Sbp 3114-Salivary Secretion
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Transcript of Sbp 3114-Salivary Secretion
SBP 3114 – RESPIRATORY, DIGESTIVE AND ENVIRONMENTAL SYSTEM
SALIVARY SECRETION
Introduction
Saliva is produced in and secreted from salivary glands. It contains many
important substances, including electrolytes, mucus, antibacterial compounds
and various enzymes. Saliva lubricates the mouth and starts the breakdown of
chewed food. The basic secretory units of salivary glands are clusters of cells
called ‘acini’. These cells secrete a fluid that contains water, electrolytes, mucus
and enzymes, all of which flow out of the acinus into collecting duct. Most
animals including human, have three major pairs of salivary glands that secrete
saliva:
Parotid glands
Submaxillary glands
Sublingual glands
Secretion of saliva is stimulated both by the sympathetic nervous system and
the para- sympathetic, which control both the volume and type of saliva
secreted. The saliva stimulated by sympathetic innervations is thicker, and
saliva stimulated parasympathetically is more watery. Potent stimuli for
increased salivation include the presence of food or irritating substances in the
mouth and thoughts of or the smell of food.
Diseases of the salivary glands and ducts are not uncommon in animal and man,
and excessive salivation is a symptom of almost and lesion in the oral cavity.
Methods and Materials
Materials:
Measuring cylinder, test tube and pipette
Rubber band and reading materials
Vinegar solution
Starch solution
Normal saline (0.9% NaCl)
Iodine solution
Tile
Toothpick
Methodology:
There are four different tests will be carried out for this experiment. Each test
needs one volunteer. Therefore four volunteers are needed and they need to
gargle with tap water before doing the experiment.
Test 1. Salivary secretion while resting:
Volunteer needs to stay still while reading (no voice) for 10 minutes.
Don’t swallow and spill out the saliva into measuring cylinder when
necessarily. Record the volume of saliva and keep it for further test (Test
5).
Test 2. Salivary secretion while chewing:
Volunteer needs to stay still while reading and chewing two rubber bands.
Collect the saliva for 10 minutes and keep it for further test (Test 5).
Test 3. Salivary secretion from chemical stimulation:
Volunteer needs to gargle with 0.5 ml of vinegar solution for 10 minutes.
Collect the saliva immediately after the solution was being discarded.
Record the volume of saliva for 3 minutes and keep it for further test (Test
5).
Test 4. Salivary secretion while talking:
Volunteer needs to talk to friend for 10 minutes. Collect and measure the
volume of saliva and keep it for further test (Test 5).
Test 5. Activity of Amylase Enzyme
Add 5 ml of starch solution into a test tube. Next, add 3 drops of saliva
and 9 drops of NaCl solution into the previous test tube. Mix them up and
then put one drop of mixture followed by iodine solution on tile every 30
seconds. Stir it with the toothpick. The presence of amylase enzyme in
saliva will convert starch to maltase while maltase will lead to changes of
iodine colour (yellow) to blue-black.
Record the time when the blue-black colour is not visible after the iodine is
added. Cancel the test if you still can see the colour after 15 minutes. Do
not use the same mixtures that have been added iodine.
Carry out this amylase enzyme activity test with the saliva that you have
collected before. Each group should have its own test tube.
Questions
A. Compare the volume of saliva that secreted on Test 1 - 4, and explain
the results that obtained.
B. Compare the activity of amylase enzyme in saliva on Test 1 - 4, and
explain the results that obtained.
30 seconds 30 seconds 30 seconds
1st well 2nd well 3rd well
1 drop of
iodine
1 drop of MIXTURE from the test tube
1 drop of iodine
1 drop of MIXTURE from the test tube
1 drop of iodine
Until 15 minutes or fully turned yellow
1 drop of MIXTURE from the test tube
MIXTURETest tube containing mixture of 5 ml starch, 3 drops saliva and 9 drops NaCl solution.
Stir with toothpick
Stir with toothpick
Stir with toothpick