Chemical produced, temperature change, light is produced. Compounds that

Chemical reactions involve the rearranging of the
constituent atoms to create different substances. There are 6 clues to tell if
a chemical reaction has formed. Normally chemical reactions will display
several of these qualities:  an insoluble
precipitate is formed, bubbles are formed, color change is observed, new odor
is produced, temperature change, light is produced. Compounds that react with
each other are called reactants, compounds produced are called products and
products that are solids are called precipitates. Subscripts are used to balance
a compound in a reaction, while coefficients are used to balance the entire
equation in order to satisfy the Law of Conservation of Mass.


The process of digestion is the act of converting food into
chemical substances that the body can absorb into the blood stream to be
utilized by body tissue. This happens when proteins, lipids, carbohydrates are
broken down into simpler compounds for the human body to process (“Digestive
System,” n.d.). Food begins the digestive journey as soon as it is
ingested.  It is masticated (chewed up)
in the mouth then swallowed and pushed down the esophagus with the help of
peristaltic contractions. The stomach breaks up the bolus chemically and
mechanically. The nutrients in chyme is then absorbed in the small intestine,
after which it travels through the large intestine and to the anus to be
excreted. (“Enzymatic digestion,” n.d.)

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Digestion starts in the mouth where food is masticated
(chewed) into smaller pieces. Saliva is rich in amylase, a salivary enzyme that
break down carbohydrates turning them into maltose, maltotriose and dextrins.
(“How Is Starch Changed by the Saliva in the Mouth?” n.d.). The enzyme coats
each starch molecule, and deconstructs it through hydrolysis to turn them into
smaller, more manageable pieces. This separation of long chained starches into
sugars makes it easier to break down later in the body.


The esophagus is a muscular tube, roughly 8 inches in
length, that is lined with a layer of pink tissue called mucosa. It connects
the pharynx to the stomach and transports the bolus of food away from the
mouth.  Automated muscle contractions,
peristalsis, pushes food along the tube. There are sphincters located at both
ends of the esophagus, which open and close after swallowing, when food is
about to enter the stomach or when gas needs to be expelled. (“Normal
Function,” n.d.).


The stomach is where the majority of digestion takes place.
Chemical and mechanical forces break down the bolus and prepare it for further
digestion in the small intestine. Gastric juice, comprised of hydrochloric
acid, water, electrolytes, mucus and an intrinsic factor, is responsible for
the digestion of proteins and fats. The enzymes pepsin and protease, secreted
by stomach lining, breaks down proteins, converting them to peptides which are
further digested by gastric lipase. These stomach enzymes uncoil proteins
strands as part of digestion. Trypsin breaks down protein strands into one two
or three amino acids. (“What Digests First, Protein, Carbohydrates or Fat?”
n.d.). Hydrochloric acid secreted by parietal cells converts pepsinogen into
pepsin and breaks down various nutrients in food. It also kills more bacteria
in food with its high acidity.


Unlike intramolecular forces which hold a single molecule
together, intermolecular forces are responsible for the attraction between
compounds. There are 3 types of intermolecular forces; London dispersion
forces, dipole-dipole forces and hydrogen bonding (Meyers, n.d.). London
dispersion forces- a temporary force of attraction that occurs due to constant
shifting of electrons in opposite molecules. 
This force is the weakest out of the three and occurs between all
molecules, regardless of whether they are polar or not. Dipole-dipole forces- a
permanent force of attraction between the positive end of one polar molecule
and the negative end of another polar molecule.


Hydrogen bonding- the strongest force of attraction that can
occur between two molecules. Hydrogen bonding occurs between a slightly
positive hydrogen on one molecule and a slightly negative atom on another
molecule. The reason this bonding type is so strong is because the atomic
radius of hydrogen is very small, allowing other atoms to come extremely close,
however this only happens when hydrogen bonds with fluorine, oxygen or
nitrogen. HCl(aq) is a polar molecular. Holding the molecule
together is London dispersion forces and dipole-dipole forces as the positive
ends of each molecule attracts the negative ends. This force is permanent and
stronger than London dispersion forces which are only temporary attractions due
to shifting (B, n.d.)


Hydrochloric acid is extremely acidic with a pH of about 2.
Our stomach lining is protected by a thick layer of mucus, however gastric acid
can burn through flesh and metals. Sodium bicarbonate (NaHCO3), secreted by the
pancreas, is a weak base with a pH of about 8.4. It neutralizes gastric acid
and is found in common foods.

