms the floor of the oral cavity
 Salivary glands
Digestive Process
 Saliva = continuous secreted into the mouth;
increased amount of saliva secreted with presence of
food in mouth / nervous stimulation, Lubricates;
keeps oral and pharyngeal membranes moist, Helps
to dissolve food, Starts chemical digestion of
carbohydrates (contains the enzyme amylase)
 3 pairs of major salivary glands: parotid,
submandibular, sublingual
Esophagus
 Esophagus = muscular tube behind the trachea;
connects pharynx to stomach
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Moves the bolus by peristalsis; NO chemical digestion
Esophagus contains upper and lower esophageal sphincters
Stomach
 Shaped like a “J” = stomach is just a wide place in
the GI tract
 4 main regions:
1.
2.
3.
4.
Cardia = Right uppermost; just past the lower esophageal
sphincter
Fundus = Left uppermost
Body = middle, curved portion of stomach
Pylorus = lower portion; attaches to the duodenum
 Lining of stomach contains folds (rugae), similar to
bladder lining
Stomach
 Gastric glands; located in gastric pits:
HCl, mucus
(protective),other enzymes
 Only a few substances are absorbed thru the stomach
wall:
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some water
Electrolytes
certain drugs (aspirin)
alcohol
Pancreas
 Posterior to lower stomach
 Pancreas is connected to duodenum by 2 ducts
(pancreatic & accessory)
 Tiny patches of cells (1%) = Secrete hormones, 99%
of pancreas cells = Secrete pancreatic juice:
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Pancreatic amylase → breaks down carbs
Trypsin, chymotrypsin, carboxypeptidase → digest proteins
Pancreatic lipase → digests fats
Ribonuclease & deoxyribonuclease → digest nucleic acids
Liver
 Liver = 2nd largest organ of the body
 Large right lobe + small left lobe (positioned behind
lower sternum), Produce bile → through a duct system
to gallbladder for storage, Gallbladder then secretes bile
when stimulated by nervess / hormones
 Functions of the Liver
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Carb metabolism
Lipid metabolism
Protein metabolism
Also convert one amino acid to another, as needed by the body
Liver removes & detoxifies certain drugs & hormones from the
blood
Liver stores vitamins (A, B12, D, E, K) and minerals (ferritin, Cu,
etc.)
Gallbladder
 Gallbladder stores & concentrates the bile
Small Intestines
 Small Intestines, Duodenum = top end; connected
to pyloric sphincter, Jejunum, Ileum = lower end;
connected to large intestine at ileocecal sphincter
 Small intestine is highly adapted for digestion &
absorption, Large surface area for absorption
 Absorption = passage of end products of digestion
from GI tract into blood or lymph (90% of
absorption occurs in the small intestine)
Large Intestines
 Large Intestine = Colon, Cecum = a blind pouch
about 2.5” long; hangs below the ileocecal sphincter,
Vermiform appendix = coiled tube attached to the
cecum; 3” long, Colon (4 parts)
 Rectum = anterior to the sacrum & coccyx; about
8” long, Anus = outer opening of the large intestine
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Internal anal sphincter = smooth muscle (involuntary)
External anal sphincter = skeletal muscle (voluntary)
 More water gets absorbed in the Colon (liquid
chyme → solid/semisolid feces)
Disorders and procedures of the digestive system
 Parotitis – mumps, swollen parotid salivary glands,
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bacterial
Heartburn – chyme pushed up esophagus due to
incomplete closure of the esophageal sphincter
Vomiting – noxious chemicals, disease, motion
Gall stones – cholesterol crystals formed in gall bladder
Colon cancer – rectal bleeding, anemia
Appendicitis – inflammation, peritonitis, shock, caused
by bacterial infection or fecolith
Diarrhea – speed bowel up
Disorders and procedures of the digestive system
 Constipation – slow bowel down
 Stomach ulcers – lack of mucous bacteria or Nsaids
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drugs creates a hole
Celiac disease – autoimmune, chronic diarrhea, fatigue,
failure to thrive in children
Cystic fibrosis – recessive genetic disease, chloride
channel not transported across membrane,
malabsorption in gut cannot exchange water, pancreas
does not make enzymes well
Appendectomy – cut off appendix
Cholecystectomy – cut off gall bladder
