1. bile salts in food digestion is

1.     ) Chemical digestion begins with the
secretion of salivary amylase and the first enzyme to access the food that was
ingested is called the amylase which breaks starch into maltose after the
enzyme has been activated by the Cl- in saliva. The enzyme amylase is located
in the salivary glands which produces salivary amylase which once again helps
to break starch when we chew our food. (Silverthorn et al.,)


b) When the food reaches the stomach, the stomach forms stomach acid and
HCL which ultimately activates the pepsin. Pepsin is an enzyme and its job is
to break down proteins that are in your food into smaller pieces like for
example amino acids. Parietal cells deep in the gastric glands secrete gastric
acid which helps to kill all the bacteria and other ingested microorganisms, and
it inactivates salivary amylase, which stops carbohydrate digestion that begins
in the mouth. (Silverthorn et al.,)

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c) The accessory organs are pancreas and liver. The pancreas’s role is
to produce digestive enzymes like pancreatic proteases such as, trypsin and
pepsin which aids us to digest proteins. On the other hand, liver secretes bile
which is a digestive enzyme that has salts that help break down fats. Bile is
released by liver through small intestine.

(Silverthorn et al.,)



d) the purpose of bile salts in food digestion is to facilitate
enzymatic fat digestion so, they act as detergents to solubilize fats during
the process of digestion. Bile salts are produced in the liver then is sent out
to the small intestine. Bile salts are sent to the gallbladder to for storage
and concentration. Secretin is released by the presence of acidic chime in the
duodenum. This hormone helps stimulate bicarbonate secretion which expands the
amount of bile. (Silverthorn et al.,)



a)    the muscles that are located within
the wall of the small intestine are the circular and longitudinal muscles. When
these muscles are grouped together in a layer called the muscularis externa. This
specific region is responsible for peristalsis which is the muscle contractions
that transfers food from one section of the GI tract to the next. (Silverthorn
et al.,)




b)    The three main types of motility
that occur within the gastrointestinal tract are segmental contractions,
peristaltic contractions and migrating motor complex(MMC). Segmental
contraction takes place in the large intestine and small intestine and it is
responsible for mixing the intestinal contents, and making sure they stay in
contact with the absorptive epithelium. Secondly, peristaltsis type is
basically waves of contraction that move from one section of the GI tract to
the next. The last type of motility is the migrating motor complex(MMC) which is
a variety of contractions that starts off in the empty stomach and making its
way to the large intestine.  Its known as
a housekeeping function becacause it is responsible for sweeping remaining food
and bacteria out of the GI tract and placed into the large intestine. (Silverthorn
et al.,)


c)     The absorption of glucose by
intestinal cells uses transporters such as, the apical Na+ glucose SGLT
symporter and the basolateral GLUT2 transporter. These transporters help to
move glucose. On the other hand ,Fructose absorption doesnt depend on Na+ and
it moves across the apical membrane by a facilitated diffusion meaning it need
help from a protein to pass through called the GLUT5 transporter and across the
basolateral membrane by GLUT2. (Silverthorn et al.,)



a)  cells
that absorb the majority of the nutrients that exist in food includes enterocytes.

Their key role is to absorb ions and nutrients into the  extracellular fluid(ECF). The majority of nutrients
absorption happens in the small intestine. (Silverthorn et al.,)


b) the effect that surface area has on the absorption
of nutrients is it increases the surface area of the small intestine making
room for more nutrients to be absorbed. For example, a finger-like extentions (microvilli)
of the cell membrane that increase the surface area for absorption of
materials. (Silverthorn et al.,)

c) the forms that lipid must be in order to be
absorbed in the GI tract is monoglyceride and fatty acids. The two helpers that
break down the fats into monoglycerides and fatty acids are the pancreatic
lipase and colipase. Since fats are lipophilic, they are absorbed primarily by
simple diffusion meaning that fats do not need help from a protein for example.

(Silverthorn et al.,)