An example of a neutralization reaction that will occur in
the stomach as a result of gastric acid coming into contact with the bodies
natural antacid is:

HCL(aq) + NaHCO3(aq) ? NaCl(aq) + H2O(l) + CO2(g)

Hydrochloric acid plus sodium bicarbonate yields sodium
chloride, water and carbon dioxide. This double displacement and neutralization
reaction does occur as a gas and water are produced (gas, water or precipitate
must be a product of double displacement reaction for it to occur).  


There are 5 types of chemical reactions: synthesis,
decomposition, single displacement, double displacement and combustion. Double
displacement reactions are a chemical reaction in which the positive ions of
two ionic compounds switch places to form two new ionic compounds. They must
always produce either a solid, water or gas for a reaction to occur. Neutralization
reactions are a type of double displacement reaction in which an acid reacts
with a base to produce an ionic compound (salt) and water. Acid base reactions
in the stomach are examples of neutralization reactions such as when
hydrochloric acid reacts with sodium bicarbonate.


Alongside the main GI tract, are other organs that help to
digest food and filter out nutrients from waste.

The liver filters toxins out of the blood and produces bile
which is used to further digestion. The gallbladder stores bile from the liver
and holds it until it is needed. The pancreas secrets enzymes used in the small
intestine necessary for digestion. It also makes hormones that regulate the
glucose levels in the blood (“Anatomy of the Liver, Gallbladder &
Pancreas,” n.d.).


The liver is a roughly triangular organ, capable of
regenerating itself.  It is divided up
into 4 distinct lobes; the left, right, caudate, and quadrate lobes. The liver
plays an important role in digestion with the production of bile. Bile is a
mixture of water, bile salts, cholesterol and bilirubin. It is able to emulsify
large quantities of fat and break them up into smaller pieces, that are easier
to digest (“Liver – Anatomy and Function of the Human Liver,” n.d.). Detoxification
of blood also occurs in the liver when blood passes through the hepatic portal.
Hepatocytes continuously monitor and eliminate toxins such as alcohol and


The gallbladder is a small, green sac located under the
liver that stores bile. The absorbent lining of the gallbladder makes it ideal
for collecting excess amounts of bile until it is needed for digestion. When
food enters the small intestine a hormone called cholecystokinin triggers the
bile ducts leading out the gallbladder to open and deliver bile. The secreted
bile helps to break up fats and drain waste products from the liver and excrete
them (“Gallbladder Function, Location & Anatomy,” 2014).


The pancreas is an organ located in the abdomen that is
responsible for converting digested food into fuel for cells. It has two main
functions, aid digestion (exocrine) and regulate blood sugar (endocrine). Exocrine
function: the pancreas produces vital enzymes to aid digestion such as trypsin
and chymotrypsin to breakdown proteins, amylase for carbohydrates and lipase to
break down fats. These juices enter the first part of the small intestine
(duodenum). In addition, bile from the liver to help digest fats, proteins and
starches (“The Pancreas Center,” n.d.).


Most of the process of digestion in the gastroenterological
tract occurs in the small intestine. It is roughly 7.0 m long and is divided
into three sections: the duodenum, jejunum, and ileum. The small intestine breaks
down and absorbs various nutrients from chyme and transports it throughout the
body.  Villi (finger like extensions on
the small intestine wall) absorb passing nutrients and send it off to the blood
stream and other tissues (“Digestive System,” 2014). Most digestive enzymes
enter the small intestine through the pancreatic duct. Proteolytic enzymes,
including trypsin and chymotrypsin rip apart proteins into smaller peptides.


Duodenum – This is the first part of the small intestine as
well as the shortest. It deals with partially digested chyme from the stomach
and plays a vital role in digestion. Chemical secretions from the liver,
pancreas and gallbladder bring in enzymes to facilitate chemical digestion. The
muscular walls of the duodenum are lined with mucosa and epithelial tissue and
microvilli to increase surface area for absorption.  Bile produced in the liver and stored in the
gallbladder emulsifies lipids, breaking them into globular pieces to increase
surface area (“Duodenum – Small Intestine,” n.d.). 


There are three main enzymes secreted by the pancreas that
work in the duodenum, one being trypsin. As a proteolytic enzyme (protein
digesting enzyme), trypsin’s main function is to break the bonds of specific
amino acids to produce peptides (“Trypsin,” n.d.). It also makes the absorption
of vitaminB12 an easier task. The combination of the slightly alkaline
environment of pH 8 optimizes efficiency of the enzyme. Trypsin catalyzes the
hydrolysis of peptide bonds, breaking down proteins into smaller pieces
(“Trypsin,” 2018). 


