Digestion Physiology
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Transcript of Digestion Physiology
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8/8/2019 Digestion Physiology
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Digestion, involving physical and chemicalbreakdown of food particles, happensthrough the alimentary canal and utilizes
various enzymes from various accessoryorgans to digestion. Such enzymes exhibitsspecificity and works under particulartemperature and pH values; these variables
are critical to maintaining the enzymesstructure which affects the digestion ofspecific food particle.
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High temperature may destabilize the
tertiary to quaternary structure of the
enzyme, or simply called itsdenaturation.
Low temperature, on the other hand,may inhibit catalytic activity for it
reduces the total kinetic energy of the
enzymes.
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The pH levels are critical also for the
enzymes require or work most efficiently
under the certain pH level wherein theycan maintain their tertiary to quaternary
structures.
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Protein receives primary digestion in the
stomach with the gastric juice working
on them pepsin is the more specificenzyme digesting the protein. Protein is
finally broken down into its simplest form
in the small intestine with a long list of
enzymes.
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Lipids or fats are the hardest to digest
because of their nature hydrophobic.
Fat digestion first occurs in the stomachwith lipase. However, same with the
other biomolecules, fats are digested in
the small intestine further into its smallest
simplest form with bile salts released byliver by the action of CCK hormone.
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The materials used in this part of the
exercise were egg white and pepsin.
Egg white was used because itcharacteristically composed of proteinmolecules Albumin making it a good
source of protein in ones diet. Pepsin
was used for it is the enzyme acting onprotein and is produced by chief cells ofstomach and HCl for activation.
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Five test tubes were obtained from thestockroom and labeled P1 to P5. Oneach was placed a small piece of hard-boiled egg white. The followingsubstances were added:
P1: pepsin + water
P2: pepsin +HCl
P3: pepsin + HCl in ice bath
P4: water +HClP5: pepsin + NaOH
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Each test tube, except P3, was
subjected to water bath incubation
under37C for 90 minutes and resultswere recorded as to whether changes in
color occurred or not and whether the
egg white slice was digested or not.
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The materials used in this part of theexercise were cream, bile salts, water,and pancreatin.
Cream was used in experiment for it iscomposed of non-water-soluble lipids or
fats.
Bile salts were used for this is the enzyme
acting on lipids. It is produced in liverand concentrated in gall bladder beforereleasing to the small intestine. Releaseof bile salts is triggered by CCK hormone
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Incubation in water bath was utilized to
inspect digestion as it happens on
certain temperature requirement.Variations in temperature may affect the
total digestive process.
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Three test tubes were obtained from thestockroom and labeled F1 to F3. 3.0 ml creamwas placed in each tube. The followingdesignated substances were added:
F1: 5.0 ml distilled water + bile saltsF2: pancreatin solution
F3: pancreatin + bile salts
Each tube was shook vigorously to mix thecontents. Afterwards, pH of each substance ineach test tube were recorded and served as
initial pH. The tubes were then subjected towater bath incubation under37C for onehour. Recording of pH measurements wasdone at 20-minute intervals. Results weretabulated
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Set-up TheoreticalResults
P1-
P2 ++++
P3 -
P4 +
P5 _
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Theoretically, P1, P3, and P5 will not be
observed to digest the slices of egg
white. In P4, digestion would be
observed, while in P2, digestion would bevery obvious. P2 and P3 contained the
same chemicals, but P3 was put in an
ice bath that inhibited digestion as
opposed to the thorough digestion thathappened in P2.
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Set-up and a
few grains of
bile salts
Initial After 20
minutes of
incubation
After 40
minutes of
incubation
After 60
minutes of
incubation
F1(Distilled water and a few grainsof bile salts)
7.88
7.86
7.8
2 7.86
F2(pancreatin solution)
7.29 6.90 6.77 6.79
F3(pancreatin solution and a few
grains of bile salts)
7.29 7.05 6.63 7.16
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There is a general trend of decreasing
pH through time. Theoretically, the pH
levels in the three test tubes would alldecrease unlike the recorded values in
F1. Moreover, F3 should exhibit the
greatest decrease in pH level and not by
F2. Following F3 would be F2 and then F1which should only exhibit a slight
decrease in pH level.
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Proteins only start to be digested once it
enters the stomach where the gastric
juices are produced resulting in a low pHlevel. Pepsin, along with HCl in the
stomach, are the primary substances
that breaks down Proteins. Further
digestion takes place as the proteins aretransported into the small intestines
wherein various enzymes act upon it.
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In this experiment, the digestive
capacity HCl and Pepsin towards
Protein, represented by the egg white,was tested. Active digestion of the egg
white would be manifested by its color
changes and decrease in overall size
after the activity.
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Digestion of Triglycerides or Fats is usually thelast process to take place. This is due to thehydrophobic property of fats that gives themthe tendency to aggregate in large droplets.The water-soluble property of the digestive
enzymes all the more makes the entire processharder because it lessens the contact betweenfat and water. Thus, the fat molecules shouldbe broken down into monomers or simplerforms in order for its nutrients to be absorbed,
for instance, by the bloodstream. There are alot of substances involved in these processesand their functions are affected by certainfactors such as temperature and pH.
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After the initial pH measurements, thetubes were incubated in a 37C water bathand their pH levels were measured inintervals of 20 minutes. Comparing thevalues gathered after the first interval tothose gathered initially, there is anobservable decrease in the pH levels. Thisdecreasing trend would continue tomanifest as the time of incubation prolongs.This pH level lowering shows the progressivedigestion of triglycerides. It demonstratesthat the more the substances pancreatinand bile salts act on the triglyceride, themore it lowers the pH level of the solution.Also, the combination of the salts and thepancreatin demonstrated the mosteffective breakdown of the triglycerides
thus exhibiting the lowest initial pH and thehighest drop of the succeeding pH levels.