Disorders and procedures of the digestive system
 Endoscopy – sending fiber optic camera into esophagus
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to evaluate and band bleeding vessels
Colonoscopy – sending fiber optic camera into colon to
evaluate and take biopsy
Short gut syndrome – genetic abnormality short small
intestinal tract
Comb procedure – zipper cut the intestines to increase
length, fix short gut
Whipple – surgical removal of pancreatic cancer, attach
remaining pancreas to duodenum, attach stomach to
jejunum, duodenum become duct for pancreatic and liver
secretions
Crazy surgical options: 100lbs overweight, bmi of
40
 Lap band – plastic band around stomach that can be
tightened, removable surgically
 Gastric bypass – any rearranging or skipping of the
stomach or small intestines
 Roux-en-y – cut off most of stomach, attaches small
egg sized portion to the jejunum, caused
malabsorption
Healthy Diet
 A healthy diet is one that helps maintain or improve
general health. It is important for lowering many
chronic health risks, such as obesity, heart disease,
diabetes, hypertension and cancer. A healthy diet
involves consuming appropriate amounts of all
essential nutrients and an adequate amount of water.
Healthy Diet Nutrients can be obtained from many different
foods, so there are numerous diets that may be
considered healthy. A healthy diet needs to have a
balance of macronutrients (fats, proteins, and
carbohydrates), calories to support energy needs,
and micronutrients to meet the needs for human
nutrition without inducing toxicity or excessive
weight gain from consuming excessive amounts.
 Diet types gluten free, vegetarian, vegan, diabetes,
Atkins, south beach, lactose intolerant
Gluten Free
 A gluten-free diet is a diet that excludes foods
containing gluten. Gluten is a protein found in wheat
(including kamut and spelt), barley, rye, malts and
triticale. It is used as a food additive in the form of a
flavoring, stabilizing or thickening agent, often as
"dextrin". A gluten-free diet is the only medically
accepted treatment for celiac disease, the related
condition dermatitis herpetiformis, and wheat
allergy.
Gluten Free
 Additionally, a gluten-free diet may exclude oats.
Medical practitioners are divided on whether oats
are an allergen to celiac disease(chronic diarrhea and
failure to thrive) sufferers or if they are crosscontaminated in milling facilities by other allergens.
Gluten Free
 The term gluten-free is generally used to indicate a
supposed harmless level of gluten rather than a
complete absence. The exact level at which gluten is
harmless is uncertain and controversial. A recent
systematic review tentatively concluded that
consumption of less than 10 mg of gluten per day is
unlikely to cause histological abnormalities, although
it noted that few reliable studies had been done.
Gluten Free
 Regulation of the label gluten-free varies widely by
country. In the United States, the FDA issued
regulations in 2007 limiting the use of "gluten-free"
in food products to those with less than 20 ppm of
gluten.
Vegetarian and Vegan
 Vegetarianism encompasses the practice of following
plant-based diets (fruits, vegetables, etc.), with or
without the inclusion of dairy products or eggs, and
with the exclusion of meat (red meat, poultry, and
seafood). Abstention from by-products of animal
slaughter, such as animal-derived rennet and gelatin,
may also be practiced.
 Vegetarianism can be adopted for different reasons:
In addition to ethical reasons, motivations for
vegetarianism include health, religious, political,
environmental, cultural, aesthetic or economic.
Vegetarian and Vegan
 There are varieties of the diet as well: an ovo-
vegetarian diet includes eggs but not dairy products,
a lacto-vegetarian diet includes dairy products but
not eggs, and an ovo-lacto vegetarian diet includes
both eggs and dairy products. A vegan diet excludes
all animal products, including eggs, dairy, and
honey.
Diabetic Diet
 The basics to diabetic diet meal planning are simple
once we understand the way our body breaks down
food. Everything we eat is broken down into sugar
eventually. Sugary foods such as sweets or fruit hit
the bloodstream almost immediately, followed by the
slower starches (carbohydrates, or carbs), which take
an hour or two to break down depending on their
complexity.
