• Prepared By:
• Md. Mohabbulla Mohib
• Istiaque Hasan
• Faisal Bin Kamal
• AKM Faisal
• consists of structures that aid in the ingestion and digestion of
• includes the mouth, esophagus, stomach, duodenum
Ingestion is the process of consuming something and taking it into the
Digestion is the mechanical and chemical breaking down of food into
smaller components, to a form that can be absorbed
• consists of the small and large intestines
Major Structures in the Mouth
• teeth – to grind the food
• salivary glands – moisten food and mucous membranes and begin
• tongue – to push the food to the pharynx to initiate swallowing
the lower esophageal sphincter (LES) prevents reflux of food in
the stomach back into the lower esophagus
made up of 5 layers of smooth muscle
The mucus lining of the stomach protects the stomach walls from
the action of stomach acid
The walls of the stomach are lined with parietal cells that secrete
mucus, pepsinogen and hydrochloric acid.
2 types of contractions:
1.) tonus contractions – continuous contractions
2.) rhythmic contractions – may be slow or fast –
responsible for the mixing of food and peristaltic movement
• When excess acid is produced a condition
known as acid indigestion results.
• If excess acid is forced into the esophagus
acid reflux or “heart burn” results.
• These conditions are sometimes called
gastro-esophageal reflux disease
• Excess stomach acid results in a state of
discomfort known as acid indigestion
• Acid indigestion may result form a variety of
• Alcohol consumption
• Eating certain foods
• Certain Drugs, i.e. Aspirin
• If the Lower Esophageal Sphincter (LES) is not working
properly creating a dysfunction – the acid from the
stomach can backflow into the esophagus.
• What is Antacids?
• Antacids are a form of medicine used (normally in a
tablet or liquid form) to help restore the pH balance in
your stomach. It is an OTC drug.
• It is mainly weak bases that are used to neutralize
excess stomach acid
• Most antacids are weak inorganic bases
• Common examples include
• Alginate Antacids
should not absorbable or cause systemic alkalosis.
should not liberate carbon dioxide &cause rebound
should not interfere with absorption of food.
should not be a laxative or cause constipation.
should be quick acting & exert its effect over a longer
period of time.
should buffer in the pH range 4-6.
should probably inhibit pepsin.
should be inexpensive.
• Antacids directly neutralize acidity, increasing the pH
• In addition to neutralizing excess stomach acid they
may be helpful in relieving pain and discomfort, and
allowing the mucus layer in the stomach lining to
• They are often used to treat ulcers by preventing the
stomach acids from attacking the stomach lining
allowing it to heal.
• Although their principle mechanism of action is
reduction of intra gastric acidity, they can also
promote mucosal defense mechanism by mucosal
• Reduction of pain associated with acid-related disorders
• Raising gastric pH from 1.3 to 1.6 neutralizes 50% of the
• Raising gastric pH 1 point (1.3 to 2.3) neutralizes 90% of
the gastric acid.
• Calcium Carbonate is a strong and fast-acting antacid.
• Antacids that contain calcium carbonate may work longer
than those containing sodium bicarbonate or magnesium.
CaCO3 + 2 HCl CaCl2 + H2O + CO2
ALUMINUM AND MAGNESIUM
• Aluminum salts dissolve slowly in the stomach, gradually
relieving heartburn symptoms. But they may cause
constipation. Magnesium salts on the other hand, act
quickly to neutralize acid but are known to cause
• Because the effects of aluminum and magnesium can
balance each other out, using them together is often
considered an effective treatment for digestive upset.
Al(OH)3 + 3 HCl AlCl3 + 3 H2O
Mg(OH)2 + 2 HCl MgCl2 + 2 H2O
• Sodium bicarbonate can work quickly to relieve heartburn
symptoms. But it's also quickly eliminated from the
stomach so relief may not last long.
NaHCO3 + HCl NaCl + H2O + CO2
• Alginate Antacids
• Alginate antacids don't work the way other antacids do.
These antacids contain both calcium carbonate and
alginic acid. The alginic acid helps form a barrier that
floats on top of the acid in your stomach. This barrier
helps prevent stomach acid from moving up into
• The calcium carbonate works to neutralize the stomach
acid that pushes through the barrier and into your
•Loss of appetite
• produce a
of carbon dioxide
gas, people often
• can cause
• Produces gas
• may results in
• Loss of
Patient with kidney failure or heart disease: Sodium bicarbonate has
high sodium content and is not appropriate for people who are on salt
restricted diets or have congestive heart failure, high blood pressure, or
In pregnancy: If you are pregnant, antacids are safe to use for
heartburn symptoms. But do not use antacids that have sodium
bicarbonate. They can cause fluid buildup. During pregnancy it is okay
to use antacids that have calcium carbonate (such as Tums).
Problem with liver and kidney : If you have a problem with the
function of your kidneys or liver, you should be careful with using
antacids. All drugs are broken down and removed from the body by the
combined action of the liver and kidneys. If your kidneys are not
working correctly, it is possible that too much of the drug will build up in
• When antacids are taken with acidic drugs such as
digoxin , phenytoin , chlorpromazine , isoniazid, they
cause the absorption of the acidic drugs to be decreased,
which causes low blood concentrations of the drugs,
which ultimately results in reduced effects of the drugs.
• Antacids that contain magnesium hydroxide when taken
with some other medications (such as tetracycline) will
bind to the drug, and reduce its absorption and effects
Constipation can occur in patients using calcium
carbonate and aluminum containing antacids.
Diarrhea is a common adverse effect of magnesium- and
sodium-containing antacids. If diarrhea occurs, the
patient may alternate the antacid mixture with aluminum