Dipeptide + H2O -> 2 Amino Acids

Hydrolysis: a double displacement reaction involving water
in which the H2O molecule cleaves in half another molecule. Consequently, one
half of the molecule gets a H+ ion while the other half has the OH- ion. In
biochemistry hydrolysis is used to break down polymers into monomers. Food
ingested takes the form of a polymer which is digested by enzymes who’s
reactions are sped up using hydrolysis. Monomers produced are small enough for
the body absorb (“Structural Biochemistry/Enzyme Catalytic
Mechanism/Hydrolysis,” n.d.).


A periodic trend that describes the tendency of an atom to attract
a bonding pair of atoms. Each atom on the periodic table has an
electronegativity value (EN). The difference in EN in a bond can be used to
predict the type of bond it will form. Covalent bonds share electrons, so the
EN difference would be smaller, whereas ionic bonds that transfer electrons
should have a high EN difference.


There are 3 criteria that must be meet in order for a
chemical reaction to occur.  Reactants
must: collide, collide with proper orientation, collide with enough energy.  Things that can speed up a reaction include: a
catalyst, increase in temperature, stirring, increasing surface area and more.


H2O is a covalent compound as it has an EN of 1.5 making it
a polar covalent molecule. Water has all three types of intermolecular forces,
London dispersion, dipole-dipole and hydrogen bonding, with the strongest and most
prevalent being the latter. Water has a pH of 7 making it safe to consume due
to its unreactive nature. With the proper orientation and speed, the collision
theory allows for two oxygen molecules to bond when the negative dipole meets
the positive side.


 Jejunum – The middle
segment of the small intestine.  With
epithelial cells and layers of villi along folded inner walls, the jejunum is
responsible for the majority of nutrient absorption in the digestive
system.  After passing through this section
of the small intestine, more than 90% of all nutritional content has been
absorbed into the body.

Ileum-  At 3.5m long,
the Ileum is the longest and final segment in the small intestine. Its primary
function is to absorb vitaminB12 and reabsorb conjugated bile salts. The inner
wall is smoother than previous sections and has slower peristaltic
contractions, in addition to being less permeable. To prepare food for excretion,
there are patches of lymphatic tissue designed to detect and extract vitaminB12
(“Ileum,” 2015). 


The large intestine is a 1.8m long tube that prepares food
for excretion. It is broken up into four parts: the ascending colon, the
transverse colon, the descending colon and the sigmoid colon. First, water and
salts are removed from the waste as it passes through the colon during a period
of 36 hours. The waste makes its way to the sigmoid where it is stored until
defecation (“Large Intestine – Anatomy and Physiology,” n.d.). Like the small
intestine, the colon is made up of four layers of tissue, each coated with
villi, mucosa or epithelial cells to remove any final nutrients. A variety of
bacteria is mixed with with the chyme to begin turning it into feces. Bacterial
fermentation releases vitamins K, B1, B2, B6, B12, and biotin, as well as
creates flatulence (gas) from the methane and carbon dioxide in the bowel
(Bradford, 2016).


The rectum is the last part of the digestive system right
before the anus and is about 10cm-15cm long. It’s function is to temporarily
store feces. The muscular pouch holding excrement is able to expand to
accommodate more waste. When waste is about to be expelled, the internal
sphincter relaxes and involuntary and voluntary muscle contractions begin
working (“Rectum Anatomy, Diagram & Function,” 2015).


Ultrasound Technician – An ultrasound technician operates
equipment that uses high frequency sound waves to create images of a patients
internal organs. The work done helps doctors make decisions on patient
treatment, based on any abnormalities present in the imagery. Theses
technicians work directly with patients and doctors and can specialize in
fields such as obstetric and gynecologic, abdominal, breast, vascular, or
cardiac sonography (McKay, n.d.).


Gastroenterologist – A physician with dedicated training and
experience who has studied in the management of diseases of the
gastrointestinal tract and liver. These doctors can treat a variety of
conditions from Hepatitis C to irritable bowel syndrome (IBS). There are
various fields of study, as some physicians may choose to specialize in
hepatology, transplantation or other (“What Is a Gastroenterologist,” n.d.). They
may perform endoscopic procedures in which special instruments are used to view
ones GI tract. Gastroenterologists do not perform surgery however, they can
work alongside a GI surgeon or provide treatment and advice to patients.