Diabetic Diet
 Proteins are next, taking about four hours, then
between six and eight hours the fats finally break
down. If strict attention is paid to diet and exercise,
many diabetics can control their blood sugar with
minimal dependence on medication.
Atkin’s Diet
 The Atkins diet involves limited consumption of
carbohydrates to switch the body's metabolism from
metabolizing glucose as energy over to converting
stored body fat to energy. This process, called
ketosis, begins when insulin levels are low; in normal
humans, insulin is lowest when blood glucose levels
are low (mostly before eating).
Atkin’s Diet
 Ketosis lipolysis occurs when some of the lipid stored
in fat cells are transferred to the blood and are
thereby used for energy. On the other hand, caloric
carbohydrates (for example, glucose or starch, the
latter made of chains of glucose) impact the body by
increasing blood sugar after consumption. (In the
treatment of diabetes, blood sugar levels are used to
determine a patient's daily insulin requirements.)
Fiber, because of its low digestibility, provides little
or no food energy and does not significantly impact
glucose and insulin levels.
Atkin’s Diet
 The Atkins Diet restricts "net carbs" (digestible
carbohydrates that impact blood sugar). One effect is
a tendency to decrease the onset of hunger, perhaps
because of longer duration of digestion (fats and
proteins take longer to digest than carbohydrates).
Atkins states in his 2002 book New Diet Revolution
that hunger is the number one reason why low-fat
diets fail and that the Atkins diet is easier because
you are allowed to eat as much as you want
South Beach Diet
 According to Agatston, hunger cycles are triggered
not by carbohydrates in general, but by
carbohydrate-rich foods that the body digests
quickly, creating a spike in blood sugar. Such foods
include the heavily refined sugars and grains that
make up a large part of the typical Western diet. The
South Beach Diet eliminates these carbohydrate
sources in favor of relatively unprocessed foods such
as vegetables, beans, and whole grains. Carbohydrate
sources are considered "good" only if they have a low
glycemic index.
South Beach Diet
 Given that South Beach Diet was designed by a
cardiologist, it should be no surprise that it
eliminates trans-fats and discourages saturated fats.
Although foods rich in these "bad fats" do not
contribute to the hunger cycle, they do contribute to
LDL cholesterol and heart disease. The South Beach
Diet replaces them with foods rich in unsaturated
fats and omega-3 fatty acid which contribute to HDL
cholesterol and provide other health benefits.
Specifically, the diet excludes the fatty portions of
red meat and poultry, replacing them with lean
meats, nuts, and oily fish.
South Beach Diet
 Agatston divides the South Beach Diet into three phases,
each progressively becoming more liberal. "Phase 1" lasts
for the first two weeks of the diet. It eliminates all sugars,
processed carbohydrates, fruits, and some higherglycemic vegetables as well. Its purpose is to eliminate
the hunger cycle and is expected to result in significant
weight loss. "Phase 2" continues as long as the dieter
wishes to lose weight. It re-introduces most fruits and
vegetables and some whole grains as well. "Phase 3" is
the maintenance phase and lasts for life. There is no
specific list of permitted and prohibited foods. Instead,
the dieter is expected to understand the basic principles
of the diet and live by the principles
Lactose Intolerant
 Lactose intolerance, also called lactase deficiency or
hypolactasia, is the inability to digest and metabolize
lactose, a sugar found in milk. It is caused by a lack
of lactase, the enzyme required to break down
lactose in the digestive system, and results in
symptoms including abdominal pain, bloating,
flatulence, diarrhea, nausea and acid reflux.
Lactose Intolerant
 Most mammals normally become lactose intolerant
when they are young but some human populations
have developed lactase persistence, in which lactase
production continues into adulthood. It is estimated
that 75% of adults worldwide show some decrease in
lactase activity during adulthood. The frequency of
decreased lactase activity ranges from 5% in
northern Europe through 71% for Sicily to more than
90% in some African and Asian countries.
