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Digestion System Project
Transcript of Digestion System Project
by. Ben Lim and Jenny Lee
in the mouth
by chewing making
easier for us to
Main function of the tongue is to
push food toward the teeth,
helping the process of chewing
is to taste the
food that comes
in through the
The main function of teeth is to break down large food parts into smaller food pieces.
1. Manufactures saliva which helps bolus to go down the esophagus easily.
2. Secretes amylase which helps to break down starch into maltose. (Chemical digestion.)
The main function of the pharynx is it is a passageway for both food and air.
Relating to digestive system, the pharynx receives bolus and pushes down to esophagus.
Function of the epiglottis is to prevent food and drink from going down the wrong passage and prevent shocking. (When happens the body solves by coughing)
The function of
esophagus is to
receive food from
pharynx and send
The function of Cardiac Sphincter is to prevent from bolus to back low into the esophagus.
If bolus does get back to esophagus the symptom is called the heartburn.
The main purpose of the stomach is to break down food and extracts nutrients necessary to the body.
During the extraction of nutrients, stomach uses enzymes created by the stomach and mixes and breaks down food particles.
Pyloric sphincter controls the movement of chyme going into small intestine.
Duodenum's main function is to receive the partly digested foods (chyme) from the stomach and finish the digestion process.
1. Regulates glucose level
2. Produce Urea
3. Produce blood proteins, clotting agents
4. Destroy old RRC
5. Detoxifiy blood
6. Produce bile
7. Stores iron and vistamins
Stores bile produced by liver and release toward duodenum when triggered.
The main function of
pancreas is to produce insulin and enzymes to help break down food.
As digest food reaches the small intestine, this is when 90% of digestion occurs. Most of the nutrients gets absorbed in the small intestine and sends them into the bloodstream
Absorbs most of water and vitamins get absorbed at large intestine. Also transports waste toward rectum and anus.
Most scientists have said that appendix is useless organs, but recently it was discovered as safe house for good bacteria.
Main function of rectum is to store faecal clumps for certain time until they are removed from our body.
The anus is the opening of the digestive tract to eliminate the leftover waste solids.
Other key information relating to Digestive System.
Swallowing and Peristalsis.
Swallowing is the most complex functions of the body.
It requires mouth for closure, tongue for movement of the food, trachea for closing windpipe, guidance toward the esophagus, lastly, muscle contraction called peristalsis.
Function of Insulin in maintaining blood sugar levels.
Insulin (Hormone), is produced and secreted by the pancreas.
To use glucose and the liver's activity Insulin increases cell's activity
Role of Bile
Breaking down Food into Smaller Molecules
The role of bile is to digest and absorb fats and soluble vitamin.
Bile emulsifies fats into small droplets so the body can absorb them as nutrients.
breaks down food into molecules that the body can use
increases reaction rate
can denature at very high temperatures or low temperatures = lose its function
enzymes work on certain subtrates only (e.g. lactase only work on lactose)
Physical Digestion, Absorption
Chemical Digestion, Absorption
The chemical digestion involves sodium bicarbonate from liver due to the HCl and make the chyme alkaline.
pepsinogen (inactive) + HCl → pepsin (active)
Sodium bicarbonate is produced from pancreas -> Pancreatic duct.
Gastric glands release
, which includes pepsinogen, HCl, and water
and breaks them into
The small intestine also releases hormone known as Cholecytokinin. As known as CCK.
CCK makes the enzyme to release and response to the nutrients in small intestines.
Mostly digested chyme will pass through the small intestine and get digested due to the movement through the SI. While going through the SI nutrients get absorbed into our blood stream.
Structure of villus
The structure is adapted to the shape so the villi can absorb nutrients efficiently.
The structure of micro villi
Microvilli are tiny extensions of the plasma membrane and they are filled with cytoplasm and have a core of actin filaments.
Function of Capillaries
Acts as an passage way for oxygen and nutrients. Transports them to tissues of the body.
Smallest blood vessel
Function of lacteal
Lacteal collects excess fluids and remove them
The function of Anaerobic Bacteria in Colon.
The bacteria limits the ability of pathogenic bacteria in the colon from proliferating
Correct use of dissection microscope.
Enzymes in the
fatty acids and glycerols
short polypeptide chains
Step1: Set microscope on a stable surface such as a table or laboratory bench. Assure there is adequate light on or below the stage to illuminate your specimen.
Step2: Clean lenses with lens paper and lens cleaning solution, if necessary.
Step3: Place specimen to be viewed, or an exemplar, on the stage
Step4: Adjust the inter-pupillary distance by moving the eyepieces in or out until only one image is seen with both eyes open.
Step5:Adjust the course adjustment knob until the object is roughly in focus in the ocular that does not have an adjustment.
Step6: Adjust the second ocular by rotating the adjustment ring (diopter adjustment) until the specimen is in focus. Check that the specimen is in focus when both eyes are used.
produced in the
Step7: Repeat adjustments described in Steps 4, 5, 6, and 7 until both oculars are focused at the same point. (These steps are not required with a monocular scope.)
Step8: Place specimen to be observed on the stage of the microscope.
Step 9:Adjust the course and fine adjustments (some scopes have only one focus adjustment knob) until the specimen, or the part of the specimen to be observed, is in focus.
Step 10:Rotate the nose piece, the zoom ring, or the zoom knob to change objective lenses for the increase or decrease of magnification. Change objective lens magnification to the desired level for the feature being observed.
(and other disacharaaridases):
breaks down maltose into glucose
breaks down peptides into amino acids
breaks down nucleotides into base + phosphate + sugar
Roles of Substances
Water moistens the food and makes it softer and easier to digest. If there were no water in digestive juices, this will lead to indigestion, constipation, and few other problems
Sodium Bicarbonate NaHCO3
When the pancreas releases sodium bicarbonate into the duodenum, this substance increases the pH of the chyme (food from the stomach, which as a pH of 2.5), and adjusts it to a more basic environment (pH = 8.5)
Hydrochloric acid (HCl) in gastric juice
The HCl reacts with pepsinogen in the gastric juice to make it active into pepsin, which is an enzyme that breaks down protein.
Mucus in Gastric Juice
The mucus in gastric juice protects the stomach that can be damaged by the low pH (acidity).
Why Different pH levels in different regions?
Mouth: pH 7 - we don't want to taste sour or bitter
Stomach: pH 2.5 - HCl needs to turn pepsinogen into pepsin (enzyme), and the acidity kills bacteria
Duodenum: pH 8.5 - many enzymic reaction occurs here. Enzymes must be in optimum pH levels so that they can function properly and break down food