Lactose Intolerant
 Lactose is a water-soluble molecule. Therefore fat
percentage and the curdling process affect tolerance
of foods. After the curdling process lactose is found
in the water portion (along with whey and casein)
but not in the fat portion. Dairy products that are
"fat reduced" or "fat free" generally have a slightly
higher lactose percentage. Low fat dairy foods,
additionally, often have various dairy derivatives
such as milk solids added to them to enhance
sweetness, increasing the lactose content
Obesity Eating Disorders
 National Institute of Mental Health
 Eating disorders - An eating disorder is an illness
that causes serious disturbances to your everyday
diet, such as eating extremely small amounts of food
or severely overeating. A person with an eating
disorder may have started out just eating smaller or
larger amounts of food, but at some point, the urge
to eat less or more spiraled out of control. Severe
distress or concern about body weight or shape may
also characterize an eating disorder.
Obesity Eating Disorders
 Eating disorders frequently appear during the teen
years or young adulthood but may also develop
during childhood or later in life. Common eating
disorders include anorexia nervosa, bulimia nervosa,
and binge-eating disorder.
 Eating disorders are real, treatable medical illnesses.
They frequently coexist with other illnesses such as
depression, substance abuse, or anxiety disorders.
Anorexia
 Anorexia – Extreme thinness (emaciation)
 A relentless pursuit of thinness and unwillingness to
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maintain a normal or healthy weight
Intense fear of gaining weight
Distorted body image, a self-esteem that is heavily
influenced by perceptions of body weight and shape,
or a denial of the seriousness of low body weight
Lack of menstruation among girls and women
Extremely restricted eating.
Anorexia
 Many people with anorexia nervosa see themselves
as overweight, even when they are clearly
underweight. Eating, food, and weight control
become obsessions. People with anorexia nervosa
typically weigh themselves repeatedly, portion food
carefully, and eat very small quantities of only
certain foods. Some people with anorexia nervosa
may also engage in binge-eating followed by extreme
dieting, excessive exercise, self-induced vomiting,
and/or misuse of laxatives, diuretics, or enemas.
Anorexia
 Some who have anorexia nervosa recover
with treatment after only one episode.
Others get well but have relapses. Still
others have a more chronic, or long-lasting,
form of anorexia nervosa, in which their
health declines as they battle the illness.
Anorexia
 Other symptoms may develop over time, including:
 Thinning of the bones (osteopenia or osteoporosis)
 Brittle hair and nails
 Dry and yellowish skin
 Growth of fine hair all over the body (lanugo)
 Mild anemia and muscle wasting and weakness
 Severe constipation
 Low blood pressure, slowed breathing and pulse
 Damage to the structure and function of the heart
 Brain damage
 Multiorgan failure
 Drop in internal body temperature, causing a person to feel cold all the
time
 Lethargy, sluggishness, or feeling tired all the time
 Infertility
Bulimia
 Bulimia - Bulimia nervosa is characterized by
recurrent and frequent episodes of eating unusually
large amounts of food and feeling a lack of control
over these episodes. This binge-eating is followed by
behavior that compensates for the overeating such as
forced vomiting, excessive use of laxatives or
diuretics, fasting, excessive exercise, or a
combination of these behaviors.
Bulimia
 Unlike anorexia nervosa, people with bulimia
nervosa usually maintain what is considered a
healthy or normal weight, while some are slightly
overweight. But like people with anorexia nervosa,
they often fear gaining weight, want desperately to
lose weight, and are intensely unhappy with their
body size and shape. Usually, bulimic behavior is
done secretly because it is often accompanied by
feelings of disgust or shame. The binge-eating and
purging cycle happens anywhere from several times
a week to many times a day.
Bulimia
 Other symptoms include:
 Chronically inflamed and sore throat
 Swollen salivary glands in the neck and jaw area
 Worn tooth enamel, increasingly sensitive and decaying teeth
as a result of exposure to stomach acid
 Acid reflux disorder and other gastrointestinal problems
 Intestinal distress and irritation from laxative abuse
 Severe dehydration from purging of fluids
 Electrolyte imbalance (too low or too high levels of sodium,
calcium, potassium and other minerals) which can lead to
heart attack.
Binge Eating
 With binge-eating disorder a person loses control
over his or her eating. Unlike bulimia nervosa,
periods of binge-eating are not followed by purging,
excessive exercise, or fasting. As a result, people with
binge-eating disorder often are over-weight or obese.
People with binge-eating disorder who are obese are
at higher risk for developing cardiovascular disease
and high blood pressure. They also experience guilt,
shame, and distress about their binge-eating, which
can lead to more binge-eating.
Binge Eating
 Treatment - Adequate nutrition, reducing excessive exercise,
and stopping purging behaviors are the foundations of
treatment. Specific forms of psychotherapy, or talk therapy,
and medication are effective for many eating disorders.
However, in more chronic cases, specific treatments have not
yet been identified. Treatment plans often are tailored to
individual needs and may include one or more of the
following:
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Individual, group, and/or family psychotherapy
Medical care and monitoring
Nutritional counseling
Medications.
 Some patients may also need to be hospitalized to treat
problems caused by mal-nutrition or to ensure they eat
enough if they are very underweight.
Males
 Like females who have eating disorders, males also
have a distorted sense of body image. For some, their
symptoms are similar to those seen in females.
Others may have muscle dysmorphia, a type of
disorder that is characterized by an extreme concern
with becoming more muscular. Unlike girls with
eating disorders, who mostly want to lose weight,
some boys with muscle dysmorphia see themselves
as smaller than they really are and want to gain
weight or bulk up. Men and boys are more likely to
use steroids or other dangerous drugs to increase
muscle mass.
Males
 Although males with eating disorders exhibit the
same signs and symptoms as females, they are less
likely to be diagnosed with what is often considered a
female disorder. More research is needed to
understand the unique features of these disorders
among males.
 Metabolism – life period, exercise quantity, genetic
factors
 Obesity – evolutionarily designed to hold on to
calories and crave salty, sweet, greasy
 Thyroidism – hypothyroidism weight gain
Calorie Equation
 Recommended daily caloric intake equation:
 MALE: 105 lbs for first 5’, 6 lbs for every additional
inch of height, +/- 15 lbs for build = Ideal Weight
 FEMALE: 100 lbs for first 5’, 5 lbs for every
additional inch of height, +/- 15 lbs for build = Ideal
Weight
Calorie Use
 Caloric Use: average Ideal and Actual weights x 10 x
1.5 (sedentary) or 1.7 (exercise 3 days per week) or
2.0 (exercise every day) = Number of Calories you
burn each day
 1 lb of fat = 3,500 Cal; if you ingest 500 less Cal per
day you will lose 1 lb of fat per week
Substance Abuse
 Substance abuse, also known as drug abuse, refers to
a maladaptive pattern of use of a substance (drug)
that is not considered dependent. Substance
abuse/drug abuse does is not limited to moodaltering or psycho-active drugs. Activity is also
considered substance abuse when inappropriately
used (as in the case of propofol and Michael
Jackson's death, or steroids for performance
enhancement in sports). Therefore, mood-altering
and psychoactive substances are not the only drugs
of abuse. Substance abuse often includes problems
with impulse control and impulsivity.
Substance Abuse
 The term "drug abuse" does not exclude dependency,
but is otherwise used in a similar manner in
nonmedical contexts. The terms have a huge range of
definitions related to taking a psychoactive drug or
performance enhancing drug for a non-therapeutic
or non-medical effect. All of these definitions imply a
negative judgment of the drug use in question
(compare with the term responsible drug use for
alternative views).
Substance Abuse
 Some of the drugs most often associated with this term
include alcohol, amphetamines, barbiturates,
benzodiazepines (particularly temazepam, nimetazepam,
and flunitrazepam), cocaine, methaqualone, and opioids.
Use of these drugs may lead to criminal penalty in
addition to possible physical, social, and psychological
harm, both strongly depending on local jurisdiction.
Other definitions of drug abuse fall into four main
categories: public health definitions, mass
communication and vernacular usage, medical
definitions, and political and criminal justice definitions.
Substance Abuse
 Substance abuse is a form of substance-related
disorder.
 Alcohol – withdrawal can kill
 Public health issues